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).

Register to view the full article

Register on EC&M and gain access to premium content, including this article and much more.

Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish