I'm planning on installing a 100amp sub panel in the garage. The garage is right around the corner from the main load center in the basement, but part for that path goes through the stairway from the garage into the basement. I think it might be required or at least a good idea to have the wire protected in a conduit for that part of the run.

I am planning on using 1/0-1/0-1/0-2 Al SER wire for the run.

Should it be in a conduit for some or all of the run? What size if needed?

The total run should be about 30 feet with going around bends.

Photo of the basement from the main load center looking to the doorway to the garage. Basement from main load center to doorway leading to garage From the garage doorway looking at the stairs up and the back of the garage wall. From doorway to garage wall


2 Answers 2


No, conduit is not required

Wires equal to or greater than two #6 AWG or three #8 AWG can in fact be secured to the bottom of the floor joists per Code.

334.15 Exposed Work (C) In Unfinished Basements and Crawl Spaces. Where cable is run at angles with joists in unfinished basements and crawl spaces, it shall be permissible to secure cables not smaller than two #6 AWG or three #8 AWG conductors directly to the lower edges of the joists.

Technically SE cable ran indoors is treated as NM cable....

338.10 Uses Permitted (B) Branch Circuits or Feeders. (4) Installation Methods for Branch Circuits and Feeders. (a) Interior Installations. In addition to the provisions of this article, Type SE service-entrance cable used for interior wiring shall comply with the installation requirements of Part II of Article 334, excluding 334.80

I'd recommend metallic flex though if a conduit is to be used.


SER is fine. Looks like steel joist. You could sleeve conduit to block wall,may help. You do not have to drill joist and if you want, run a running board.To mount cable or conduit. And have it for future use,under the house.

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