I need an electrician to come work on a couple items and was considering asking for him to put in a pair of 20amp 10 gauge solid wire lines for my BHK Signature 300 mono blocks. The first problem I know of is my breaker panel being full currently. I don’t have a single open spot for a new breaker. I did see they make breakers that can somehow manage multiple lines, but I don’t underhand how the works and if it would be an option to gain me more space or if I would need to bite the bullet and have a new larger panel made. Does anyone have any experience adding lines to a panel that is already out of open slots? What is the best way for me to do this and could you give me a ballpark on cost is possible. Not holding anything to their estimates, just like to have an idea first before I waste an profesionals time.
Yes, I have faced this issue. If you are lucky, you may have two panels, the one you deal with normally with all the breakers you typically deal with to reset or temporally disconnect power and a main panel, almost always outside directly attached to the meter. That was my case and I had my electrician run a 50 amp line from the main panel to a second sub panel wherein I have several 20 amp breakers with 12 gauge lines to PS Audio outlets serving my HiFi system. That was less than $2K. Now for an unrelated need, I later needed to add an additional sub panel but was now at your situation with no room for more breakers (except in that new sub panel except it was on the wrong side of the house). I bit the bullet and had the main panel replaced, $8K ouch. Now in your case, there is an option if you don’t have a main panel from which to run another sub panel or that main panel is also full. There are ganged breakers that can replace singles. Perfectly code. And rather simple for an electrician: remove to adjacent single breakers, and installed the two lines on a new double leaving an empty slot for you new circuit. Now how you get that new 20 amp line from you panel to where it needs to go is another issue. I had the line from my main panel to the new sub panel run outside the house and then the line to the new outlets comes into the house through the exterior wall. Might seem unsightly put you already have lots of wires outside you house: main electric feeding down to your meter, cable, old phone line. And no matter where its runs, I promise after six months you won’t notice it. And, by the way, run two new 20 amp lines when you do it, only a little more than the cost of the copper as they will need to run a new conduit if the lines are outside you house. And also, I (meaning if it was me) would not double breaker the two new 20 amp lines but rather double breaker four existing lines and use two new single 20 amp breakers. You can terminate the two new lines in a new double box where each feeds its own outlet. But if you do, label the outlet to clearly indicate that it is fed by TWO separate lines, even an experienced electrician would anticipate needing to trip only one breaker to work on an outlet box.
if you have what I would call a normal wide breaker, most panels at the lower portion will support 1/2 width ones. my panel is chalk full of them.
Buy the replacement one half width, and new 20 half width that fits your panel and then put them in. I do it myself all the time. its easier than you think. Adding a sub panel is usually next option. Getting a new panel is a last resort IMO.
EDIT: some like my GE Panel the half breakers come as a 2 in one breaker. So replace a fat 20 with a double skinny 20. easy.
Like these guys here are saying a dedicated sub panel is best, but you are full. To do that you would need to add A sub panel and free up a bunch of space and then use some of that space for a second sub panel. put a 40amp sub panel in and move 4 of the smaller less in use breakers to that, then the left over space do the subpanel for the music room… again not cheap, but probably cheaper than replacing the whole panel.
Do what Jim (JKW) did. If you can do it, it’s the best way to go. Have the electrician run copper from that main breaker to the new subpanel. Use 10AWG THHN then from the new subpanel breakers to the dedicated outlets. Pick the 120VAC side that has the least nasty stuff on it and use that one. I have a 100A breaker in my main box that drives a 2AWG copper line to a dedicated subpanel just outside my listening room. Six separate 20A breakers to dedicated outlets, twisted THHN 10AWG copper. One ground point in the subpanel. Do not use either ROMEX, or metal conduit, or metal junction boxes. I’ve tried all that and more. IME the way I have it now is best. Even the brand of subpanel box and circuit breakers matter, but that’s a deeper rabbit hole. 