Reply by Lazyman

Well, I decided to look into my panel a bit more. What would be nice, is if I could install a sub-panel just to the left of the main panel. Basically on the other side of the stud. That would be the shortest distance I could imagine, and it would still be in a convenient location in our garage. There are knockouts on the sides of the main panel, and they butt right up to the stud. I m sure there is some sort of regulation for running cable through a stud, but I m just wondering if I m way off base?

You can see the unused 50a that I m talking about. Would that breaker be suitable to power the sub-panel?

It sound like I may as well install a flush mount sub panel. Can I still bring the cable to the surface and run it externally through conduit?

Thanks to everyone who has commented so far!

- derrick3636

I am not an electrician (so consult one) but you should be able to use the 50a breaker you’ve got. Based upon Mike’s chart above, you’ll need a minimum of 6 ga wire to the sub-panel as long as you keep it under 20 feet or so. I can’t imagine that you will ever need more than 50 amps based upon your list of tools so 100a would be way overkill in my opinion. You would have to run 3 of them at the same time to get close to 50. As I understand it (and I am sure that someone will correct me if I am wrong), you can have 2 120v circuits off the sub-panel and have up to 50 amps on each (assuming appropriate gauge wire) as long as you have the 2 120v breakers on separate sides of the panel. 240v machines will pull the same amps from both sides so theoretically, you should be able to run your 5HP 15amp planer plus another 15amp 240V dust collector and still have up to another 20 amps to spare on each of 2 separate 120v circuits.

You may be able (allowed?) to drill through the stud up against the side of the main panel, but that may not be the easiest way to do it. It might be easier to go out the top or bottom of the main box as it appears they did with all of the other wires and then over to the top of the sub panel. Personally, I would not mount the sub-panel on the same stud as the main panel, even if it is allowed by code. A little extra space is always a good thing when you are trying to route heavy gauge wire. I would rather patch some extra holes in the wallboard than work in cramped space.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.