National Electrical Installation Standards

Standards as High as Your Own

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Friday, November 10, 2017

Question:

We are adding a 70v speaker system to an outdoor covered pool in Maryland.  Using JBL control 28 speakers with the weather resistant modifiers. We could not seem to find the NEC code related to conduit requirements for the 70v speaker wire. Metal, plastic or none?  The plan is to run cable from the clubhouse mixer and A/v room out to the speakers at the pool.

Any advice, Robert Stern

A

Answer:

Hey Robert thanks for your question. The wiring method could be a Class 3 Cable as stated in 725. 133 depending on the power supply, but if installed in corrosive environments the wiring methods must be listed and identified for that as stated in 680.14.  The instructions for the equipment might also have specific details that must be followed as stated in 110.3(B). Sections 640.9 and 640.10 have some additional references.

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