NEC Wiring Methods Lecture

Introduction

Wiring Methods: Only those recognized by the National Electrical Code (NEC) can be installed in buildings or occupancies.
Chapter 3: Covers wiring methods and materials.

Article 300: General wiring methods requirements.
Article 310: Conductors.
Various Articles: Cover different cable types and methods.
Key concept: Chapter 3 dictates which wiring methods are permitted.
Important Point: Example provided of a commercial building with unrecognized fittings shows a code violation.
- Electrical piping used was not recognized by the Code.
- Safety considerations are crucial.

Article 352: PVC Conduit
- 352.6 Scope: PVC conduit, elbows, and fittings must be listed.
- 300.15 Fittings: Fittings must be designed for the specific Raceway.
- 110.12: Addresses poor job and execution.
- 352.24a Bends: Bends must not damage the conduit or reduce its internal diameter. Must be made with appropriate equipment.
Table 2 Chapter 9: Defines radius for bends in conduits.
- Example: Half-inch radius is 4 inches.

Graphic Example: Commercial building with poor wiring methods, leading to potential safety hazards and NEC violations.
- Issues include using unlisted fittings and improper bends.
Avoiding Violations: Importance of following the code for installations to ensure safety and compliance.

Service Life and Safety: Incorrect installations can lead to system failures and safety issues.
- Example: Wiring in-ground with weatherproof boxes, prone to filling with water, causing splices to malfunction.
Consideration for future service: Proper installation considers future maintenance and safety of others.
- Example: Replaced a $40,000 generator due to faulty low-voltage lighting installation by a homeowner.

Proper adherence to NEC wiring methods is critical for safety and system reliability.
Consideration of others and future maintenance is vital in initial installations.