Code Q&A

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Sep 8, 2005 11:09 AM, By Mike Holt

Q. I’m working on an electric gate installation. Can I install control wiring in the same raceway with electrical power conductors?

A. Maybe. According to 725.26(B)(1), Class 1 circuits can be placed in the same cable, enclosure, or raceway with power-supply circuits, if the equipment powered is functionally associated with the Class 1 circuit (Figure 725-26B1 UN725-25). However, 725.55(A) states that Class 2 and Class 3 circuit conductors must not be placed in any enclosure, raceway, or cable with conductors of electric light and power. How do you know if you have a Class 1 or Class 2 circuit? Check with the manufacture and find out if the control circuit power supply is intended for Class 2 or Class 3 wiring.

Keep in mind that Exception 2 of 725.52(A) allows you to reclassify a Class 2 or Class 3 circuit into a Class 1 circuit if the Class 2 or Class 3 equipment markings required by 725.42 are eliminated and the entire circuit is installed in a Chapter 3 wiring method [725.55(D)(2)(b)] and 600V conductors are used. Note that Class 2 and Class 3 circuits reclassified and installed as Class 1 circuits are no longer Class 2 or Class 3, regardless of the continued connection to a Class 2 or Class 3 power source.

Got a question for Mike? E-mail him at mike@mikeholt.com.