question for an electrician

[Steven Triggs]

I'm planning to add a 100 amp sub-panel to my existing 200 amp main panel. I'd like to run the feeder cable through the 2x4 walls, but I'm not sure if that is possible.

Basically, it would need to run horizontally through the wall for about 8' from the main panel, turn into a perpendicular exterior wall, run horizontally for about 3', go up and over and down to clear a window (cripple studs above solid header because of high ceiling), and then continue horizontally for another 2' before entering the sub-panel.

I believe the conducters will have to run in 1-1/4" conduit.

Is there a practical way to run this through the walls as I've described? If not, what would you suggest as an alternative route?

I've attached a simple drawing that I hope will help illustrate what I'm trying to do.

Thanks,
Steven

[Ryan Myers]

It would be easiest to use SEU enterance cable. You will need four-wire cable. 3 AWG for copper and 2 AWG for aluminum. This stuff is much faster and quicker then running conduit. It is not as pretty as conduit.

[Steven Triggs]

What size hole would need to be drilled through the studs for this? Would it not be too large of a hole for a load bearing 2x4 wall (to not violate building code)?

Also, can it make a 90 degree turn from one wall to another perpendicular wall? I didn't think it could be bent that tightly?

Thanks, and sorry for my ignorance. I've done a fair amount of electrical work from the panel down, but never before the panel, so I've never messed with wire this big.

[John Bush]

I had similar issues running lines to my shop and the simplest way was to attach flex to the top of the primary panel, perforate the drywall and run vertically to join a rigid pipe at the ceiling height for the horizontal run over a door and large window, then back down and into the wall with flex. I ultimately perfed the outside wall to a j-box and buried conduit to the detached shop, and all this attractive stuff is in the garage, so no aesthetic concerns. Definitely easier and to code as well. Good luck, John.

[Ryan Myers]

It's been awhile since I have installed that size cable, but I am thinking it was about 1 inch diameter. It can bend much tighter than conduit. I have installed it in 2x4 walls. Building codes vary greatly from place to place, so you may want to check with them on the max hole size you can drill through them. You would need about 1-3/8 hole for easy pulling.

This cable doesn't necessarily have to be installed in the studs as long ias it's not subject to physical damage.

[Randall Davis]

It would be easiest to use SEU enterance cable. You will need four-wire cable. 3 AWG for copper and 2 AWG for aluminum. This stuff is much faster and quicker then running conduit. It is not as pretty as conduit.


the 4 wire cable is SER

[Joe Chritz]

Copper is about 7/8" and it is a tight fit. Aluminum is a bit bigger.

Running separate wires inside conduit is most likely the cheapest route. If you opt of SER and run it inside 2x4's you will have to use metal nail plates for protection.

Do you have an attic where you can run it up, over and back down?

Joe

[Chris Friesen]

Building codes vary greatly from place to place, so you may want to check with them on the max hole size you can drill through them.

The OP may be able to double-up the studs to get a larger allowed hole.

[Steven Triggs]

You will need four-wire cable. 3 AWG for copper and 2 AWG for aluminum.

Ryan,
I went to home depot and got 2 feet 2-2-2-4 SER Aluminum cable. I got the small piece so I could "play" with it and see what it is like.

Anyway, this has 3 conductors of 2 AWG, and 1 ground conductor of 4 AWG. Is this the stuff you were talking about?

It is much smaller than I was imagining. I think I'll have no problem running it where I need to. I think I was picturing 2/0 as opposed to 2 AWG in my mind...