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Thursday, July 27, 2017

Question:

Table 250.122 requires that a copper equipment grounding conductor for a 5000A feeder must be 700 kcmil (assuming no other rules require increase).  Is it permissible to use 2 – 350 kcmil conductors instead?  If it is acceptable, what rule supports this?

John Duggan

A

Answer:

Hey John thanks for your questions, we will address them separately so watch for the second one. The words "phase, polarity, neutral, or grounded circuit" are used in 310.10(H) to describe the types of conductors that are allowed to be paralleled. Equipment grounding conductors that are paralleled must be sized using 20.122 with no specific mention of using smaller equipment grounding conductors in parallel. Both 310.10(H)(5) and 250.122(A) allow sectioned equipment grounding conductors within multiconductor cables. Now would be a good time to submit a Public Input to 250.122(F) with substantiation why smaller equipment grounding conductors connected in parallel should be allowed. You have until September 8 of this year.

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