National Electrical Installation Standards

Standards as High as Your Own

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Tuesday, April 21, 2020

Question:

Hello, I am working in a lighting distribution on a new building, where I have 5 separate circuits with 10 lights per circuits. Can I run all the circuit using one conduit and using pull boxes to branch to different locations where the lights are.

Thanks,

Frank Hernandez

A

Answer:

Hi Frank, thanks for your question. The short answer is yes, you can install those lighting circuits in a single conduit. There are a few things to consider and apply to attain Code compliance. First, the installation would need to meet Section 300.17 and the specific conduit fill requirements in the XXX.22 section of the wiring method chosen for the installation. This section provides a reference to Table 1, Chapter 9 of the Code. Next, there are correction factors that would have to be applied based on the number of current-carrying conductors in the raceway. See Section 310.15. Where the number of current-carrying conductors exceeds three, a correction factor needs to be applied. Once those rules have been satisfied, be sure that the conductors are protected in accordance with their ampacities after the correction factors have been applied. See Section 240.4 and 240.6.

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