When the NEC talks about “wireway,” it is referring to a specific type of raceway. Wireways come in two types:
- Metal. These are sheet metal troughs with hinged or removable covers. They house and protect wires and cables, which are laid in the wireway after it is assembled as a complete system.
- Nonmetallic. These are the same as metal ones except they aren’t metal. They are, however, made from a flame-retardant material.
Obviously, the nonmetallic wireway can’t be used as an equipment grounding conductor (EGC). But can a metal wireway be used as an EGC? Section 250.118 lists types of EGCs. There 14 types listed. Wireway isn’t among them. But would number thirteen, “Other electrically continuous metal raceways and listed auxiliary gutters” include these? We can look more closely a these by turning to Article 376 (the nonmetallic ones are covered by Art. 378).
We don’t see anything under “Uses Permitted” [Sec. 376.10] or “Uses Not Permitted” [Sec. 376.12]. However, we find under “Grounding” [Sec. 376.60] you can use listed metal wireway an EGC. It does, in fact, make an excellent EGC because if its cross-sectional area. However, you should make any bonding connections to the body of the wireway not to any hinged or removable covers.
Note also, it must be a listed wireway. Custom-fabricated sheet metal ones may actually function just fine as EGCs, but they are not listed for this purpose and so cannot be used as EGCs.
