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Friday, November 4, 2016
Question:
A substation transformer that was originally an ungrounded transformer was replaced in 2007 with a new transformer that had a wye secondary that was grounded. Making the system a grounded system. Is everything that is connected to the substation now required to be grounded and follow article 250 for grounded and bonding? Or just new installations after the new transformer?
Brad Placzek
A
Answer:
Hey Brad thanks for your question. The decision is up to the AHJ but if you don't ensure that 250.4 is complied with, the existing installation can result in an unsafe condition. If the original installation was properly installed to comply with 250.4(B) it might not be that difficult to make it now comply with 250.4(A).