Protecting Ungrounded Conductors N-sky/iStock/Thinkstock

Protecting Ungrounded Conductors

There’s a pretty big twist if you’re providing protection to motor circuits.

A fuse or the overcurrent trip unit of a circuit breaker must be connected in series with each ungrounded conductor [NEC Sec. 240.15(A)]. Also, the breaker must open all ungrounded conductors of the circuit both manually and automatically [240.15(B)]. There’s a pretty big twist to this, however, if you’re providing protection to motor circuits (see Parts III, IV, V, and XI of Art. 430).

For the ungrounded conductors of a:

1) Multiwire

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