I am a Master Electrician. For 18 months I did electrical inspections for the U.S. military in Iraq. Now for the past month and a half I have been doing electrical inspections in Afghanistan for the U.S. military. We have several British inspectors here also inspecting to the NEC 2008 code. A point of disagreement over the code has arisen and I was hoping that you could straighten this out for us as I consider you a foremost expert on the code.
Here is the current situation. We have circuits in structures that are not considered residential. These are containers for sleeping that are electrically fed from a transformer to a MDP (5 wire)where bonding occurs, to a SDP (5 wire) and then to a CDP (120v/208v 4 wire, 2 phase conductors, a neutral and an EGC)in the individual units. There is a 120v branch circuit run from the CDP panel through PVC conduit (distance of 4 feet but length does not really matter) to a light fixture that is made of plastic with absolutely no metal except the contact for the ungrounded conductor and a contact for the grounded conductor which is attached to the socket. This fixture is not required to be bonded and cannot be bonded as it is an all plastic non-conductive surface. But some of the inspectors contend that a EGC is required to be laid with the circuit conductors in the PVC conduit not attached to anything at the fixture end but attached to the ground bar in the panel. I said that was preposterous and asked them to cite what code article they were using for that requirement. They claimed 250.4 (A) (5). This states that there must be an effective ground fault current path anywhere on the system that a ground fault may occur. I told them you cannot have a ground fault in PVC conduit as it is not a conductive surface and that you could only have a short circuit. They then claimed that a short circuit and ground fault are the same thing. I said that is absolutely false and erroneous thinking and that is their error. I told them that a branch circuit requires a ground only if there is a requirement to bond something such as a conductive surface for the ground fault path (boxes, metal conduit, panels, motor frames, pipes, etc. or a device that requires it such as a receptacle or metal light fixture and such or where specifically required elsewhere in the code. I said NEC 2008 articles 250.4 (A) (2), 250.4 (A) (3), and 250.4 (A) (4) tell you what must be bonded and in Part V of article 250, Article 250.90 states that bonding shall be provided where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed.
So if you could, could you please state whether I am correct or they are and what code articles back that position. It would mean so much to the safety of the soldiers out here if we could be sure we are inspecting to the NEC correctly. I anxiously await your opinions.
PS. In article 200.3 there is a mistake in the code book. It states for any grounded conductor (should be ungrounded conductor) you require a corresponding grounded conductor. A little slip up I guess. Can we notify somebody about that?
Here is the current situation. We have circuits in structures that are not considered residential. These are containers for sleeping that are electrically fed from a transformer to a MDP (5 wire)where bonding occurs, to a SDP (5 wire) and then to a CDP (120v/208v 4 wire, 2 phase conductors, a neutral and an EGC)in the individual units. There is a 120v branch circuit run from the CDP panel through PVC conduit (distance of 4 feet but length does not really matter) to a light fixture that is made of plastic with absolutely no metal except the contact for the ungrounded conductor and a contact for the grounded conductor which is attached to the socket. This fixture is not required to be bonded and cannot be bonded as it is an all plastic non-conductive surface. But some of the inspectors contend that a EGC is required to be laid with the circuit conductors in the PVC conduit not attached to anything at the fixture end but attached to the ground bar in the panel. I said that was preposterous and asked them to cite what code article they were using for that requirement. They claimed 250.4 (A) (5). This states that there must be an effective ground fault current path anywhere on the system that a ground fault may occur. I told them you cannot have a ground fault in PVC conduit as it is not a conductive surface and that you could only have a short circuit. They then claimed that a short circuit and ground fault are the same thing. I said that is absolutely false and erroneous thinking and that is their error. I told them that a branch circuit requires a ground only if there is a requirement to bond something such as a conductive surface for the ground fault path (boxes, metal conduit, panels, motor frames, pipes, etc. or a device that requires it such as a receptacle or metal light fixture and such or where specifically required elsewhere in the code. I said NEC 2008 articles 250.4 (A) (2), 250.4 (A) (3), and 250.4 (A) (4) tell you what must be bonded and in Part V of article 250, Article 250.90 states that bonding shall be provided where necessary to ensure electrical continuity and the capacity to conduct safely any fault current likely to be imposed.
So if you could, could you please state whether I am correct or they are and what code articles back that position. It would mean so much to the safety of the soldiers out here if we could be sure we are inspecting to the NEC correctly. I anxiously await your opinions.
PS. In article 200.3 there is a mistake in the code book. It states for any grounded conductor (should be ungrounded conductor) you require a corresponding grounded conductor. A little slip up I guess. Can we notify somebody about that?
