Overview
This lecture covers NEC 2020 Article 110.14, focusing on electrical terminals, terminal limitations, conductor types, splicing, temperature ratings, and proper torque application for electrical equipment connections.
Electrical Connections: Terminals & Splicing
- Use terminals and splicing connectors identified for the specific conductor metal (e.g., copper or aluminum).
- Do not mix dissimilar metals (like copper and aluminum) in a terminal unless specifically identified for both.
- Optional materials like solder, flux, inhibitors, or compounds must not damage conductors/equipment and must be suitable for use.
- For finely stranded conductors (more than Class B), only use terminals identified for the specific stranding class.
Termination Methods
- Connections must ensure good contact without damaging conductors; acceptable means include pressure connectors, set screws, solder, or splices.
- Wire binding screws or studs with upturned lugs are permitted for 10 AWG or smaller conductors.
- Terminals for more than one conductor or for aluminum must be clearly identified as such.
Splices
- Conductors must be spliced with devices identified for the purpose, or by brazing, welding, or soldering.
- Soldered splices must be first mechanically and electrically secured, then insulated equivalently to the conductor.
- Listed direct burial connectors are required for splices in direct burial applications.
Temperature Limitations
- The ampacity (current capability) of a conductor is limited by the lowest temperature rating among connected devices, terminals, and conductors.
- Conductors with higher temperature ratings can be used for ampacity adjustment/correction, but never exceed the weakest component's temperature rating.
Equipment Rating 100A or Less, or 14–1 AWG
- Use ampacity from the 60°C column unless equipment and conductors are rated higher.
- If all components are rated 75°C, use the 75°C ampacity value.
- For motors marked B, C, or D, use 75°C-rated conductors if terminals are so identified.
Equipment Over 100A or Larger than 1 AWG
- Generally, use the 75°C ampacity column unless equipment is marked for higher.
- 90°C-rated conductors can be used for adjustments/corrections but ampacity must not exceed 75°C limits unless terminals are rated higher.
Torque for Terminal Connections
- Tightening torque must match manufacturer’s instructions or equipment labeling.
- Approved means (e.g., torque wrenches, shear bolt devices) should be used for proper torque.
- If torque values are missing, refer to manufacturer or NEC Informative Annex I for guidance.
Key Terms & Definitions
- Ampacity — Maximum current a conductor can carry without overheating.
- Terminal — Point where conductors are connected to equipment.
- Pressure Connector — Device using pressure to secure a conductor (e.g., set screw).
- Splicing Connector — Device that joins conductors together.
- Temperature Rating — Maximum sustained temperature a component or conductor can handle.
- AHJ — Authority Having Jurisdiction (e.g., inspector).
Action Items / Next Steps
- Review NEC Table 310.16 and NEC Section 310.12 for ampacity references.
- Consult manufacturer documentation for specific torque values when not present on equipment.
- Prepare for exam questions on terminal temperature limitations and conductor sizing.