I need to run SER cable from my main panel to a subpanel in an attached garage. The run will be perpendicular to the first floor joists. Can I run the SER cable without conduit in the 1-1/2 inch gap created by the sill plate between the top of the basement wall and the bottom of the first floor joists, instead of drilling a hole through every joist? I am also assuming it would have to be fastened to the sill plate some how. See picture: Sill Plate Gap

  • SER never requires conduit. In some installations it requires physical protection against damage. You can use any tough material for that, see 300.4. Commented Dec 28, 2022 at 3:24
  • to my eye the plate constitutes a running board, and the recess is also protection.
    – Jasen
    Commented Dec 28, 2022 at 12:05

1 Answer 1


That could be an improper exposed location.

You are allowed to run wire through the joists and thus away from the face of the joist, but to run it against the front face or against the plate or concrete wall you need to run it in conduit if the wire is 6 AWG or smaller.

This has to do with the risk of physical damage.

In exposed work, except as provided in 300.11(B), cable shall be installed as specified in 334.15(A) through (C).

(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. Smaller cables shall be run either through bored holes in joists or on running boards. Nonmetallic-sheathed cable installed on the wall of an unfinished basement shall be permitted to be installed in a listed conduit or tubing or shall be protected in accordance with 300.4.

You could install a running board against the joists (1x3 lumber or strips of plywood) and nail smaller wire to it.

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