Electrical and lighting in unfinished basement ?


Old 09-03-16, 12:12 PM
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Electrical and lighting in unfinished basement ?

I have a plan to wire new lighting in my basement. However I would need to protect the cable running down the unfinished cinder block wall.

1. My #1 choice is to just switch from NM to THHN whenever i need to do this. It will total about two conversions for two light switches. I would just use the junction box I am putting the switched outlet in to make the conversion.

2. Another choice though I am not sure if it is up to code is to somehow run the NM cable in the conduit only when going down the wall. I am getting mixed answers on this though.

What do you guys suggest I do?

On an unrelated note I plan to run a 20am circuit for my workshop and would use THHN from NM for that. I worry about stuff hitting exposed cables and would like to make sure the area is safe. Just not sure the best route to take for the lighting.
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Old 09-03-16, 12:36 PM
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NM is non metallic cable like Romex. THHN is single conductor wiring and needs to be installed in conduit.

You can run NM-b cable down a block wall. Fasten a piece of wood to the block and staple the cable to the wood.

Since this is your shop and the wiring could be damaged..... you could sleeve the NM-b cable down the wall in conduit. As a rule you wouldn't want to wire the entire place with NM cable in conduit.
A short sleeve in conduit for protection is approved.

I would run two circuits for the shop. A 15A circuit for the lighting only and a 20A circuit for the receptacles. You don't want a defective/shorted tool causing the lights to go out.
Old 09-03-16, 12:45 PM
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I usually run a short length of pvc conduit from plastic box up to the joist space and run the NM in that down to the box. If you use metal conduit, you need to put a bushing or fitting on the top so it doesn't cut the NM. Most common solution is just to install a box fitting on the end of the conduit (but no box). The box fitting has a rounded edge that won't cut the cable.
Old 09-03-16, 05:42 PM
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I think I will go this route with the PVC conduit. Any rules on the diameter I should use?
Old 09-03-16, 05:54 PM
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No specific rules but a suggestion would be to use " for more than one #12 cable. The scientific way would be to determine the area occupied by the outer sheath of the cable and try to keep total filled area at 40% or less than the area of the cable or cables.
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