Just got myself a new table saw (13 amps- Delta 725T2). I'm thinking of rewiring the saw to 240V. Also need a separate line for dust collection 20 amp should suffice. And another one for another tools.

In the future really want to dive into TIG welding and acquire a band saw. planer and jointer.

Please advise on the breakers to put in. The main panel is just behind the garage wall. Was thinking about using EMT as an option for more professional look.

I am pretty sure that I will not use two high amp tools at a time.

Really looking for advice from electricians on the breakers amperage that I need to install on the three lines.

  1. High amps tools;
  2. dust collection;
  3. regular tools, charging stations for hand tools.

I have a 200 amp panel (505 amps in breakers already in it)

[Panel description1

  • Need help with: - Amperage for three circuits. -Size of EMT conduit to use. - Wire size for each line (really want to stick to the code).
    – MrBaku
    Commented Dec 4, 2020 at 5:12
  • 20 AMP for dust collection??? Wow that thing must work great! Anyway you have plenty of space so the hardest thing is running the lines. It looks like you will want a 30 and 20x2. There are a lot of good electricians on here that will give you a good answer. If your panel is further away I would run them all at once. (so you really need to add where this panel is and how you can get to it from garage)
    – DMoore
    Commented Dec 4, 2020 at 5:53
  • I have that table saw, and 'rewiring' it for 240v was a simple as opening a cover on the motor and flicking a switch, then swapped the plug.
    – brhans
    Commented Dec 4, 2020 at 7:09
  • While I fully understand your question, and it is good to plan ahead, this is far to broad to be answered within our standard format. Since we (and you) don't know what future items you'll have, it's very difficult to advise you on what breakers to install and what circuits to run.
    – FreeMan
    Commented Dec 4, 2020 at 12:37
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    @ThreePhaseEel Thank you! 1200 sq.ft and the two car garage with a single 120V outlet (behind the garage wall is boiler room with the panel, very easy to access... was wondering what wire gauge I need and how to properly drop it in the garage up-to-code...that is why I've mentioned EMT conduit.... !Panel Name. !Panel Items.
    – MrBaku
    Commented Dec 4, 2020 at 14:31

1 Answer 1


You will be a LOT happier later if you just decide from day 1 to never buy a shop tool that CANNOT be rewired to run off 240. A 13 amp 120v saw uses 7.5 amps at 240 and the motor runs a lot cooler without all that extra current. This goes for your dust collector as well. Also by standardizing on 240 you can buy used commercial tools that are setup for 240 and they will be of better quality and probably cheaper than 120v residential home shop stuff.

With that said you might consider that you will want to use motor start switches (Allen Bradley, Furnas or equivalent) on any motors that do not have thermal limiting on the motor. These are essentially "breakers" so you don't really need to put a 1 for 1 breaker for each tool.

Yes you can go to the trouble of running EMT all over but I would not do that. Instead I would replace any of the "crummy" power cords on your tools with the NEMA rubber covered cable that is standard for use in shops. You can use the #14 guage stuff for your 7amp saw which is not that expensive. Then build a power distribution system consisting of a series of 240v electrical outlets in steel boxes that are on the ends of NEMA cables going into a central box, kind of like an octopus. Put an assortment of lengths of cables on the central box. Then a heavy 10 guage rubber covered cable from that to a single 30 amp outlet going to a 240v breaker. The reason I would advise doing it this way is that you are NOT going to know the optimal layout of where you want to put your shop tools in the space you have until you buy them and use them for a while. It is cheaper to run all this off a power distribution built from cables which can easily be moved around the shop as you decide to reorganize your shop tool layout. Also as an extra trick you can run a 4 wire from the 30A outlet and run the neutral then you can add 120v outlets to the octopus distribution box. Or if you really want to go big cut into the drywall and mount a nice 50A outlet on a 50A breaker. Not only will 240 @ 50A provide you with plenty of power, you can pick up a dryer feed cable for cheap out of the bins at Goodwill and use that for your power distribution box. And it is handy if you ever want to charge an electric car. And another thing you can often find those "tombstone" Lincoln stick welders for very cheap and those are great welders to use while you are saving up for a decent tig not some Chingtau tig that falls apart. And you CAN stick weld aluminum.

Once a few years from now your shop layout settles down you can then replace the octopus with EMT and put in 120 and 240 outlets spaced where the final resting place of each tool will be.

Lastly, consider buying an air compressor early on. Used ones are inexpensive and you can run smaller tools like hand drills and air ratchets off compressed air. And you will definitely want a compressor for running an HPLV gun and spraying paint, lacquer, etc. And nobody ever said "dang this air compressor I bought is just too big" so don't get a small one like one of those dumb pancake ones that is only good for running a nailgun. I have a 20 gallon in my wood shop and a 60 gallon in my garage (in my other house) that I bought for working on cars that is permanently bolted to the floor, wired into 240, and many times over the years I wish I had spent the money for a 2 stage one that could go above 120psi.

  • 1
    While I agree with much of what you said, I don't think you've properly addressed over-current protection, esp. on the 120 volt "trick" outlets. Also, instead of a bunch of temporary stuff, I'd suggest a dedicated sub-panel for the shop and WireMold 4000 raceway along the shop wall. Very flexible for future changes and no loss of initial investment in a temp setup. Also agree that whenever possible, run the tools at 240v. Lastly, the OP said he didn't plan on using high amp draw tools at the same time, but a dust collector is almost always used at the same time. Commented Dec 4, 2020 at 10:02
  • Thank you for the responses! Forgot to mention that the my shop is a two car garage with only one 120V outlet and behind that wall is a boiler room with the breaker box. The shop vac is - Vacmaster Professional - Professional Wet/Dry Vac, 16 Gallon, Beast Series, 6.5 HP, 120V
    – MrBaku
    Commented Dec 4, 2020 at 14:16
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    @Tim that's an idiom of the UK and commonwealth. Up on the pole is 3-phase "wye" power, ~400V leg-leg, ~230V leg-neutral. That is the normal household current for everything. Normally a house gets 1 phase but if they have large needs, they can get all 3 phases. Separately from that, for construction sites they use a special "55V/110V split-phase" (yes, read that twice) transformer, with center ground, giving 2 legs with 55 volts from either leg to ground. That runs special 110V tools. See how that's safer? Only 55V to ground instead of 220V. Commented Dec 4, 2020 at 16:46
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    @Tim I don't know about "expensive", NEMA is so laughably cheap here in the States that even with shipping... But there are a couple problems with C13/C14. First, it's not keyed for voltage. If you had a C14 plug (huh?) on a 110V appliance, nothing would prevent you from plugging it into a 220V source. Second C13/14 isn't rated for the current a 110V tool would draw. Also C14 "plugs" (what that they are), are made with an outer sheath, that won't play well on construction sites, it'll fill with dirt. I gather you think you're too smart to need keying? Commented Dec 5, 2020 at 18:21
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    @Harper-ReinstateMonica - shipping fom US to UK isn't cheap, plus taxes. If I was not smart, I'd have used C13 before. Still alive, so obviously (?) didn't. C13/14 are keyed for 'hot' situations, at 13A, but I already use the extra keyed ones for higher current use. Mud and dirt don't abound in my workshop - at least not for last 40 yrs, so that's not the problem! And the big yellow plugs (male) can get crud stuck, but they're still allowed. So, I search for a small plug/socket capable of 110vac, but as I have at least a dozen tools, they need to be cheap.
    – Tim
    Commented Dec 5, 2020 at 18:51

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