Is an equipment grounding conductor required with EMT or metallic conduit?
(1/8/2003) A: EMT is acceptable as the required equipment grounding conductor, as is rigid metallic conduit or IMC. SECTION 250-122(f) Q: 11 sets of 500 KCMIL conductors (3 phase, 4 wire) run in separate conduits, fed at 120/208V by a 4000 Amp fused service switch. What is the minimum size of the equipment grounding conductor required in each conduit? (3/12/2003) A: If installed in nonmetallic conduit, a 500 KCMIL conductor is required in each conduit, as per Article 250-122(f). If installed in metal raceway, no additional equipment ground is required. However, if an equipment ground is installed, the same rules for nonmetallic raceway would apply. SECTION 250-30 Q: Is it allowed to obtain the neutral wire for a 208V, 3 phase apartment riser from a grounded step down transformer? All 4 wires will run in the same conduit, from the transformer to the apartment panel. (4/9/2003) A: The derived neutral ground at the secondary of the 480-208/120V transformer may be used as the neutral wire.
