Help on 220V power cords

[Keith Albertson]

Well, I finally have my Sawstop all set up and ready to go. The problem is that the plug on the thing will not fit my 220 receptacle. I've been to Lowes and HD, neither have a socket that will fit the cord. I don't really want to chop up the cord to change the plug, but I did buy a matching plug.

Before I chop up the cord on the saw, has anybody made a 220V cord themselves? I've got the plug, I just need to know what kind of wire to use. I need about 9 to 10 feet of cord, the circuit is rated for 50 amps, the saw motor draws 13 amps.

Any advice would be appreciated, and might save the time delay of an electrician visit.

[Mark Amato]

You'd want to run at least 10GA SO SJT type wire per NEMA. Tons of places sell it. If you're in a weird environment you'd want to get oil-resistant or ruggedized cable.

You'd want at least an L6-15 type plug. When doing industrial design, it's always best practice to size the receptacles BELOW the current capacity of the wire used on it. Furthermore, using a 50A breaker on a 15A draw is kind of bad from an electrical perspective. In a perfect world, you'd have a 50A upstream breaker feeding a subpanel that has circuit breakers sized appropriately per the load. You'd want breakers that have an inrush current profile if you were going to do it that way. It's how we do large electromagnet power drops in the semiconductor world.

To answer your original question: 3 conductor 10AWG SO SJT, wire it into a Hubbel L6-15 making doubly sure to ground it correctly, wire it to the switch using QD connects or wire nuts, go cut wood.

EDIT: forgot this is a house. You want a 4 wire plug for an additional safety ground, not a 3 wire L1 L2 N. Ground the G wire to the table saw chassis.

[Clark Harbaugh]

When I made my cords for my table saw a dust collector, I matched the cord to the circuit size. However for a 50 amp circuit, that would require a 6AWG wire.

[Mark Amato]

When I made my cords for my table saw a dust collector, I matched the cord to the circuit size. However for a 50 amp circuit, that would require a 6AWG wire.

Exactly, which is why you really want to use a subpanel. Not that you can't do it the way that is being described, but you're using the wire as a fuse.

[Dick Brown]

Not sure what you are doing but if I understand your setup, please don't run your saw on a 50 amp breaker. If anything were to go wrong like stall your saw some way, you will have meltdown on a motor or cord that is rated for 13 amps. The one thing that might save the day is if your mag switch has protection in it but that won't save the cord if you had a short of some kind before the heaters. In my shop, I have my 3 hp saw running on circuit that was put in for a welder (#6wire?) but just changed the 50 amp breaker to a 20 amp, 220volt.
Dick

[Jim O'Dell]

I don't think it's any big thing to do. Just match the size of the wire, or go bigger. Match the male and female ends you need, and put it together. Personally, I'd rather replace the whole wire. That's what I did on my new table saw. I needed a total of about 22' to go over, up with the ducting, and over to the plug in. I jumped from what looked like 14 guage from the factory, to 10 guage heavy duty cable. Electricians, does SPJ cable sound right? Anyway, it's way overkill, but I like it. I purchased a 12 guage extension cord for my contractor saw when I changed it over to 220. Again, overkill, but it makes me happy. Jim.

Edit: I looked right past the breaker size. I'm running a 30 amp breaker on mine. It may be too big for what I need, but I'd think 50 amp would be overkill for sure. Can you change it to a smaller breaker?

[Tom Veatch]

If you're at all interested in complying with code, the outlet must match the breaker. If you have a 50amp breaker, the outlet must be a NEMA ?-50R as well. If you reduce the breaker size, the existing wiring (if compliant with the 50amp breaker) is fine, but you'll have to replace the outlets to match the breaker size, and you may have trouble fitting the wire to the connections of a much smaller amperage outlet. You absolutely do not want to put a NEMA 6-15 outlet on that circuit without dropping the breaker to 20 amps or less.

As long as the breaker, wire, and outlets are compatibly sized, there's no more danger plugging a 15 amp load into a 50 amp circuit than there is plugging a 5 amp load into a 15/20 amp circuit.

[Myk Rian]

You can run it with 12 gauge. Of course 10 is better, but for a short run you'll be OK. Look for some "Super service" wire. That's thick extension cord.

[Hugh Jardon]

Breakers are not a "bigger is better" thing. They need to be matched to the load. Once the load exceeds the rated current of the circuit, it should trip and prevent damage/fire/injury/death from excess current. I simply do not understand why plugs are not fused in the US. You can plug a 5A coffeemaker into a 50A circuit, and if a fault develops, it could be well ablaze before 50A. If the 5A coffeemaker had a 10 cent fuse in its plug, and was plugged into the same duplex receptacle as a 15A device, the 15A device would continue even when the 5A fuse blew.

To the OP - You should match the plug to the outlet, not the outlet to the plug, the building is much more important than what it contains, in general. A new saw is not going to be worth less if you change its plug to one that matches your outlets. You could always put back the original kind of plug (but not the original, if molded).

[Keith Albertson]

Thanks for all the input. It is clear I do not know "jack" about electricity. I went down to the shop, and the outlet, installed by the contractor who finished my basement, says 30 amps. I went out to the box in the garage, and the breakers for "220 shop outlet" are two 30 amp breakers ganged together. Does this mean this is a 30 amp circuit? Or is it really more and the 30 amp outlet is undesized? If so, I think I better call an electrician.

I think I can find an appliance replacement cord to wire into the sawstop that will fit my outlet. But since I already have a replacement plug to match my current outlet, can I just get the 10 guage wire Mark suggested? That way I can make it the length I need (less than 12 feet). The Sawstop manual says I only need 14 guage wire for less than 25 feet, but that doesn't sound stout enough to me.

Thanks again, I'm learning a lot from all this discussion. Any suggestions on an easy-to-understand book about wiring?

[Clark Harbaugh]

you have a 30 amp circuit. Basd on that, 10 AWG wire is fine.

If you google "220V wire size" you can find a number of sites that will help you with wiring size, plug types, etc.

[Peter Quinn]

Thanks for all the input. It is clear I do not know "jack" about electricity. I went down to the shop, and the outlet, installed by the contractor who finished my basement, says 30 amps. I went out to the box in the garage, and the breakers for "220 shop outlet" are two 30 amp breakers ganged together. Does this mean this is a 30 amp circuit?

I doubt there are two 30A breakers "ganged" together in your panel. A 220V breaker will take up two slots in the panel, and both of those slots will be "joined" with one switch as a single breaker, that in your case should read 30A. That is a single 220V 30A circuit, and should be fine for your TS.

I'd change the receptacle and/or the plug as you desire, just make sure as noted above that the wire is sized to handle the load the breaker allows, that the breaker is sized to deliver the load required (or it will keep popping), and that the receptacle and plug are sized to the breaker. I run a 1HP feeder (7A) on a 30A circuit, no problem. Your machines should have their own circuit protection. The breaker is generally designed to protect the wire,and thus your house, and NOT your machines!

I knew a guy that got a good deal on some 8AWG wire and used it to wire his whole shop. A bit much, but not dangerous. Too big a gauge of wire wont hurt you. I met a guy that used an electric range circuit to push a TS, just changed the outlet to the 30A he needed. Should have changed the breaker too, but not the end of the world as I see it. I knew another guy that threw a 30A breaker on a 20A circuit to push a bigger machine. and that guy is asking for real trouble.

[JohnT Fitzgerald]

Keith - the SS manual had a section on how to replace the cord. The instructions were, as I recall, pretty good.

I believe you needed 14ga 3-conductor (2 hots and a ground). you do not need 4-conductor, as you do not need to run the neutral for the SS.

If it were me, I would replace the breaker with an appropriate 20A breaker; get a matching receptacle (6-R) and plug (6-P) rated for 220v 20A; and use the proper gauge wire at the length you need, as specified in the SS manual. I did not cut into the plug that came with my saw, I just replaced the entire thing. It's easier if you remove the main box from the saw when doing the work.

[Mark Amato]

So long as you're grounding the table saw body (and motor housing) via a ground drain, you can use L1 L2 N 3 wire. If you aren't, you want to use a L1 L2 N G config and bring the earth to the saw body. The G should be a separate wire from the N and go to your earth ground.

[JohnT Fitzgerald]

So long as you're grounding the table saw body (and motor housing) via a ground drain, you can use L1 L2 N 3 wire. If you aren't, you want to use a L1 L2 N G config and bring the earth to the saw body. The G should be a separate wire from the N and go to your earth ground.

The SS manual clearly requires 3-conductor (L1 L2 and G) and there are are no reasons to worry about a N(eutral), or about getting the G(round) to the body. A simple 3-conductor cord (2 hots and a ground) to replace the one installed on the saw, and attach them to the same places in the switch box. Any needed grounding of the body and housing etc should already be all done by all the other internal wiring in the saw.