Mike Dolt Enterprises
Mike Dolt Enterprises
User: madchad, Location: Columbia, MD USA
Asked on: Friday, April 1, 2011 at 11:40 am EDT
Answered on: Tuesday, May 14, 2024 at 3:36 am EDT
Question: I have encountered a 200a panel feeder installed on the side of a building in EMT with compression fittings. The circuit originates in the MDP on a balcony and is continous until it gets to the point where it enters the building. At that point, there is a short section of EMT penetrating the exterior wall (which goes to the panel) with a weatherhead mounted on the end of the EMT outside. So the coductors are in free air for about 3'. They are utilizing the EMT as a GEC. They did install a ground wire (cant see what size or method they used) connecting the two sections of raceway but i am not sure this is legal. The EMT consists of 3 hots and a neutral, no ground. I cant find anything that states this is illegal. I thought i had it with 310.10....NOT. Is this a legal install?
The installation described is not compliant with the National Electrical Code (NEC).
Grounding Considerations
NEC 250.118(8) prohibits using raceways as grounding electrodes. NEC 250.118(10) requires metallic raceways to be grounded.
EMT as a Raceway
NEC 358.12(1) requires EMT to be installed in continuous lengths without splice or couplings. The installation described violates this requirement because the EMT is not continuous through the exterior wall.
Free Air Conductors
NEC 300.3(C) prohibits the installation of conductors in free air unless the conductors are specifically listed for such use. The conductors described are not listed for free air installation.
Conclusion
The installation described is
not legal according to the NEC. The following steps should be taken to correct the deficiencies: Install a grounding electrode system and connect it to the EMT raceway. Remove the discontinuity in the EMT raceway by using a continuous length of EMT through the exterior wall.* Install conductors that are listed for free air installation. Flag for review