National Electrical Installation Standards

Standards as High as Your Own

Thursday, March 10, 2022


Greetings and thank you for this NEC Blog. I'm installing 125-volt receptacles in an operating room. They are supplied by an isolated power panel. These receptacles have a terminal for the grounded (neutral) conductor, yet the only wires in the outlet boxes are brown and orange.

Your opinion would be helpful.

Martin Gross



Hi Martin,

Thanks for the comments. Your question is interesting but the NEC does address it. This is a case where Chapter 5 (specifically Article 517) contains the requirement. Check Section 517.160(A)(5) which provides the conductor identification requirements. It should be noted that the brown and orange wires should also have at least one distinctive colored stripe. The last sentence in the section indicates that where isolated circuit conductors supply 125-volt, single-phase, 15- and 20-ampere receptacles, the striped orange conductor(s) shall be connected to the terminal(s) on the receptacles that are identified in accordance with 200.10(B) for connection to the grounded circuit conductor. These are listed systems and installation instructions would most likely address this. 

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