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Thursday, June 1, 2017
Question:
Pertaining to 240.21(C) ...... "without overcurrent protection at the secondary, as specified in 240.21(C)(1) through (C)(6)....". Question, the way I read this the installation need only meet one of the six parts to comply. [ the installation does not meet (C)(1) but does meet (C)(2), so I am still legal to use only primary overcurrent protection ] Correct ?
Edward Ryding
A
Answer:
Hey Edward thanks for your question. Yes, maybe somewhat. Section 240.21 applies to the location of conductor overcurrent protective devices. If you comply with all of 240.21(C)(2) for example you do not need to meet 240.21(C)(1) . But notice that overcurrent protection at the end of the secondary conductors is included in 240.21(C)(2)(1)(b) under the conditions stated. And you need to provide transformer overcurrent protection as stated in 450.3, which has options for primary only and primary and secondary protection.