NEC Article 402 details the requirements for fixture wires, including their construction, marking, and permitted uses. This ensures that fixture wires are used safely in various electrical installations, particularly those involving lighting fixtures. Here is an overview of NEC Article 402:

402.1 Scope

This section covers the general requirements and construction specifications for fixture wires, including their use in luminaires and similar equipment.

402.2 Definitions

Defines key terms relevant to fixture wires to ensure clarity and consistency within the article.

402.3 Types and Markings

Specifies the types of fixture wires and the required markings. Fixture wires must be of a type listed in Table 402.3, and they must be marked with the type designation, voltage rating, and other relevant information.

402.5 Allowable Ampacities

Provides the allowable ampacities for fixture wires, ensuring they are used within safe operating limits. The table includes specific ampacity values based on wire size and insulation type.

402.6 Splices and Terminations

Requires fixture wires to be used in continuous lengths without splices or taps unless otherwise specified. If splicing is necessary, it must be done using approved methods to maintain safety and integrity.

402.7 Uses Permitted

Lists the specific environments and applications where fixture wires can be used:

1. For installation in luminaires and similar equipment where they are enclosed or protected.
2. For connecting luminaires to the branch-circuit conductors supplying the luminaires.

402.8 Uses Not Permitted

Specifies the environments and applications where fixture wires cannot be used, including as branch-circuit conductors unless permitted elsewhere in the NEC.

402.10 Construction Specifications

Details the construction requirements for various types of fixture wires, ensuring they are manufactured to provide the necessary flexibility, durability, and safety for their intended use.

402.11 Pull at Joints and Terminals

Requires that fixture wires be installed and supported in a manner that prevents undue mechanical strain on the conductors, joints, and terminals.

402.12 Overcurrent Protection

Specifies that overcurrent protection for fixture wires must comply with the requirements in Section 240.5.

402.14 Grounded Conductor Identification

Requires that fixture wires intended for use as grounded conductors be identified by one or more continuous white stripes on insulation other than green or by other means described in Section 400.22(A) through (E).

For further details and specific requirements, referring to the NEC Handbook and additional resources provided by the NFPA is highly recommended. You can find more information on the specifics of NEC Article 402 on websites like iBidElectric and The NEC Wiki.