Section 348.20(A) of the 2011 NEC tells us that flexible metal conduit (FMC) smaller than ½ in. is permitted only for the following five applications.

1) For enclosing motor leads.

2) Maximum of 6 ft lengths for wiring utilization equipment, listed assemblies or luminaire tap connections.

3) Manufactured wiring systems

(4) Hoistway wiring, and

5) Listed assemblies for connecting luminaire sections.

The 3/8 in. FMC in this photo is much longer than 6 ft. In fact, the FMC continues for approximately 20 ft in this installation. It was used to wire a photocell mounted on the outside corner of the building. If there is no equipment ground wire installed inside the FMC then it is also creates a violation of 250.118(5)(c), which places a 6 ft limit on using the FMC as an equipment grounding conductor.

Also, since the FMC is tie-wrapped to the electrical metallic tubing (EMT), there is yet another violation. Section 300.11(B) generally does not permit ½ in. EMT to be used as a support of other raceways.

Lastly, section 348.6 requires FMC to be listed. The FMC used for this installation is not listed.