National Electrical Installation Standards

Standards as High as Your Own

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Tuesday, September 17, 2019

Question:

What is the difference between Article 376.23(A) and 376.23(B)?  What is an example or application of 376.23(A)?

Thank you for this forum, Paul
A

Answer:

Hey Paul thanks for your question and you are welcome. Metal wireways are raceways as defined in 376.2 and are often used for multiple circuit conductor installations that are many feet in length. The title of 376.23 indicates the rule is for insulated conductors so it is about avoiding damaging conductor insulations during their installation.

If insulated conductors are pulled into the ends of metal wireways then the rules in 376.22 are used to size the metal wireway. If the conductors are pulled in at other than the ends, or if the wireway has an elbow that changes the wireway direction more than 30 degrees, the "width" of the wireway at that point must be at least that of Table 312.6(A) as stated in 376.23(A). For example, this applies if a cable entry or raceway is connected to the side of the metal wireway.

It is becoming more common to use short sections of metal wireways in place of a pull box. The dimensions of metal wireways used that way need to be at least that of 314.28(A) - typically 6 times (for angle pulls) or 8 times (for straight pulls) the raceway size.

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