Article 348.6: Listing Requirements.
FMC and associated fittings shall be listed.
Article 348.20 (A): Size.
Minimum FMC less than metric designator 16 (trade size 1/2”) shall not be used unless permitted in 348.20 (A) (1) through 5 for the metric designator 12 (trade size 3/8”). (1) For enclosing the leads of motors as permitted in Article 430.145 (B). (2) In lengths not in excess of 1.8m (6 ft.) for any of the following uses:
- For utilization equipment.
- As part of a listed assembly.
- For Tap Connections to luminaries (lighting fixtures) as permitted in NEC Article 410.77.
Article 348.22: Number of Conductors.
The number of conductors shall not exceed that permitted by the percentage fill specified in Table 1, Chapter 9, or as permitted in Table 348.22 for the metric designator 12 (trade size 3/8”).
Article 410.137 (C): Equipment Not Integral with Luminaire (Fixture)
Wired Luminaire (Fixture) Sections. Wired luminaire (fixture) sections are paired, with a ballast(s) supplying a lamp or lamps in both. For interconnection between paired units, it shall be permissible to use metric designator 12 (trade size 3/8”) flexible metal conduit in lengths not exceeding 7.5 m (25 ft), in conformance with Article 348. Luminaire (fixture) wire operating at line voltage, supplying only the ballast(s) of one of the paired luminaires (fixtures), shall be permitted in the same raceway as the lamp supply wires of the paired luminaires (fixtures).
Wired luminaire sections are shipped in pairs and marked for use in pairs. Each individual unit includes lamps in odd-numbered quantities (one or three is most common), with the odd lamp in each luminaire supplied by a two-lamp ballast located in one luminaire of the pair. Two-lamp ballasts are more energy efficient than single-lamp or three-lamp ballasts.
Article 250.148: Continuity and Attachment of Equipment Grounding Conductors to Boxes
Where circuit conductors are spliced within a box, or terminated on equipment within, or supported by a box, any separate equipment grounding conductors associated with those circuit conductors shall be spliced or joined within the box or to the box, with devices suitable for the use. Connections depending solely on solder shall not be used. Splices shall be made in accordance with 110.14 (B), except that insulation shall not be required. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire (fixture) or other device fed from the box will not interfere with or interrupt the grounding continuity.”