On one hand:
344.6 Listing Requirements. RMC, factory elbows and couplings, and associated fittings shall be listed.
352.6 Listing Requirements. RNC, factory elbows, and associated fittings shall be listed.
358.6 Listing Requirements. EMT, factory elbows, and associated fittings shall be listed.
342.6 Listing Requirements. IMC, factory elbows and couplings, and associated fittings shall be listed.
I see that every conduit type is required to be listed. So, a code compliant installation will not include using "homemade" conduit or using the railing on a guard wall or the top-piping on a fence for conduit.
On the other hand:
376.10 Uses Permitted. The use of metal wireways shall be permitted in the following:
(1) For exposed work
(2) In concealed spaces as permitted in 376.10(4)
(3) In hazardous (classified) locations as permitted by 501.4(B) for Class I, Division 2 locations; 502.4(B) for Class II, Division 2 locations; and 504.20 for intrinsically safe wiring. Where installed in wet locations, wireways shall be listed for the purpose.
(4) As extensions to pass transversely through walls if the length passing through the wall is unbroken. Access to the conductors shall be maintained on both sides of the wall.
I see that a "homemade" metal wireway is permitted in dry locations if it meets the construction requirements of:
376.120 Marking. Metal wireways shall be marked so that their manufacturer’s name or trademark will be visible after installation.
What kind of requirement is this? I stamp my tin-foil wireway with my logo: "cheapo-electrical supplies", and I have a code compliant installation.
Pull boxes are a different story:
(B) Thickness of Metal. Sheet steel boxes not over 1650 cm3 (100 in.3) in size shall be made from steel not less than 1.59 mm (0.0625 in.) thick. The wall of a malleable
iron box or conduit body and a die-cast or
permanent-mold cast aluminum, brass, bronze, or zinc box or conduit body shall not be less than 2.38 mm (3⁄32 in.)
thick. Other cast metal boxes or conduit bodies shall have a wall thickness not less than 3.17 mm (1⁄8 in.).
I have a construction standard for boxes, and none for wireways. I have to use listed conduit and fittings, but I can manufacture my own wireways and boxes.
