Power for the shop

Mar 15, 2009 34 Replies

I've been looking into getting a new table saw, and since I only have



110v in my shop, I've limited my choices to contractor and hybrid saws. I started wondering about the possibility of pulling 220v into the shop and did some poking around in my breaker box. My circuit box has the old style 'pushmatic' breakers and is completely full, so adding a new 220v breaker really isn't an option. So, now I'm wondering about tying into an existing 220v circuit.

There are two 220v circuits: a 30 amp for the air conditioner, and a



50 amp for the dryer. I don't think that using the air conditioner circuit would be a good idea, especially in the summer. But, the dryer circuit looks like a good possibility - assuming that we don't run the dryer at the same time as the table saw. I was really surprised to find that the dryer circuit was 50 amps - how much power does a dryer really pull?

So the question is, is it OK to branch off of the dryer circuit and run it out to the shop? Would it be OK to run a table saw on a 50 amp



220v circuit?

Update: I went and looked at the label on the back of the dryer - it says that it should be hooked up to a maximum 30 amp circuit. Maybe I should look into installing a small sub-panel in the garage, then run a 20 amp circuit for the table saw, and a 30 amp circuit for the dryer.

If your main box is maxed out, that's probably a good idea, anyway. While you're at it, you could upgrade the shop's electric a little. Who knows when you'll want another 220 tool? Maybe add some GFCI breakers to the new panel for the shop circuits.

Most likely your building codes will dictate that the dryer has to be on its own "dedicated" circuit.

"Mike" wrote

Probably not "branch off" ... the dyer is most likely on a dedicated circuit, depending upon the requirements of your city code/NEC, but there is nothing to stop you from unplugging the dryer and plugging in the saw, providing you have the right plug for the saw.

Absolutely... as long as the motor is wired for 220/240v operation.

The 50A circuit breaker is there for the sole protection of the insulation on the wiring of the branch circuit, and not for the saw's protection. The saw should have it's own internal thermal protection.

Ok or not according to code, I did. I tapped into the dryer circuit at the outlet and added a 220 outlet about 18" over. I can run my cabinet saw, stationary 15" planer or my 4.5hp Laguna band saw while the dryer is running. I did not intend to run both at the same time but my wife entered into the equation one day and inadvertently proved that both will run on the same circuit.

Be certain to run the proper gauge wire. You can run your 220 volt saw on a

200 amp circuit if you want. A decent saw should have it's won over load protection built in. The circuit breaker regardless of rating is strictly intended to protect the wiring in your house.

Knock, knock, knock... "THIS IS THE OUTLET POLICE, OPEN UP." ;-)

That's not quite how it works. Where there are laws governing such things, the buyer will have the house inspected to be sure it meets code. It might escape notice; it might not. Or, in the event of a claim, the insurance company might find that the non-compliant condition was causative. You have to ask yourself if it's a good law. If it is, you should consider the wisdom of circumventing it for whatever your reasons. If it isn't, you should work toward having it revoked or revised so it becomes reasonable.

What buyer? Do you have people inspecting your house all the time in case they want to buy? Seems to me, if you are going to sell you'd probably start dismantling the shop anyway and can remove wiring easily.

As for the insurance claim, something has to go wrong first. Then it has to be related.

Put a sign over the outlets: "Dryer 1" and "Dryer 2."

Any wiring I do in my house is a vast improvement on the original, which in some cases, leads me to believe a previous owner was trying to invoke an insurance claim or get rid of a divorced spouse.

My work will meet or exceed code, in any case, especially some of the goofy stuff they require in TN.

Run a disconnect. It is a separate switched fuse or breaker box, connected directly to the main buss. From there you can run an "expansion panel"

Or remove one of the 220 brekers and replace it with the largest you can get and wire the "expansion panel" to that breaker, installing a breaker for the original 220 volt load in that panel.

You don't say. We talk about honesty here, and pride ourselves in the little things, some of them largely inconsequential. Is it a good law, to require a building permit, licensed electricians, and followup inspection? Who gets to decide? Everyone for themselves?

Were we talking about keeping the bushes trimmed, or were we talking about the electrical work in the home?

I agree that requiring an inspection is a good law. The permit is required as the fee pays for the inspection. In my area a licensed electrician is not required for a single residence when the homeowner does the work.

The building trades are available, why not ask an electrician? Probably, if you dislike the 'old style' breakers, a new breaker box (or even an upgraded service) would be an option to consider.

It doesn't take a full work day to replace an existing box, just some prudence and skills, and a licensed electrician can get your situation sorted relatively easily. Building permit required, usually.

Yeah I know, but I "think" a home owner can do what he wants, although he will probably have to make it right if he plans on selling the house. If I move I simply plan to remove the extra outlet.

From what I understand, if the wiring was the cause and you personally did the wiring the insurance co. still has to pay up. This would not be the case however if they found that you intentionally make the wiring modification to burn your house down.

Similar to car insurance, if you run a red light cause a wreck and get ticketed they still repair your car.

IIRC that is how my agent explained it to me when I told him that I added an outlet during a reevaluation of my coverage. They are only concerned about major wiring changes to the breaker box. They want to insure that there are no unprotected circuits.

Pushmatic breakers? Probably from the 50's or 60's. FWIW, my electrician friend who likes to go overboard on everything says they are a fire waiting to happen. I'd go with a new, upgraded breaker panel with a sub-panel in the shop. Then you can go out and buy some BIG tools!

Mike wrote:

Back in Nov. I did just that. It cost me about $375 for a new panel, breakers, plus a 12ft run for my 220v space heater. It took about half a day. The electrician was happy to get the work and I was happy to have someone else do it. Now I've got two additional

110 runs and room for 5 (or 2 plus 1) more in my box -- just in case I want to expand and/or upgrade.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required