Mark Gilligan
Member
My understanding
250.50(A) lists electrodes permitted for grounding. Assume that I selected and installed a rod electrode. Assume further that the building has a metal frame that was not relied upon to meet any of the code provisions. Further assume that the detailed methods under 250.52.(A)(2) were not complied with.
The code talks about permitted electrodes. Thus as long as I comply with one I need not comply with any of the others.
My assumption is that the metal frame need not be considered a grounding electrode and thus is not required to be bonded to bonded to the grounding electrode system. This is consistent with the plain meaning of the words in the code. In addition the metal frame is not part of the electrical system and is not a source of a ground fault nor is it used as a part of an effective ground-fault current path.
A Building inspector quotes the commentary to the code
"The Code does not specify that metal water pipe, structural metal frame, or concrete-encased-type electrodes have to be installed, only that where they have been installed as part of the building construction they are to be used as components of the grounding electrode system."
The building inspector claims that any metal frame in a building must be bonded even if it was not used as a part of the electrical system in the building. I suspect the inspector has ignored the word permitted and finds it irrelevant that the metal frame dos not comply with the detailed provisions.
The commentary is not code and while it may inform our understanding it cannot be the basis for a requirement not in the code.
If I am in error explain why. Also explain why my interpretation would create an unsafe condition.
If I am in error then I believe we will find many buildings not in compliance.
250.50(A) lists electrodes permitted for grounding. Assume that I selected and installed a rod electrode. Assume further that the building has a metal frame that was not relied upon to meet any of the code provisions. Further assume that the detailed methods under 250.52.(A)(2) were not complied with.
The code talks about permitted electrodes. Thus as long as I comply with one I need not comply with any of the others.
My assumption is that the metal frame need not be considered a grounding electrode and thus is not required to be bonded to bonded to the grounding electrode system. This is consistent with the plain meaning of the words in the code. In addition the metal frame is not part of the electrical system and is not a source of a ground fault nor is it used as a part of an effective ground-fault current path.
A Building inspector quotes the commentary to the code
"The Code does not specify that metal water pipe, structural metal frame, or concrete-encased-type electrodes have to be installed, only that where they have been installed as part of the building construction they are to be used as components of the grounding electrode system."
The building inspector claims that any metal frame in a building must be bonded even if it was not used as a part of the electrical system in the building. I suspect the inspector has ignored the word permitted and finds it irrelevant that the metal frame dos not comply with the detailed provisions.
The commentary is not code and while it may inform our understanding it cannot be the basis for a requirement not in the code.
If I am in error explain why. Also explain why my interpretation would create an unsafe condition.
If I am in error then I believe we will find many buildings not in compliance.