Wanting to install a garage sub panel for 220v

[soob]

I want to get into woodworking, but my garage doesn't have the juice. Currently there's a 15A and a 20A outlet, both 110v. On different breakers obviously.

My goal is to add at least two 220vs. One would need to be able to handle a big tool: biggest would be a 5hp jointer/planer -- says 25 amp 220v. The other would for a mini split air conditioner for the garage (I can dream, right? 220V ~10amp). Also I'd have a dust collector (15A 110v) which would run at the same time. Then there's a 20A 110v compressor, but it probably wouldn't be run at the same time. The dust collector and the compressor could run from the existing outlets.

The house has the main breakers outside at the front, which has a 100amp breaker side-by-side with a 30A. Then there's the panel inside in the laundry room at the back. The panel at the back is (I believe) a 125amp, or at least it could be, but it doesn't seem to be configured like a main panel. The neutral and the ground aren't joined. Pictures are attached.

I have a vague idea of how to add a sub panel for the garage but my house isn't configured like I would have expected. Can I run it from the breaker box on the outside of the house--should I? Any special precautions?

Could the 125A box in the laundry room support the two 220s I'd need to add (with the existing load)?

 

[pattenp]

It looks like you have the room to stick in two 240V 2 pole breakers. If you just want to add only the two 240V circuits then just add one 30A for the joiner and a 20A for the AC. The panel you have is a main lug and has no disconnect so your neutral and ground are bonded outside at the meter panel where the 100/30 breakers are.

You can run a feeder from this panel and put in a sub-panel in the garage but it may be cheaper to run the two new 240V circuits if that's all you want. It just depends on how far your wire runs need to be.

 

[soob]

There's three free poles on each side. I guess I could move one so I could fit three 2-pole breakers, if I had to.

But that box is in the back, probably at the farthest point of the house from the garage where I'd want the 220v outlets. It's not that big of a deal, maybe 50' or so, not really a big problem. I'd probably want to daisy chain some 220v outlets but I guess that wouldn't be too much of a problem either.

So you think the (presumably 100A) box can handle that added draw? If it's got the range on a 40A and the dryer on a 30A, plus the fridge, when all those things run at once with the jointer and the garage a/c am I going to trip the "main" 100A breaker?

 

[pattenp]

With only having a 100A service it would be possible to trip the 100A breaker if you got the range, dryer, joiner, AC, and what other stuff you got going all at the same time.

 

[soob]

Well I took the cover off the outside panel (seemed like a bad idea last night in the rain) and there's no expandability whatsoever, at least not without replacing the panel. Unfortunately it was dark and the wires were hot so I wasn't able to size them up to see if I could possibly just slap a 125A breaker on there. I doubt it.

I may just go ahead and stick two 30A 220s in the garage off that "main" subpanel and see how that works.

 

[Charles (in GA)]

What does the 30 amp outside supply? An A/C unit that is located right there or nearby?

Its possible that the meter is 200 amp capable, look carefully at the data tag inside the face of it, its also possible the meter socket/disconnect panel is 200 amp capable, look at the data tag on the front of it or inside it (breaker side that you can open without disturbing the meter seal), and thirdly, you need to determine the size of the incoming power company wires and if they are capable of 200 amp (the POCO or an electrician can tell you this). If all three things tell us the incoming wires, meter socket/can and the meter itself, are all 200 amp capable, you could remove the 30 amp and install a larger breaker and the appropriate cable to supply a garage sub panel, relieving the 100 amp main of those loads. In some panels that 30 amp would be fed thru the 100 amp, but I'm willing to bet the two are both supplied off the bars coming from the meter.

Its all worth looking into.

Charles