Our (New Jersey) house is a split-level, and the main load-center for the house is in the garage. We are installing a new sub-panel in the (1/2 below-grade) basement on the opposite side of the house. To avoid messing up the interior, we are running service cable (SER 3-3-3-5) outside, under the eaves, along the exterior of the house, and then down to the basement, to reach the new panel. Probably because of stupidity, the new sub-panel is not on the basement exterior wall through which the cable will pass into the basement, but several feet away.


Does anyone have suggestions how pass the cable through the wall(s), and to protect the cable and guard the basement (and garage) against humidity/elements ?

I asked my town inspector what he would like to see: he said 'make a hole,' which I can do, and add some electrician's sealant putty to insulate. I suppose this is pretty much in line with Getting Ethernet Cable Through Exterior Wall but....


The (1/2) below-grade basement, 7-foot high, exterior walls consist of foundation blocks. These walls are crowned with 2 horizontal 2 X 4's (the 'bottom plates' - I am sure the incorrect term), 4'' sides face down, upon which rest outward-facing 8 X 2's and the cross-beams for the floor above. I was planning on passing the cable through the 8 X 2 (i.e., to have the cable high as possible) - the inspector is OK with this.

The garage wall is the 'usual' above-ground wall, made with 2 X 4 s, with sheet-rock on the interior and shingles on the outside.

Thank you for your time,


  • If this is your service feed it will require conduit when entering the home until the main panel/ breaker. – Ed Beal Oct 8 '19 at 20:40
  • No, it is not a service feed: I am running cable between a subpanel and the main panel. [I've submitted plans to the town, and they have been approved.] - Or am I misunderstanding your comment? – peter a g Oct 8 '19 at 20:44
  • What are the exterior finishes? Wood/vinyl/metal siding, brick, etc? The penetration will be much larger than that for an Ethernet cable, so I'd be more interested in sealing the conduit to the water barrier layer which should be hiding behind the exterior cladding. Regarding the route: you might consider an exterior route from the garage into the house attic, then an interior route from attic to basement. The attic-to-basement is especially easy if you route through the rear or side wall of a closet where access holes at the top and bottom of wall are easy to repair/hide. – Greg Hill Oct 8 '19 at 23:04
  • Consider 1-1-1-3 Aluminum. Many people are spooked by aluminum unnecessarily; it's actually ideal for this type of heavy feeder, and 1/3 the price. In fact, the lugs you'll be attaching to are probably aluminum. – Harper - Reinstate Monica Oct 9 '19 at 0:23
  • @GregHill Thanks - the exterior consists of wooden shingles. And, unfortunately, the interior route isn't available, without making a marriage-imperiling mess. I wasn't sure about conduit either - as you might gather from my description, the town inspector hadn't thought it necessary. – peter a g Oct 9 '19 at 0:31

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