Understanding Fire Scene Electrical Damage

Just about everything has been debunked. So there's nothing reliable at this point in time. But I think there is some current research right now in the works that's being reviewed. So we'll see where that ends up. Terminology wise, a little bit of a pet peeve of mine. Kind of want to go through this first. So the one thing that kind of drives me nuts when we're working out on fire scenes is people say, well, we got to go look for arcs. and unless your fire scene is still energized you're not going to find any arcs on your scene because the arc per 921 is the actual discharge from some sort of electrical fault or maybe it's a an intentional thing or a switch opening or closing so the arc is the actual discharge that will cause our anomalies on our wiring 921 refers to an arc site as the location with the damage caused by an arc a bead is defined as a rounded globule of re-solidified metal. What I don't like about this definition is it says it's on the ends of the remains of a conductor, which, like I said, you can see at the bottom here, insinuates that every arcing event results in the conductor or conductors being severed, which is definitely not the case. I think I put in a proposal for this next edition of 921 coming out this summer. They did tweak that to say metal on the remains instead of at the end of the remains. And then I think they added conductor or conductors. One of the other proposals that I put in was for this definition here. And that was just a generic arc melting definition. So that because the other problem with a bead is it's really just a characteristic of evidence of arcing. And so this arc melting definition kind of encapsulates. everything, all the characteristics of arcing that are presented in 921. And so I believe that was accepted by the committee and will be in the next edition as well. All right. So I'm not going to read through all this. It's just kind of up there for your benefit. One of the first things I like to throw out here though is the very first sentence says abnormal electrical activity will usually produce characteristic damage. And outside of my full presentations that I give, one of the things I really like to stress is that in order to know how something might fail, you have to know how it works under normal circumstances. So in order to know what abnormal electrical activity is, you better know what normal electrical activity is. The big thing about when we talk about damage on electrical systems is there really are no absolutes and there's a lot of times or there are maybe not a lot there are some times where you're not going to be able to make some sort of conclusion and you just have to throw your hands up and say I don't know which is perfectly acceptable. I try and make people in my classes get used to saying I don't know a lot because it really does happen and nobody should be ashamed of that. So 921. The 2017 edition, and as far as I know, the 2020 edition isn't going to change any of these, lists all these characteristics for arc melting. And I'm going to focus on all of them but the last two, because those are ones that are readily available or can be easily seen on a fire scene by you or myself or anybody else, unless their eyesight's really poor. but you can see all these without the aid of some specialized equipment. Maybe you get a little magnifying glass or something like that, but these last two are going to be something that you're probably going to need a metallurgist for. So we're going to go through these one by one and just go through some photos. The first characteristic of the cables, we had a researcher from Japan at the Fire Research Lab years ago when I was an intern there. And he basically copied my research for my master's thesis and did the same thing with Japanese cables. And so we found that, lo and behold, arc melting looks the same in Japan as it does in the United States. So the question or the thing that kind of, I think, will help an investigator most often when they're... looking at this type of damage is asking themselves how is it that a fire could do this limited damage to a cable or conductor like this so you can see in the bottom left We've got very pristine wiring. I'll see if I can, I'm not going to bother, I'll screw it up and see if I could get a pointer. But you'll see there's lines that run the length of the conductor from side to side. We've got a very sharp line of demarcation. Oops, go back. We've got a sharp line of demarcation where, you know, the conductor's pristine condition and then it's melted. And in fact, the two adjacent areas of damage from the arcing are on the most protected areas of the conductors because they're in between the two conductors. So there's nothing but insulation in between there. Fire is not precise enough to create this like one or two millimeters sized jet to punch in between two conductors and cause melting to occur. So that's just one way to go about kind of the mental exercise of. trying to identify this type of damage. Okay, again, this is a, I'm not a huge fan of using a single conductor, but sometimes that might be all you have, because maybe you pull a conductor out of conduit, and the other side of the arc site is the conduit itself, and nobody has the time, nor usually the equipment, to section conduit from end to end to find the arc site on the inside. So, but I know this was an arc. or an arc melting created by arcing because it was a lab generated or a test burn. So I know that for a fact it's what it is, but you can see very pristine conductor up until the area of the damage, and then it's pristine beyond that. You can kind of see some longitudinal lines here, and I'll get to those in a little bit. It's a later characteristic, but it's something to kind of keep in the back of your mind. um, when a liquid or all liquids have some sort of surface tension to them. And because of that, they like to form round shapes and molten copper is no different. So when we melt copper like this, it's going to create these beads. And, uh, which, and so that's a good characteristic to look at. Um, they're very nice and smooth. You can almost see spatter or, um, almost like, uh, all the waves, you know, waves like a liquid wave expanding or radiating out from the arc site. Those are good indicators that this is, was molten for a short period of time. The, again going back to that first slide, this is a non-metallic sheath cable or commonly called Romex is the, a brand name, and this was from a test burn and in this case the hot or the ungrounded conductor is on the top, the ground is in the middle, and the neutral is on the bottom. So going back to the first slide, how is it that fire impingement is going to be so localized and focused that it's going to melt two out of the three conductors and leave the third conductor that's a millimeter away completely undamaged? Again, it's just kind of repeating the same question over and over. There's no way that fire is going to be this precise. Okay, and again, a localized point of contact. So these conductors, it's the same setup. This is another test burn. Hot conductors on the top, ground in the middle, neutral on the bottom. A very, generally a very localized area of damage, usually where the two conductors are closest together. Occasionally we get all three conductors involved. That's not unheard of. Let's see here. Keep on going. Again, the corresponding areas of damage. These were lab tests. So hot conductor on the top, ground in the middle, neutral on the bottom. Again, I only touched two out of the three conductors. One thing you'll notice on both of these, there is a bead or a rounded shape on one and a notch or a little bite taken out of the other conductor. So good terms to use when describing arc melting. and things to look for are mass loss and mass transfer. So you can see on the picture on the left, I've got mass loss on the hot conductor on top, and I've got mass transfer from that hot conductor to the ground in the middle. And I've also got it kind of spread around the perimeter of that or the circumference of that top conductor. And the same thing on the right side. I've got a nice bead on the top conductor and a notch taken out of the ground. And that's just, it's the... The direction that mass travels or material travels is kind of a function of which direction the electrons are flowing at any given time because it's alternating current. We're changing the direction of current flow which means we're changing the direction of our electron flow. So that's where our how our mass moves when something like this happens. Resolidification waves, that's the the phrase I was looking for earlier. So again because these are molten and it cools very quickly we can freeze these waves in the metal. These were lab generated artifacts. On the left we took these pictures under a scanning electron microscope and then we tried to recreate the same image under a regular microscope on the right. So you can see the mass loss on the upper conductor and then it was transferred to the middle ground conductor. So these can be quite obvious at times and sometimes not so much, you know, but if you find them it should be a pretty good indicator that you've got arcing going on. So when I talked about those longitudinal lines earlier, I was referring to these copper drawing lines. And the way copper wiring is made is you take a blank or a block or a cylinder of copper and you draw it through successively smaller dies until it gets to the proper diameter. And because you're pulling it through these dies, you're creating tool marks on the surface of those conductors. And those tool marks, you can see here, these longitudinal lines running the length of the conductor, they're scratches or tool marks, whatever you want to call them. If you still see these on your conductors, they are probably the most, probably one of the best indicators that your conductor wasn't on the verge of melting by fire impingement. Because fire is going to be melting the entire mass of that conductor. And because these are so minute. they should be one of the first characteristics that are obliterated by fire impingement. So given that, if you still have them and like here you can see they're intact up to the area of my cursor, I'll see if I can do this, you can see them up to the area of damage and then they just completely are obliterated because of the arc melting. So that's something to keep in mind. Again, like you see in the bottom bullet point here, if they're not present, that's a very good indicator that the entire conductor is starting to melt, possibly from fire impingement. There we go. All right, so small beads and divots. It's possible that we might not have a super localized area of damage because we either have arcing through char or whatever. delayed activation of a circuit breaker or fuse. I should say that delay is usually a result from either arcing through char or we have maybe some resistance. I'm getting all mixed up myself. We either have lower voltages or we have a we don't have a low resistance fault so maybe I'm conducting through some charred insulation. So it's not a low resistance fault. So because I don't have a low resistance, my current is not as high, which means my circuit breaker or my fuse doesn't react as quickly. Nick Carey over in London or in the UK did his doctoral dissertation on arcing and arc mapping and the damage produced. And he referred to this as arcing through char because, and he kind of, one of the descriptors he used was basically a sandpaper type feel. So it's not a typical notch and bead kind of scenario. It was more very fine damage that the surface of the conductor was slightly melted, but didn't have a ton of mass loss. Okay, so this isn't in 921, but it's still a good indicator in that arcing is an explosion. And so based on the severity of that explosion, we're going to be expelling. material or mass from that fault location. And fire is not going to allow the laws of gravity to take a break. And the molten metal is not going to go upwards if it's melting by fire impingement. So these sparks are ejected when an arc occurs and that blows material in all directions. So if you find a location of melting, and you've got spatter on the enclosure or somewhere up above, probably a good indicator it wasn't melting by fire because these molten particles are not going to... defy the laws of gravity. One thing I'll just, I might be getting ahead of myself, but I, because I'm using the terminology, one thing that, actually, no, I'll come back to it in a few slides. Never mind. Instructor's getting ahead of himself. Sprayed particles. Like I said, mass transfer is a good term. You can see here, I've got, it's a meter socket, and the three jaws on top, which they're kind of cut off a little bit, are intact. The lower left jaw is intact. but then the two on the lower right and in the middle, bottom middle, are both missing a lot of material. So, again, good indicators that I've got some sort of damage there that I need to look at. Okay, so one thing you'll have noticed, or hopefully you'll have noticed as you go through these pictures, is that each picture doesn't necessarily just have one characteristic. A lot of them have more than one characteristic. So the fact that you have more than one should help you in coming to a conclusion as to what am I dealing with here. But there is no requirement that you have to have every single characteristic present in order to identify an artifact. So this is here. I won't go through every one of these because every definition is the same. But what I wanted to show is that. Since 2008 up till now and I believe 2020, the definition of a bead other than the slight change that I proposed as far as on the remains hasn't changed. And you'll see that a bead by definition is created by an arcing event. There was a paper published in 2012 that was submitted to the 921 committee. that basically said that beads caused by fire impingement and arc melting or arcing were visually indistinguishable. And the problem with that paper is obviously they're using the incorrect terminology. A bead by definition in 921 is an electrical caused event or artifact. And I like to use the term globule to refer to you know molten material caused by melting by fire. There were some other issues with that paper. Largely, they were testing methodology issues that weren't consistent with what we'd see in a fire. So what I kind of wanted to throw in here or throw this in here is there's a paper out there. You may see it someday in court or have it thrown around by a defense expert or an opposing party. And that paper was not accepted in the 921. So if you ever see that, you can kind of take a look at and say, well. the testing methodology is not the best and it wasn't adopted into 921. All right, so factors that are going to influence how much damage we have from an arc are going to include the length of the circuit, the size of the wire, the conductors, the voltage that the system's running at, so if it's a regular 120 volt system versus maybe it's a low voltage system of 30 volts, and then the resistance at the faulting location. Those are all going to play into how much current is allowed to flow at the fault, which is going to dictate how long it takes for that circuit breaker or fuse to operate. And the reason why that's important is whether or not we have a long duration versus a short duration arcing event. So long duration, we're going to have more mass loss and short duration, we're going to have less mass loss. You'll see, again, another kind of nitpicky terminology thing. Some in the electrical engineering world, they like to use a long-duration arcing event they refer to as an arc, and a short-duration arcing event they refer to as a spark. I really don't like those definitions because, to me, an arc is an arc, and all I'm doing is putting a, is it long-duration or short-duration? And for the most part, we usually don't really know. because we're looking at it after the fact. We're not there to watch it. So I just like to use it's either long duration or short duration. Furthermore, 921 talks about an arc as being the actual discharge, and a spark is a particle that's glowing, and it's either glowing because it's so hot that it's glowing, meaning it's probably around 1,000 degrees Fahrenheit or higher, or it has combustion. occurring on its surface. So sparks in my world, I like to think of them. I like to keep things simple. A spark is if I arc two wires together, the particles that fly away, the mass loss. are the sparks or I can have sparks from welding or grinding or cutting. Those are all, you know, the ignition handbook refers to those as mechanical sparks because it's a physical particle. So I think I beat that enough. So just kind of an example of a short duration arcing event. This is a lab generated artifact, hot conductor on the top, ground in the middle, neutral on the bottom. So you can see I've got very localized damage. I ended up severing one conductor. And what we did was we measured the voltage and the current. And this was an open circuit, so no current was flowing until we had enough charred insulation that current was able to punch through and create a fault. So you'll see we've got a nice sinusoidal waveform, no current flow. And then at some point, the current shoots up to over 450 amps, trips the circuit breaker, stops the arc, and... a little bit less than half a cycle, no more current flow, no more voltage. So that's a short duration arcing event. Long duration arcing event, like this one, same type of test, but you see now we only have one conductor left, that's the neutral conductor. We've completely zipped away and vaporized two out of the three conductors, there's about four inches of conductor missing there, a little bit less. Again, how is fire going to melt, selectively melt? two out of the three conductors there's really no way and you can see in the the diet or the waveforms we've got voltage and current flow and we've got a long duration arcing event this one I only have a portion of the waveforms and we're only getting about it's at least a quarter of a second of arcing as opposed to that fraction of a cycle before so what causes arc melting or arcing probably could have let off with this, but what happens is our insulation breaks down on our conductors, and this can be a function of either fire impingement or it could have been separate from fire. So this is one of the reasons why I kind of dislike the direction 921's going, and that they're referring to arc mapping as a fire pattern, because in my opinion, by saying arc mapping is a fire pattern, you're automatically assuming that every arc site that you find caused by fire impingement and we don't really know that until we look at them all and figure out what what the context is. But so that's just my opinion. So when we get arcing caused by fire impingement we call it arcing through char. So heat's damaging the insulation. That insulation becomes a temperature dependent semiconductor meaning the higher the temperature goes the better of a conductor it is and if I lower the temperature it actually becomes a worse conductor. and we're going to get to a point where we're able to actually sustain current flow and it just punches through the last atom that's intact and now we have a fault. 921 talks about arc tracking and arcing through char that defines them both. So arc tracking is when we have electricity flowing across the surface of a conductor or an insulator. That's usually because we've got insulator corrosion We've got some contaminants, we've got moisture or all of the above or a mixture of the above. And then arcing through char is we have some sort of external heating that breaks down the insulation. So arc tracking kind of is the electricity is causing the carbonized path, arcing through char is external heat causing the carbonized path. Alright, so that's all the electrical caused stuff. Now let's get into the fire caused stuff. we're going to focus on the first three because those are the ones we can see without any fancy instrumentation or chemicals or supplies. So the first one is the effects of gravity. So arcing is very quick. A circuit breaker, if used as supposed to under normal circumstances, stop that arc very quickly. Therefore the molten metal is going to cool down quickly and it's going to be kind of frozen in time and gravity is not really going to usually have time to work on it. as opposed to fire impingement where we're dealing with high temperatures on the order of minutes, we now have time for gravity to start acting on those that molten material. So you can see on the these pictures we're starting to get flow of the molten material. We're getting narrow areas like on the right picture. We've got our nice little thinned out area. I'm trying to draw with the trackpad, so give me some slack here. But you can see where all that material is starting to flow just because of time is allowing this stuff to be acted on by gravity. So here's just a couple examples. Again, if you see a globule or a mass of metal that is two, three, four times the diameter of the original conductors, probably a good indicator that it was a function of... fire melting or melting by fire as opposed to arc melting. Okay so the lack of a line of demarcation is also a good indicator, probably one of the best indicators for melting by fire. You can see here these conductors, there's four of them, are melted over an area of you know at least two inches. They're severed, we've got a lot of blistering on the surface so there's really no clear line. where this damage stops and we've got pristine conductors again. You can kind of see a general area but it tends to fade away and there's not a sharp line of demarcation. You can also see this bottom conductor over here on the far left is kind of thinned out and so that would be a good indicator that we don't have any sort of electrical activity and this is from fire impingement. All right, so irregular or amorphous globules. This is a good indicator that the entire mass of the conductor was starting to be heated, and we've got gravity and time are all working on it. The big problem with melting by fire is we have to kind of remember that it's possible that we had arc melting present at some point, but now the fire impingements destroyed it. And so it's something we have to kind of keep in the back of our minds that maybe there was activity here at one point. So this isn't in 921, but it's a great indicator for examination of stranded conductors. So as my fire impinges on my conductors, these solids or these small strands in a stranded conductor are going to start to fuse together. And we essentially get one large conductor. So if you look at the top conductor, now the pictures are a little deceiving. The top one's probably the diameter of my pinky and the bottom one's probably a 16 or 18 gauge. power cord or zip cord, something like that. So the sizes are a little different, but the principle is the same. So the top one, you can kind of see on the upper left, I've still got some individual strands visible. As I move further towards the severed end, I've got a lot more blistering. I've got getting a lot less strand definition and they all basically form one solid conductor versus on the bottom. I've got, oops, I've got one. I've got this nice sharp line of demarcation here and then all the strands working back this way are in perfect shape. They're completely intact and separated and kind of free. So it's a good indicator that you know hey this is probably more arc melting on the bottom as opposed to fire impingement on top. All right so necking. This just kind of talks about how we're having mass movement or transfer as that copper, that molten copper starts to melt and flow. Now we're getting thinned areas of these conductors where the material is starting to move. It's also possible that as if I've got my conductors spanning a void space in a ceiling, maybe they're getting close to melting. And now just the physical weight of those conductors allows them to start. pulling apart so maybe they're thinning out that way but it's still melting by fire impingement. All right so alloying. This one's kind of a confusing one for a lot of people. So alloying or eutectic melting occurs when we have two different materials or at least two different materials and one the the melting temperature of one is actually you know so I'll just use copper and aluminum as an example. Aluminum has a melting temperature of around 1,200 degrees Fahrenheit. Copper is going to melt at right around 2,000 degrees Fahrenheit. So when aluminum drips onto copper, I can form an alloy that now has a lower melting temperature than either of the two. So most often what we're going to see is probably copper and aluminum alloys. Those are the ones that I see the most. The big thing here is you want to be able to see the, or you want to be able to determine where your two metals came from. So a good example on the bottom here is I've got this aluminum armored cable or a flexible conduit and right below it I've got this, I've got the copper conductors. So if I start to see alloying in this area, I can say well that should probably all be from that melted mass right there. You can see on this top conductor I've got this really nice This sounds really stupid, but I've got this nice copper color on the conductors, except for this area right here, and now they're kind of a grayish color. That's a really good indicator. The color changes are a good indicator that maybe I've got some alloying going on. So here's just a few more examples. The two pictures on the right are the same conductor, just different vantage points. But you see on the upper left we've got a definite color change from copper to this is probably a brass alloy so brass is going to melt at around 1700 degrees fahrenheit we don't have a super clear line of demarcation here it's kind of spanning you know this area here so that's a good indicator with the color change same thing here these two have some nice color changes where they're I would say a little more brassy looking. We also don't have a nice sharp line of demarcation and all of these conductors are starting to fuse together and same thing with the bottom left. They're all starting to fuse together so there's no clear line of demarcation. Right so kind of a good thing to keep in the back of your mind is this hierarchy of of melting temperatures for metals. So solder is going to melt about 350. Fahrenheit. So we're going to see that in all of our connections and circuit boards and stuff like that. Zinc is going to be about 700 degrees Fahrenheit. Aluminum is about 1200. Brass about 1700. Copper about 2000. And steel is about 2600 to 2800. So I like I grew up kind of using the the rule of 800s. So just focusing on aluminum, copper and steel. aluminum's about 800 degrees below copper, copper's about 800 degrees below steel. So just kind of an easy rule of thumb to keep in mind. Again, it's all approximate. We'll get rid of that. All right. So the big thing with the reliability of identification is, you know, again, it's all about practice. So at the end of this, You may or may not feel comfortable calling all this damage here, and this is a fully acceptable answer. But in the grand scheme of things, there's the stuff that's definitely arc melting, there's the stuff that's definitely melting by fire, and there's the gray area in the middle. Some pessimists might say that that gray area is probably the largest space, and the other two are really small. I disagree with that. You know, that's just my opinion. So the big thing is you might not know what the top of that top picture is, but this bottom one should be pretty darn obvious. And that's okay. You know, we're all able to go work to our comfort level and saying I don't know is a perfectly acceptable answer. Again, it's time tested. It's scientifically validated. The big thing is training and practice. Nobody gets good overnight. If you're an old MASH fan, you know, Charles Emerson Winchester III says, I do one thing, I do it well, and then I move on. And that's kind of, you know, how I personally feel like I got good at this was I was the one who said, all right, I'll go arc map your fire scene. I'll go look for arc melting as I grew up. That's the only way you're going to get good at this. Again, there's times where it might be ambiguous. So ultimately, you just have to chalk it up and say, I don't know, maybe you save it, mark it, give it to an engineer or metallurgist or ask an engineer or metallurgist to give you a clue or a hand. If you get to a point where you found an artifact that you can't identify, the prudent thing may be to look at that. in your analysis as it is the kind of two different scenarios. Treat it as What does it do to my analysis if it's melting by fire? And what does it do to my analysis if it's arc melting? And does that change my final hypothesis at all? There aren't too many fires that I've been to where a single artifact is going to change the whole course of the case. But, you know, it's possible, I guess. Anything's possible. So it's just a matter of kind of looking at all the different scenarios. and kind of making basing your conclusion off of that so that's that dang i got done in like 40 minutes pretty good um so now we'll uh i'll get out of this and we'll see what questions people have hey cam it's bill um just testing out a poll here people can pop onto this poll really quick And answer that while Cameron transitions over from his presentation to answer any questions. Cam, I'm going through the chat right now. Okay. I don't see that anyone has asked a question. That time really flew by for me. Not sure about you. But if anybody wants to, you can either. put it up in the chat. We have about 108 of us that have made the presentation. I'm reluctant to offer this up, but if you want to unmute yourself and just ask your question directly of Cameron, we can try that without trying to talk over each other. So we can also do that option as well. I'm going to try and stop sharing my screen so I can look at if there's any questions. Cameron, the question I have for you and the thing that I find when I'm looking at arcing, can you talk a little bit more about how building construction needs to be considered when you're interpreting where these actual arcs are found? Yeah, and I think that's probably more of like an arc fault surveying or an arc mapping question. But, you know, we can we can talk about it since we've got a little bit of time. So obviously, you have to when you're when you're looking for artifacts, you have to be kind of cognizant of factors like where's my ventilation coming from? Do I have an area of, you know, massive? We all know that ventilation is key in our fires and fire behavior. So do I have an area where I have ventilation that allows fire to burn and I have greater temperatures over in one area versus another? The other thing would be, do I have, say my fire starts in a wastebasket and then it trails across the room somehow. Maybe they've got the old dryer roll, bounced rolls of dryer sheets that it goes to the couch. Well, now. I've got a much higher heat release rate fuel in the couch than I did the garbage can. So the couch is going to have much more ability to punch through the sheetrock than the garbage can did. So I might have arc melting away from my origin because I have a higher heat release rate fuel somewhere else. You know, when we talk about building construction, obviously different types. of barriers are going to play into that. So if I've got, you know, I'm not a huge fan of suspended ceilings because if I've got one waterlogged tile, that tile could be across the room from my origin, but it's going to fall out earliest because it's already got pre-existing damage to it. Obviously, I could be removing ceiling tiles to facilitate fire spread. Well, now I'm going to have, I might have, that might be remote from my origin, but it might, I might have. preferentially arc melting over in that area due to the removed ceiling tiles or you know wood paneling is going to behave different from sheetrock which is going to behave different from lath and plaster let's see great thanks cam cam are you able to see the chat and you can you can go through and read the question yourself otherwise i can i can read it to you um yeah there is one question for me uh yes we we are recording it um I was a couple minutes late in remembering to do that, so we'll miss the first minute or two of it, but we will make it available. We will email you a link to it. And as Cam's answering this next question, I'm going to go ahead and post a link to the test. It's a 10-question test. We're going with the IAAI standard of 70% or greater. It will automatically grade it. Our secretary will get you a tested or untested certificate. for attending the course, you are going to have to copy the link out of the chat and then post it or paste it into your browser or paste it into Word so that you can go back and look at it later, but you're not going to be able to go directly to that link. So Cam, if you want to take the next question there. Yeah, so this next one is if areas of arcing are destroyed by fire damage, will there always be other evidence located on other circuits? Doubt. further down the wire etc um the answer i guess the politically correct answer would probably be it depends i would say there's not always so the probably truthful answer is no um you know it's all going to be situation dependent on how the wire the conductors are routed um again what the the building construction is like um i'm trying to see and think of something else that might Yeah, because some of these kind of get into arc mapping, which is a whole another probably hour discussion, 45 minutes to an hour discussion that we could do another time, depending on how long this coronavirus stuff drags out. I'm trying to think if there's something else that might be helpful there or might elaborate on that. Nothing that's popping into my mind. Let's see here. Next question. I don't know if this is a full question. When you see arcing many times across the fire, I don't know if that's a... Erica, you want to elaborate on that question? I'll go to the next one. You know what? I tried to. I typed it in again. Cameron, so if you go down. I'm just looking for indications of arson. So you see arcing multiple times across the fire, maybe. Is that indicative of arson versus just melting and no arcing? What are your thoughts around that? Yeah, so it's not like you can say if I find arcing, it's arson or it's not arson. We have a whole ton of electrical wiring. The majority of it is usually energized. So if it's impinged by fire when it's energized, it's usually going to leave some sort of artifact. can be you know that fire it doesn't matter if that fire is accidental or it's incendiary it just means that that conductor or those conductors or circuits were energized when fire occurred so yeah no it doesn't it doesn't play into criminal versus non-criminal or anything thank you yep all right so let's see here go to that one all right greg says does the voltage dictate the size of the mass loss or the transfer area um you I would say it probably can. So going back to like the slide where, you know, the short or the long duration versus short duration, and specifically talking about the amount of mass loss. So those two pictures, most of my tests, that was from my master's thesis research, most of my tests were at 120 volts, but then we kind of started to play with changing the voltage. a little bit just for kicks and giggles. And the long duration arcing events you saw there, where we were losing, zipping away four inches of the conductors, we're down at 30 volts. So, but again, you have to think about Ohm's law and everybody's right now shaking their head saying, no, not math. But if you remember, at a given voltage, if I keep my voltage constant and I start playing with my resistance, my current's going to fluctuate. So At a given voltage, if my current or my resistance goes down, my current's going to go up. If my resistance goes up, my current's going to go down. And the amount of current is going to dictate how quickly my circuit breaker operates. And so by having a lower current, it's going to slow my circuit breaker or my fuse down. And I potentially now have the ability to have more damage because that circuit protection device is delayed in operating. So hopefully that answered that question. Yes, it's going to be recorded. Do you get reliable artifacts when wiring is removed from conduit? I would say yes. I've, unless the wiring is, you know, it's a rip roaring fire. I've had just in January or December, I was on a huge fire out in Michigan and we had a 480 volt feeder that ran across the length of this building. The conductors were probably easily half an inch in diameter and they were in conduit, but they were completely beat to hell because they had just melted so much. So It really kind of depends on the severity of fire exposure. I really have a lot of luck examining wiring from conduit. Usually, I'm usually pretty lucky. And, you know, again, that's one of those things. It's kind of, again, an arc mapping discussion, but you really have to pull wiring from conduit. You can't just look at the exterior of the conduit and look for blowouts because I can, I rarely have arcing events that melt through the conduit. There's just not a whole lot of energy there. Most often where you're going to see those blowouts is higher voltage circuits like 480 volts. Or there's some, I've heard theories out there and I don't know of anybody who's actually tested it, where they say some types of drywall might pre-weaken the conduit and allow it to melt. I really haven't been able to verify that. But yeah, I can definitely get reliable artifacts pulling wiring from conduit if the wiring is not melted to the conduit. That does happen once in a while. Is there anything useful we can learn from trip breakers at the panel? Absolutely. So this is a again more of an arc mapping discussion. I actually if you're an IAAI member, I just got an article published in the. newest magazine that should hopefully be showing up in your mailboxes soon. But one of the things we stress in our methodology for examining a scene is we want to start on the outside and follow our circuits in, kind of like we do for most fires, but I want to follow my circuits all the way down to the location where I find a fault. And the way I do that is I start at my panel board. and I look at what breakers are tripped, and then I will kind of start with those breakers, and I will trace those circuits out until I find what caused the breaker to trip. And that way, I can kind of have a starting point for my electrical examination, and I can kind of focus it on what caused these breakers to trip. And often, that might lead me to either where my origin is, or potentially kind of help me figure out where, how the fire progressed. Let's see here. Nope, Fulton's already advertising the next class. Can arcing occur on other items than a conductor? Absolutely. So, you know, we've already talked about we could have arcing in conduit. So the other side, the other side of the arc site is potentially the conduit itself. Blowouts in conduit or excuse me, blowouts in enclosures. So we have a lot, oftentimes we'll have arcing in like panel boards where the conductors are touching the enclosure of the panel board. And so as the firearm pinches on the panel board, the insulation fails. And now I get a short or a fault between the conductors and the panel board enclosure. It's possible that, and this is going to be the really tricky one, if I have, depending on where you live and who your electrician is, the type of staple they use to secure your branch circuit cables. So if you're using non-metallic sheath cable or Romex, if you use the metal staples, which I never really saw or used until I went out east. In theory, you could have arcing from your cable to the staple as fire impinges on that cable. So then it kind of brings up the question, well, is this potentially an overdriven staple scenario that caused my fire? And obviously there's a whole lot of analysis that goes into that, but that's a possible location for arcing. I've heard of arcing, you know, where circuits run across, say, like ductwork. and they short to the ductwork. I've seen arcing to nails. What else, what else? Those are the ones that are popping into my head right now. So yes, you can have it arcing to other surfaces or conducting surfaces. Let's see here. I think that's all of them. So we only went five minutes over. I wasn't even keeping the clock, Cam. Well, I was trying. So a couple of things. If you're on Facebook, we do have a... Facebook page, Dane County Arson Response Initiative, DECARI. If you get on there tonight, and I see that we have a couple friends in common, we'll grant you access there. We do post things there. Cameron has agreed to do another class for us, same format. I only heard one time where it cut out for a couple of seconds, but otherwise I think it was pretty successful. And we're really excited about that. So April the 29th, I posted in the comments, the RSVP for that. One of the lessons that I learned here was to give you guys the password after you RSVP and not before. So that was one of the takeaways that I had from this whole experience. We also have partnered up with the Wisconsin. Department of Natural Resources. We have a forest ranger that's willing to come and talk to us on May the 20th. Also the same format. We're just trying to stay relevant to what's happening and all the social distancing and such. So right now we just have those three classes. If you have something that you would like to present in this format. Our organization would be more than willing to We'll talk to the rest of the board, but feel certain that we'd be more than happy to host that for you. We can host up to 500 people now in any one session. So if there are any other questions, if you want to unmute yourself and just talk to us directly, that would be great, or post it in the chat. The test is there, give us some feedback. We had about 170 people that RSVP'd and I think I saw up to 108. So if you know somebody that had any issues, please let us know because we're not going to be able to fix it if we don't know about it. And you had my email on the front end. So if you want or have questions, feel free to shoot me an email at the risk of having my inbox blow up. I'm always available to answer questions. So, yeah, thanks, Bill. I just posted Cameron's email. I guess I'll go ahead and post mine too, just to make it. This is an official government email address, so be careful what you send to that one, please. The government is watching. They're definitely watching. So, anybody want to unmute yourself and say anything? We really appreciate everybody giving us the kudos here in the chat. You know, like I said, you know, we're in a... in different times now. So we're, we're trying to keep up with the times and stay relevant. So we really appreciate everybody taking the time out, um, to meet with us and, and do this format. Cameron, I really appreciate it, buddy. And I've already suckered you into, uh, to doing it again. So, and I appreciate you, uh, your willingness to do that for us. Certainly. So I'm going to go ahead and end the recording right now. So.

Just about everything has been debunked. So there's nothing reliable at this point in time. But I think there is some current research right now in the works that's being reviewed.

So we'll see where that ends up. Terminology wise, a little bit of a pet peeve of mine. Kind of want to go through this first.

So the one thing that kind of drives me nuts when we're working out on fire scenes is people say, well, we got to go look for arcs. and unless your fire scene is still energized you're not going to find any arcs on your scene because the arc per 921 is the actual discharge from some sort of electrical fault or maybe it's a an intentional thing or a switch opening or closing so the arc is the actual discharge that will cause our anomalies on our wiring 921 refers to an arc site as the location with the damage caused by an arc a bead is defined as a rounded globule of re-solidified metal. What I don't like about this definition is it says it's on the ends of the remains of a conductor, which, like I said, you can see at the bottom here, insinuates that every arcing event results in the conductor or conductors being severed, which is definitely not the case.

I think I put in a proposal for this next edition of 921 coming out this summer. They did tweak that to say metal on the remains instead of at the end of the remains. And then I think they added conductor or conductors.

One of the other proposals that I put in was for this definition here. And that was just a generic arc melting definition. So that because the other problem with a bead is it's really just a characteristic of evidence of arcing.

And so this arc melting definition kind of encapsulates. everything, all the characteristics of arcing that are presented in 921. And so I believe that was accepted by the committee and will be in the next edition as well. All right.

So I'm not going to read through all this. It's just kind of up there for your benefit. One of the first things I like to throw out here though is the very first sentence says abnormal electrical activity will usually produce characteristic damage. And outside of my full presentations that I give, one of the things I really like to stress is that in order to know how something might fail, you have to know how it works under normal circumstances. So in order to know what abnormal electrical activity is, you better know what normal electrical activity is.

The big thing about when we talk about damage on electrical systems is there really are no absolutes and there's a lot of times or there are maybe not a lot there are some times where you're not going to be able to make some sort of conclusion and you just have to throw your hands up and say I don't know which is perfectly acceptable. I try and make people in my classes get used to saying I don't know a lot because it really does happen and nobody should be ashamed of that. So 921. The 2017 edition, and as far as I know, the 2020 edition isn't going to change any of these, lists all these characteristics for arc melting. And I'm going to focus on all of them but the last two, because those are ones that are readily available or can be easily seen on a fire scene by you or myself or anybody else, unless their eyesight's really poor.

but you can see all these without the aid of some specialized equipment. Maybe you get a little magnifying glass or something like that, but these last two are going to be something that you're probably going to need a metallurgist for. So we're going to go through these one by one and just go through some photos. The first characteristic of the cables, we had a researcher from Japan at the Fire Research Lab years ago when I was an intern there.

And he basically copied my research for my master's thesis and did the same thing with Japanese cables. And so we found that, lo and behold, arc melting looks the same in Japan as it does in the United States. So the question or the thing that kind of, I think, will help an investigator most often when they're...

looking at this type of damage is asking themselves how is it that a fire could do this limited damage to a cable or conductor like this so you can see in the bottom left We've got very pristine wiring. I'll see if I can, I'm not going to bother, I'll screw it up and see if I could get a pointer. But you'll see there's lines that run the length of the conductor from side to side.

We've got a very sharp line of demarcation. Oops, go back. We've got a sharp line of demarcation where, you know, the conductor's pristine condition and then it's melted. And in fact, the two adjacent areas of damage from the arcing are on the most protected areas of the conductors because they're in between the two conductors. So there's nothing but insulation in between there.

Fire is not precise enough to create this like one or two millimeters sized jet to punch in between two conductors and cause melting to occur. So that's just one way to go about kind of the mental exercise of. trying to identify this type of damage. Okay, again, this is a, I'm not a huge fan of using a single conductor, but sometimes that might be all you have, because maybe you pull a conductor out of conduit, and the other side of the arc site is the conduit itself, and nobody has the time, nor usually the equipment, to section conduit from end to end to find the arc site on the inside. So, but I know this was an arc. or an arc melting created by arcing because it was a lab generated or a test burn.

So I know that for a fact it's what it is, but you can see very pristine conductor up until the area of the damage, and then it's pristine beyond that. You can kind of see some longitudinal lines here, and I'll get to those in a little bit. It's a later characteristic, but it's something to kind of keep in the back of your mind.

um, when a liquid or all liquids have some sort of surface tension to them. And because of that, they like to form round shapes and molten copper is no different. So when we melt copper like this, it's going to create these beads. And, uh, which, and so that's a good characteristic to look at. Um, they're very nice and smooth.

You can almost see spatter or, um, almost like, uh, all the waves, you know, waves like a liquid wave expanding or radiating out from the arc site. Those are good indicators that this is, was molten for a short period of time. The, again going back to that first slide, this is a non-metallic sheath cable or commonly called Romex is the, a brand name, and this was from a test burn and in this case the hot or the ungrounded conductor is on the top, the ground is in the middle, and the neutral is on the bottom. So going back to the first slide, how is it that fire impingement is going to be so localized and focused that it's going to melt two out of the three conductors and leave the third conductor that's a millimeter away completely undamaged? Again, it's just kind of repeating the same question over and over.

There's no way that fire is going to be this precise. Okay, and again, a localized point of contact. So these conductors, it's the same setup. This is another test burn. Hot conductors on the top, ground in the middle, neutral on the bottom.

A very, generally a very localized area of damage, usually where the two conductors are closest together. Occasionally we get all three conductors involved. That's not unheard of. Let's see here. Keep on going.

Again, the corresponding areas of damage. These were lab tests. So hot conductor on the top, ground in the middle, neutral on the bottom. Again, I only touched two out of the three conductors. One thing you'll notice on both of these, there is a bead or a rounded shape on one and a notch or a little bite taken out of the other conductor.

So good terms to use when describing arc melting. and things to look for are mass loss and mass transfer. So you can see on the picture on the left, I've got mass loss on the hot conductor on top, and I've got mass transfer from that hot conductor to the ground in the middle.

And I've also got it kind of spread around the perimeter of that or the circumference of that top conductor. And the same thing on the right side. I've got a nice bead on the top conductor and a notch taken out of the ground.

And that's just, it's the... The direction that mass travels or material travels is kind of a function of which direction the electrons are flowing at any given time because it's alternating current. We're changing the direction of current flow which means we're changing the direction of our electron flow. So that's where our how our mass moves when something like this happens. Resolidification waves, that's the the phrase I was looking for earlier.

So again because these are molten and it cools very quickly we can freeze these waves in the metal. These were lab generated artifacts. On the left we took these pictures under a scanning electron microscope and then we tried to recreate the same image under a regular microscope on the right. So you can see the mass loss on the upper conductor and then it was transferred to the middle ground conductor. So these can be quite obvious at times and sometimes not so much, you know, but if you find them it should be a pretty good indicator that you've got arcing going on.

So when I talked about those longitudinal lines earlier, I was referring to these copper drawing lines. And the way copper wiring is made is you take a blank or a block or a cylinder of copper and you draw it through successively smaller dies until it gets to the proper diameter. And because you're pulling it through these dies, you're creating tool marks on the surface of those conductors. And those tool marks, you can see here, these longitudinal lines running the length of the conductor, they're scratches or tool marks, whatever you want to call them. If you still see these on your conductors, they are probably the most, probably one of the best indicators that your conductor wasn't on the verge of melting by fire impingement.

Because fire is going to be melting the entire mass of that conductor. And because these are so minute. they should be one of the first characteristics that are obliterated by fire impingement. So given that, if you still have them and like here you can see they're intact up to the area of my cursor, I'll see if I can do this, you can see them up to the area of damage and then they just completely are obliterated because of the arc melting.

So that's something to keep in mind. Again, like you see in the bottom bullet point here, if they're not present, that's a very good indicator that the entire conductor is starting to melt, possibly from fire impingement. There we go. All right, so small beads and divots.

It's possible that we might not have a super localized area of damage because we either have arcing through char or whatever. delayed activation of a circuit breaker or fuse. I should say that delay is usually a result from either arcing through char or we have maybe some resistance.

I'm getting all mixed up myself. We either have lower voltages or we have a we don't have a low resistance fault so maybe I'm conducting through some charred insulation. So it's not a low resistance fault.

So because I don't have a low resistance, my current is not as high, which means my circuit breaker or my fuse doesn't react as quickly. Nick Carey over in London or in the UK did his doctoral dissertation on arcing and arc mapping and the damage produced. And he referred to this as arcing through char because, and he kind of, one of the descriptors he used was basically a sandpaper type feel. So it's not a typical notch and bead kind of scenario. It was more very fine damage that the surface of the conductor was slightly melted, but didn't have a ton of mass loss.

Okay, so this isn't in 921, but it's still a good indicator in that arcing is an explosion. And so based on the severity of that explosion, we're going to be expelling. material or mass from that fault location.

And fire is not going to allow the laws of gravity to take a break. And the molten metal is not going to go upwards if it's melting by fire impingement. So these sparks are ejected when an arc occurs and that blows material in all directions.

So if you find a location of melting, and you've got spatter on the enclosure or somewhere up above, probably a good indicator it wasn't melting by fire because these molten particles are not going to... defy the laws of gravity. One thing I'll just, I might be getting ahead of myself, but I, because I'm using the terminology, one thing that, actually, no, I'll come back to it in a few slides. Never mind.

Instructor's getting ahead of himself. Sprayed particles. Like I said, mass transfer is a good term. You can see here, I've got, it's a meter socket, and the three jaws on top, which they're kind of cut off a little bit, are intact.

The lower left jaw is intact. but then the two on the lower right and in the middle, bottom middle, are both missing a lot of material. So, again, good indicators that I've got some sort of damage there that I need to look at. Okay, so one thing you'll have noticed, or hopefully you'll have noticed as you go through these pictures, is that each picture doesn't necessarily just have one characteristic.

A lot of them have more than one characteristic. So the fact that you have more than one should help you in coming to a conclusion as to what am I dealing with here. But there is no requirement that you have to have every single characteristic present in order to identify an artifact.

So this is here. I won't go through every one of these because every definition is the same. But what I wanted to show is that.

Since 2008 up till now and I believe 2020, the definition of a bead other than the slight change that I proposed as far as on the remains hasn't changed. And you'll see that a bead by definition is created by an arcing event. There was a paper published in 2012 that was submitted to the 921 committee.

that basically said that beads caused by fire impingement and arc melting or arcing were visually indistinguishable. And the problem with that paper is obviously they're using the incorrect terminology. A bead by definition in 921 is an electrical caused event or artifact. And I like to use the term globule to refer to you know molten material caused by melting by fire. There were some other issues with that paper.

Largely, they were testing methodology issues that weren't consistent with what we'd see in a fire. So what I kind of wanted to throw in here or throw this in here is there's a paper out there. You may see it someday in court or have it thrown around by a defense expert or an opposing party.

And that paper was not accepted in the 921. So if you ever see that, you can kind of take a look at and say, well. the testing methodology is not the best and it wasn't adopted into 921. All right, so factors that are going to influence how much damage we have from an arc are going to include the length of the circuit, the size of the wire, the conductors, the voltage that the system's running at, so if it's a regular 120 volt system versus maybe it's a low voltage system of 30 volts, and then the resistance at the faulting location. Those are all going to play into how much current is allowed to flow at the fault, which is going to dictate how long it takes for that circuit breaker or fuse to operate.

And the reason why that's important is whether or not we have a long duration versus a short duration arcing event. So long duration, we're going to have more mass loss and short duration, we're going to have less mass loss. You'll see, again, another kind of nitpicky terminology thing. Some in the electrical engineering world, they like to use a long-duration arcing event they refer to as an arc, and a short-duration arcing event they refer to as a spark. I really don't like those definitions because, to me, an arc is an arc, and all I'm doing is putting a, is it long-duration or short-duration?

And for the most part, we usually don't really know. because we're looking at it after the fact. We're not there to watch it. So I just like to use it's either long duration or short duration.

Furthermore, 921 talks about an arc as being the actual discharge, and a spark is a particle that's glowing, and it's either glowing because it's so hot that it's glowing, meaning it's probably around 1,000 degrees Fahrenheit or higher, or it has combustion. occurring on its surface. So sparks in my world, I like to think of them. I like to keep things simple. A spark is if I arc two wires together, the particles that fly away, the mass loss.

are the sparks or I can have sparks from welding or grinding or cutting. Those are all, you know, the ignition handbook refers to those as mechanical sparks because it's a physical particle. So I think I beat that enough.

So just kind of an example of a short duration arcing event. This is a lab generated artifact, hot conductor on the top, ground in the middle, neutral on the bottom. So you can see I've got very localized damage.

I ended up severing one conductor. And what we did was we measured the voltage and the current. And this was an open circuit, so no current was flowing until we had enough charred insulation that current was able to punch through and create a fault.

So you'll see we've got a nice sinusoidal waveform, no current flow. And then at some point, the current shoots up to over 450 amps, trips the circuit breaker, stops the arc, and... a little bit less than half a cycle, no more current flow, no more voltage. So that's a short duration arcing event. Long duration arcing event, like this one, same type of test, but you see now we only have one conductor left, that's the neutral conductor.

We've completely zipped away and vaporized two out of the three conductors, there's about four inches of conductor missing there, a little bit less. Again, how is fire going to melt, selectively melt? two out of the three conductors there's really no way and you can see in the the diet or the waveforms we've got voltage and current flow and we've got a long duration arcing event this one I only have a portion of the waveforms and we're only getting about it's at least a quarter of a second of arcing as opposed to that fraction of a cycle before so what causes arc melting or arcing probably could have let off with this, but what happens is our insulation breaks down on our conductors, and this can be a function of either fire impingement or it could have been separate from fire.

So this is one of the reasons why I kind of dislike the direction 921's going, and that they're referring to arc mapping as a fire pattern, because in my opinion, by saying arc mapping is a fire pattern, you're automatically assuming that every arc site that you find caused by fire impingement and we don't really know that until we look at them all and figure out what what the context is. But so that's just my opinion. So when we get arcing caused by fire impingement we call it arcing through char. So heat's damaging the insulation.

That insulation becomes a temperature dependent semiconductor meaning the higher the temperature goes the better of a conductor it is and if I lower the temperature it actually becomes a worse conductor. and we're going to get to a point where we're able to actually sustain current flow and it just punches through the last atom that's intact and now we have a fault. 921 talks about arc tracking and arcing through char that defines them both. So arc tracking is when we have electricity flowing across the surface of a conductor or an insulator.

That's usually because we've got insulator corrosion We've got some contaminants, we've got moisture or all of the above or a mixture of the above. And then arcing through char is we have some sort of external heating that breaks down the insulation. So arc tracking kind of is the electricity is causing the carbonized path, arcing through char is external heat causing the carbonized path.

Alright, so that's all the electrical caused stuff. Now let's get into the fire caused stuff. we're going to focus on the first three because those are the ones we can see without any fancy instrumentation or chemicals or supplies. So the first one is the effects of gravity.

So arcing is very quick. A circuit breaker, if used as supposed to under normal circumstances, stop that arc very quickly. Therefore the molten metal is going to cool down quickly and it's going to be kind of frozen in time and gravity is not really going to usually have time to work on it.

as opposed to fire impingement where we're dealing with high temperatures on the order of minutes, we now have time for gravity to start acting on those that molten material. So you can see on the these pictures we're starting to get flow of the molten material. We're getting narrow areas like on the right picture. We've got our nice little thinned out area.

I'm trying to draw with the trackpad, so give me some slack here. But you can see where all that material is starting to flow just because of time is allowing this stuff to be acted on by gravity. So here's just a couple examples. Again, if you see a globule or a mass of metal that is two, three, four times the diameter of the original conductors, probably a good indicator that it was a function of...

fire melting or melting by fire as opposed to arc melting. Okay so the lack of a line of demarcation is also a good indicator, probably one of the best indicators for melting by fire. You can see here these conductors, there's four of them, are melted over an area of you know at least two inches.

They're severed, we've got a lot of blistering on the surface so there's really no clear line. where this damage stops and we've got pristine conductors again. You can kind of see a general area but it tends to fade away and there's not a sharp line of demarcation. You can also see this bottom conductor over here on the far left is kind of thinned out and so that would be a good indicator that we don't have any sort of electrical activity and this is from fire impingement. All right, so irregular or amorphous globules.

This is a good indicator that the entire mass of the conductor was starting to be heated, and we've got gravity and time are all working on it. The big problem with melting by fire is we have to kind of remember that it's possible that we had arc melting present at some point, but now the fire impingements destroyed it. And so it's something we have to kind of keep in the back of our minds that maybe there was activity here at one point. So this isn't in 921, but it's a great indicator for examination of stranded conductors.

So as my fire impinges on my conductors, these solids or these small strands in a stranded conductor are going to start to fuse together. And we essentially get one large conductor. So if you look at the top conductor, now the pictures are a little deceiving.

The top one's probably the diameter of my pinky and the bottom one's probably a 16 or 18 gauge. power cord or zip cord, something like that. So the sizes are a little different, but the principle is the same. So the top one, you can kind of see on the upper left, I've still got some individual strands visible.

As I move further towards the severed end, I've got a lot more blistering. I've got getting a lot less strand definition and they all basically form one solid conductor versus on the bottom. I've got, oops, I've got one. I've got this nice sharp line of demarcation here and then all the strands working back this way are in perfect shape. They're completely intact and separated and kind of free.

So it's a good indicator that you know hey this is probably more arc melting on the bottom as opposed to fire impingement on top. All right so necking. This just kind of talks about how we're having mass movement or transfer as that copper, that molten copper starts to melt and flow.

Now we're getting thinned areas of these conductors where the material is starting to move. It's also possible that as if I've got my conductors spanning a void space in a ceiling, maybe they're getting close to melting. And now just the physical weight of those conductors allows them to start. pulling apart so maybe they're thinning out that way but it's still melting by fire impingement.

All right so alloying. This one's kind of a confusing one for a lot of people. So alloying or eutectic melting occurs when we have two different materials or at least two different materials and one the the melting temperature of one is actually you know so I'll just use copper and aluminum as an example.

Aluminum has a melting temperature of around 1,200 degrees Fahrenheit. Copper is going to melt at right around 2,000 degrees Fahrenheit. So when aluminum drips onto copper, I can form an alloy that now has a lower melting temperature than either of the two. So most often what we're going to see is probably copper and aluminum alloys.

Those are the ones that I see the most. The big thing here is you want to be able to see the, or you want to be able to determine where your two metals came from. So a good example on the bottom here is I've got this aluminum armored cable or a flexible conduit and right below it I've got this, I've got the copper conductors.

So if I start to see alloying in this area, I can say well that should probably all be from that melted mass right there. You can see on this top conductor I've got this really nice This sounds really stupid, but I've got this nice copper color on the conductors, except for this area right here, and now they're kind of a grayish color. That's a really good indicator. The color changes are a good indicator that maybe I've got some alloying going on.

So here's just a few more examples. The two pictures on the right are the same conductor, just different vantage points. But you see on the upper left we've got a definite color change from copper to this is probably a brass alloy so brass is going to melt at around 1700 degrees fahrenheit we don't have a super clear line of demarcation here it's kind of spanning you know this area here so that's a good indicator with the color change same thing here these two have some nice color changes where they're I would say a little more brassy looking. We also don't have a nice sharp line of demarcation and all of these conductors are starting to fuse together and same thing with the bottom left. They're all starting to fuse together so there's no clear line of demarcation.

Right so kind of a good thing to keep in the back of your mind is this hierarchy of of melting temperatures for metals. So solder is going to melt about 350. Fahrenheit. So we're going to see that in all of our connections and circuit boards and stuff like that. Zinc is going to be about 700 degrees Fahrenheit. Aluminum is about 1200. Brass about 1700. Copper about 2000. And steel is about 2600 to 2800. So I like I grew up kind of using the the rule of 800s.

So just focusing on aluminum, copper and steel. aluminum's about 800 degrees below copper, copper's about 800 degrees below steel. So just kind of an easy rule of thumb to keep in mind.

Again, it's all approximate. We'll get rid of that. All right. So the big thing with the reliability of identification is, you know, again, it's all about practice.

So at the end of this, You may or may not feel comfortable calling all this damage here, and this is a fully acceptable answer. But in the grand scheme of things, there's the stuff that's definitely arc melting, there's the stuff that's definitely melting by fire, and there's the gray area in the middle. Some pessimists might say that that gray area is probably the largest space, and the other two are really small. I disagree with that.

You know, that's just my opinion. So the big thing is you might not know what the top of that top picture is, but this bottom one should be pretty darn obvious. And that's okay.

You know, we're all able to go work to our comfort level and saying I don't know is a perfectly acceptable answer. Again, it's time tested. It's scientifically validated.

The big thing is training and practice. Nobody gets good overnight. If you're an old MASH fan, you know, Charles Emerson Winchester III says, I do one thing, I do it well, and then I move on. And that's kind of, you know, how I personally feel like I got good at this was I was the one who said, all right, I'll go arc map your fire scene. I'll go look for arc melting as I grew up.

That's the only way you're going to get good at this. Again, there's times where it might be ambiguous. So ultimately, you just have to chalk it up and say, I don't know, maybe you save it, mark it, give it to an engineer or metallurgist or ask an engineer or metallurgist to give you a clue or a hand.

If you get to a point where you found an artifact that you can't identify, the prudent thing may be to look at that. in your analysis as it is the kind of two different scenarios. Treat it as What does it do to my analysis if it's melting by fire? And what does it do to my analysis if it's arc melting? And does that change my final hypothesis at all?

There aren't too many fires that I've been to where a single artifact is going to change the whole course of the case. But, you know, it's possible, I guess. Anything's possible. So it's just a matter of kind of looking at all the different scenarios. and kind of making basing your conclusion off of that so that's that dang i got done in like 40 minutes pretty good um so now we'll uh i'll get out of this and we'll see what questions people have hey cam it's bill um just testing out a poll here people can pop onto this poll really quick And answer that while Cameron transitions over from his presentation to answer any questions.

Cam, I'm going through the chat right now. Okay. I don't see that anyone has asked a question.

That time really flew by for me. Not sure about you. But if anybody wants to, you can either.

put it up in the chat. We have about 108 of us that have made the presentation. I'm reluctant to offer this up, but if you want to unmute yourself and just ask your question directly of Cameron, we can try that without trying to talk over each other.

So we can also do that option as well. I'm going to try and stop sharing my screen so I can look at if there's any questions. Cameron, the question I have for you and the thing that I find when I'm looking at arcing, can you talk a little bit more about how building construction needs to be considered when you're interpreting where these actual arcs are found? Yeah, and I think that's probably more of like an arc fault surveying or an arc mapping question. But, you know, we can we can talk about it since we've got a little bit of time.

So obviously, you have to when you're when you're looking for artifacts, you have to be kind of cognizant of factors like where's my ventilation coming from? Do I have an area of, you know, massive? We all know that ventilation is key in our fires and fire behavior. So do I have an area where I have ventilation that allows fire to burn and I have greater temperatures over in one area versus another? The other thing would be, do I have, say my fire starts in a wastebasket and then it trails across the room somehow.

Maybe they've got the old dryer roll, bounced rolls of dryer sheets that it goes to the couch. Well, now. I've got a much higher heat release rate fuel in the couch than I did the garbage can. So the couch is going to have much more ability to punch through the sheetrock than the garbage can did.

So I might have arc melting away from my origin because I have a higher heat release rate fuel somewhere else. You know, when we talk about building construction, obviously different types. of barriers are going to play into that.

So if I've got, you know, I'm not a huge fan of suspended ceilings because if I've got one waterlogged tile, that tile could be across the room from my origin, but it's going to fall out earliest because it's already got pre-existing damage to it. Obviously, I could be removing ceiling tiles to facilitate fire spread. Well, now I'm going to have, I might have, that might be remote from my origin, but it might, I might have.

preferentially arc melting over in that area due to the removed ceiling tiles or you know wood paneling is going to behave different from sheetrock which is going to behave different from lath and plaster let's see great thanks cam cam are you able to see the chat and you can you can go through and read the question yourself otherwise i can i can read it to you um yeah there is one question for me uh yes we we are recording it um I was a couple minutes late in remembering to do that, so we'll miss the first minute or two of it, but we will make it available. We will email you a link to it. And as Cam's answering this next question, I'm going to go ahead and post a link to the test.

It's a 10-question test. We're going with the IAAI standard of 70% or greater. It will automatically grade it. Our secretary will get you a tested or untested certificate. for attending the course, you are going to have to copy the link out of the chat and then post it or paste it into your browser or paste it into Word so that you can go back and look at it later, but you're not going to be able to go directly to that link.

So Cam, if you want to take the next question there. Yeah, so this next one is if areas of arcing are destroyed by fire damage, will there always be other evidence located on other circuits? Doubt. further down the wire etc um the answer i guess the politically correct answer would probably be it depends i would say there's not always so the probably truthful answer is no um you know it's all going to be situation dependent on how the wire the conductors are routed um again what the the building construction is like um i'm trying to see and think of something else that might Yeah, because some of these kind of get into arc mapping, which is a whole another probably hour discussion, 45 minutes to an hour discussion that we could do another time, depending on how long this coronavirus stuff drags out.

I'm trying to think if there's something else that might be helpful there or might elaborate on that. Nothing that's popping into my mind. Let's see here. Next question. I don't know if this is a full question.

When you see arcing many times across the fire, I don't know if that's a... Erica, you want to elaborate on that question? I'll go to the next one.

You know what? I tried to. I typed it in again.

Cameron, so if you go down. I'm just looking for indications of arson. So you see arcing multiple times across the fire, maybe. Is that indicative of arson versus just melting and no arcing?

What are your thoughts around that? Yeah, so it's not like you can say if I find arcing, it's arson or it's not arson. We have a whole ton of electrical wiring.

The majority of it is usually energized. So if it's impinged by fire when it's energized, it's usually going to leave some sort of artifact. can be you know that fire it doesn't matter if that fire is accidental or it's incendiary it just means that that conductor or those conductors or circuits were energized when fire occurred so yeah no it doesn't it doesn't play into criminal versus non-criminal or anything thank you yep all right so let's see here go to that one all right greg says does the voltage dictate the size of the mass loss or the transfer area um you I would say it probably can.

So going back to like the slide where, you know, the short or the long duration versus short duration, and specifically talking about the amount of mass loss. So those two pictures, most of my tests, that was from my master's thesis research, most of my tests were at 120 volts, but then we kind of started to play with changing the voltage. a little bit just for kicks and giggles. And the long duration arcing events you saw there, where we were losing, zipping away four inches of the conductors, we're down at 30 volts.

So, but again, you have to think about Ohm's law and everybody's right now shaking their head saying, no, not math. But if you remember, at a given voltage, if I keep my voltage constant and I start playing with my resistance, my current's going to fluctuate. So At a given voltage, if my current or my resistance goes down, my current's going to go up.

If my resistance goes up, my current's going to go down. And the amount of current is going to dictate how quickly my circuit breaker operates. And so by having a lower current, it's going to slow my circuit breaker or my fuse down.

And I potentially now have the ability to have more damage because that circuit protection device is delayed in operating. So hopefully that answered that question. Yes, it's going to be recorded.

Do you get reliable artifacts when wiring is removed from conduit? I would say yes. I've, unless the wiring is, you know, it's a rip roaring fire. I've had just in January or December, I was on a huge fire out in Michigan and we had a 480 volt feeder that ran across the length of this building. The conductors were probably easily half an inch in diameter and they were in conduit, but they were completely beat to hell because they had just melted so much.

So It really kind of depends on the severity of fire exposure. I really have a lot of luck examining wiring from conduit. Usually, I'm usually pretty lucky. And, you know, again, that's one of those things. It's kind of, again, an arc mapping discussion, but you really have to pull wiring from conduit.

You can't just look at the exterior of the conduit and look for blowouts because I can, I rarely have arcing events that melt through the conduit. There's just not a whole lot of energy there. Most often where you're going to see those blowouts is higher voltage circuits like 480 volts. Or there's some, I've heard theories out there and I don't know of anybody who's actually tested it, where they say some types of drywall might pre-weaken the conduit and allow it to melt.

I really haven't been able to verify that. But yeah, I can definitely get reliable artifacts pulling wiring from conduit if the wiring is not melted to the conduit. That does happen once in a while.

Is there anything useful we can learn from trip breakers at the panel? Absolutely. So this is a again more of an arc mapping discussion. I actually if you're an IAAI member, I just got an article published in the.

newest magazine that should hopefully be showing up in your mailboxes soon. But one of the things we stress in our methodology for examining a scene is we want to start on the outside and follow our circuits in, kind of like we do for most fires, but I want to follow my circuits all the way down to the location where I find a fault. And the way I do that is I start at my panel board. and I look at what breakers are tripped, and then I will kind of start with those breakers, and I will trace those circuits out until I find what caused the breaker to trip. And that way, I can kind of have a starting point for my electrical examination, and I can kind of focus it on what caused these breakers to trip.

And often, that might lead me to either where my origin is, or potentially kind of help me figure out where, how the fire progressed. Let's see here. Nope, Fulton's already advertising the next class.

Can arcing occur on other items than a conductor? Absolutely. So, you know, we've already talked about we could have arcing in conduit.

So the other side, the other side of the arc site is potentially the conduit itself. Blowouts in conduit or excuse me, blowouts in enclosures. So we have a lot, oftentimes we'll have arcing in like panel boards where the conductors are touching the enclosure of the panel board.

And so as the firearm pinches on the panel board, the insulation fails. And now I get a short or a fault between the conductors and the panel board enclosure. It's possible that, and this is going to be the really tricky one, if I have, depending on where you live and who your electrician is, the type of staple they use to secure your branch circuit cables. So if you're using non-metallic sheath cable or Romex, if you use the metal staples, which I never really saw or used until I went out east. In theory, you could have arcing from your cable to the staple as fire impinges on that cable.

So then it kind of brings up the question, well, is this potentially an overdriven staple scenario that caused my fire? And obviously there's a whole lot of analysis that goes into that, but that's a possible location for arcing. I've heard of arcing, you know, where circuits run across, say, like ductwork. and they short to the ductwork. I've seen arcing to nails.

What else, what else? Those are the ones that are popping into my head right now. So yes, you can have it arcing to other surfaces or conducting surfaces. Let's see here. I think that's all of them.

So we only went five minutes over. I wasn't even keeping the clock, Cam. Well, I was trying. So a couple of things.

If you're on Facebook, we do have a... Facebook page, Dane County Arson Response Initiative, DECARI. If you get on there tonight, and I see that we have a couple friends in common, we'll grant you access there. We do post things there. Cameron has agreed to do another class for us, same format.

I only heard one time where it cut out for a couple of seconds, but otherwise I think it was pretty successful. And we're really excited about that. So April the 29th, I posted in the comments, the RSVP for that. One of the lessons that I learned here was to give you guys the password after you RSVP and not before. So that was one of the takeaways that I had from this whole experience.

We also have partnered up with the Wisconsin. Department of Natural Resources. We have a forest ranger that's willing to come and talk to us on May the 20th. Also the same format.

We're just trying to stay relevant to what's happening and all the social distancing and such. So right now we just have those three classes. If you have something that you would like to present in this format.

Our organization would be more than willing to We'll talk to the rest of the board, but feel certain that we'd be more than happy to host that for you. We can host up to 500 people now in any one session. So if there are any other questions, if you want to unmute yourself and just talk to us directly, that would be great, or post it in the chat.

The test is there, give us some feedback. We had about 170 people that RSVP'd and I think I saw up to 108. So if you know somebody that had any issues, please let us know because we're not going to be able to fix it if we don't know about it. And you had my email on the front end.

So if you want or have questions, feel free to shoot me an email at the risk of having my inbox blow up. I'm always available to answer questions. So, yeah, thanks, Bill. I just posted Cameron's email.

I guess I'll go ahead and post mine too, just to make it. This is an official government email address, so be careful what you send to that one, please. The government is watching. They're definitely watching. So, anybody want to unmute yourself and say anything?

We really appreciate everybody giving us the kudos here in the chat. You know, like I said, you know, we're in a... in different times now. So we're, we're trying to keep up with the times and stay relevant. So we really appreciate everybody taking the time out, um, to meet with us and, and do this format.

Cameron, I really appreciate it, buddy. And I've already suckered you into, uh, to doing it again. So, and I appreciate you, uh, your willingness to do that for us.

Certainly. So I'm going to go ahead and end the recording right now. So.

Transcript for:Understanding Fire Scene Electrical Damage

Transcript for:
Understanding Fire Scene Electrical Damage