# Electrical Question, Sawstop



## Grant_ (Feb 4, 2017)

I know little about electrical stuff, but I've done some research and I'm looking for guidance from folks who are more knowledgeable than me.

I am in a newly built house (less than a year old) and I had the builder run a dedicated 220 circuit to my garage, since I knew I would use it for my workshop. My table saw is the only device I will have plugged into this circuit.

I just got my Sawstop 3HP PCS assembled, but now I have two problems. 1) The plug on the end of the power cable (3-prong) doesn't match the wall receptacle (4-prong) installed by the builder, and 2) the power cord isn't long enough for me to move the saw out into the middle of the shop. Anyone else dealt with a similar problem?

The Sawstop manual has instructions for installing a new power cord, and I'm confident I can do that, but I'm looking for confirmation from experts that this is an OK approach.

The saw is only supposed to draw 13 amps. I checked my panel, and the builder installed a 40 amp circuit breaker. The outlet in my garage wall is rated at 50 amps. I can buy the right plug at my local Lowes that is also rated at 50 amps.

Is it really just as simple as buying enough length (20-25 feet should do) of the appropriate gauge 3-conductor cable (as required per Sawstop), connecting one end to the saw, connecting the other end to the new plug, plugging in the saw, and I'm good to go? From my research it looks like 40 amps requires 8-gauge wire. It looks like I can buy that at my Lowes as well. I'm guessing I shouldn't go any smaller than that, even though the saw only draws 13 amps?

Is there anything else I need to consider? I am very concerned about safety. I don't want to melt any wires, burn out any motors, or cause any fires. I spent the $$ on the saw to reduce the chances of chopping off a finger, it would stink if I electrocuted myself while setting it up. :-(

Thanks!


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## EugdOT (Nov 17, 2016)

Is it a outlet or a sub panel? You might be able to convert your outlet if the gauge is thick enough to Handel a small subpanel so you can run lines off it. I had simular situation when I got my sawstop, I originally ran several lines to the garage during a house Reno and had the electrical just convert the 220 line to a 60 amp subpanel so I could add a 220 so I could maximize the higher gauge line so off the 60 app I have 3, 220 lines I could run without taxing the main panel.
All you need is a 20amp breaker for the sawstop and a new receptacle. Then use the remaining amp amount for another breaker like something like a dust collection system. 
You will need this outlet either way 
Just a idea?


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## Grant_ (Feb 4, 2017)

Thanks for the reply. To answer your question, it's an outlet not a sub-panel. I'm told that local building codes require 4-prong outlets on 220 lines. Based on that, it sounds like I'm stuck replacing the plug on my SS.


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## wapakfred (Jul 29, 2011)

A lot of folks run their 240V tools off dryer outlets and other receptacles that are oversized for the service. You don't need to size your extension to the outlet, instead size it to the motor. So all you need to do is get some #12 wire (SO or whatever service duty you want) put a 20 amp receptacle (6-20R) on the saw end for the saw plug, and put a plug on the other end that will use the 2 hots and the ground (the neutral on the plug will be unused). Plug everything up and you're good to go. Of course, there's several dozen other ways to do this as well (including changing to a sub panel…good idea actually), but this is probably the easiest. Ask here about the wiring hook on the plug up if your unsure.


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## clin (Sep 3, 2015)

I simply made an extension cord for mine, just as Fred described. Build the cord to match the load (the saw). Assuming it's a relatively short cord 20 ft, not 200 ft. Use the largest wire you can, that will fit the socket that matches the SawStop plug. Use whatever plug you need to fit your 240 V wall socket.

Also, those 4-wire sockets have two hot leads (that's 240 V across them), a neutral, and a ground. Your saw just needs the two hots and the ground. The neutral is in the socket because some loads might use both 240 V and 120 V. You get 120 V from each hot to neutral, and 240 between the hots. While the ground is more or less at the same voltage as the neutral. The ground is never meant to carry loads. So some loads need the neutral, to power any 120 V load that the 240 V equipment might have.

Your SawStop only needs the two hots for 240 V power and the ground for safety. It doesn't use a neutral. So you simply don't wire up the neutral on the wall end of your extension cord. Also, just get a cable with three total wires (2 hots and a ground).


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## brtech (May 26, 2010)

Yes, build a new cord. Get a plug to match your outlet. As above, size the wire to the load, but be generous: round down (AWG smaller number is bigger). If 12# is maybe close, then go 10#. 8# is overkill.

It's pretty easy to do, and there isn't much chance of electrocution. Wire it up, check with a multimeter that what you think is 220 is really 220, and turn it on.

The only safety issue was covered above: you want the ground (typically green wire, but don't depend on color), not the neutral. They are tied together at the panel, but you want the ground anyway.


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## sawdustdad (Dec 23, 2015)

Go ahead and make up the adapter cord, but a better solution is to put a subpanel where your 50A outlet is. Then come out of that with several circuits for various loads. Looks like you'd need an extension cord for your saw regardless.


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## WhyMe (Feb 15, 2014)

> Thanks for the reply. To answer your question, it s an outlet not a sub-panel. I m told that local building codes require 4-prong outlets on 220 lines. Based on that, it sounds like I m stuck replacing the plug on my SS.
> 
> - Grant_


4 prong outlets are only required on range and dryer circuits. They should not be required on all 240V circuits. That is senseless.


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## MrUnix (May 18, 2012)

> Is it really just as simple as buying enough length (20-25 feet should do) of the appropriate gauge 3-conductor cable (as required per Sawstop), connecting one end to the saw, connecting the other end to the new plug, plugging in the saw, and I'm good to go?


Yes.

Don't make it harder than it needs to be. Get a 25' foot roll of 10/3 (or 12/3) SOOW/SJOOW cable and the proper plug from the BORG and start making sawdust.

Cheers,
Brad


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## rwe2156 (May 7, 2014)

If you told him what you were going to do, he installed the wrong kind of outlet. Its on a 30-50A circuit depending on the wire size.

My suggestion is to change that outlet to a small sub panel. You will get a 240V circuit and 2 or 3 120V circuits depending on the panel.

This will be important when you find a need for a dedicated circuit for a compressor or dust collector.


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## pintodeluxe (Sep 12, 2010)

I'm not sure about the code in your area, but I would never breaker a 13 amp tool at 50 amps. 
I run my 3 hp PCS on a 20 amp breaker. I had the electrician run 10 gauge wire, in case it ever needed to be scaled up to a 30 amp (larger future dust collector?), but as far as the saw is concerned 20 amps is all it will ever see.


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## Carloz (Oct 12, 2016)

> I m not sure about the code in your area, but I would never breaker a 13 amp tool at 50 amps.
> I run my 3 hp PCS on a 20 amp breaker. I had the electrician run 10 gauge wire, in case it ever needed to be scaled up to a 30 amp (larger future dust collector?), but as far as the saw is concerned 20 amps is all it will ever see.
> 
> - pintodeluxe


Come on ! You do not need a 0.05A breaker to power your cell phone !
The breaker and the circuit must be greater than the load that is the only condition and no code can tell you otherwise.
Most saws and Sawstop for sure have an internal breaker that protect the saw. The one in the panel is there to protect the circuit not the tool.


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## TheFridge (May 1, 2014)

Don't know your setup.

I'd change the breaker to a 2 pole 30A

And the receptacle to a nema 6-30R (30A 250V straight blade). And if it needs a cord end a nema 6-30P.

If the receptacle says 125/250V, has 4 terminals, or has angle blades it the wrong one.

If you need to make an extension cord get a 6-30C and 6-30P (C is female, P is male, R is receptacle)

You could probably turn that feeder into a sub panel if you wanted but I wouldn't put anything in it that would possibly run at the same time as the saw.


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## wapakfred (Jul 29, 2011)

There's no code problems with doing that (running the saw on a 50 amp outlet) unless there are some really, really strange ones that are locally enacted.


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## runswithscissors (Nov 8, 2012)

Check the wire size on the SawStop. There's a chance its only 14 gauge. A lot of tools drawing 240v at less than 15 amps only use 14 gauge. But 12 gauge is fine too. Anything heavier is just a waste of money.


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## TarHeelz (Sep 13, 2012)

Easier for me than building a new cord would be to swap out the 50 amp 220 breaker with a 20 amp 220 breaker and then swap out the 50 amp 220 receptacle with a 20 amp 220 receptacle.

You'll know that you have the wire in the wall necessary for a heavier load if/when it's ever needed.

Tools needed: Screwdriver.


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## WhyMe (Feb 15, 2014)

> Easier for me than building a new cord would be to swap out the 50 amp 220 breaker with a 20 amp 220 breaker and then swap out the 50 amp 220 receptacle with a 20 amp 220 receptacle.
> 
> You ll know that you have the wire in the wall necessary for a heavier load if/when it s ever needed.
> 
> ...


You'll have a hard time finding a 220V breaker and outlet, they are 250V. Also you may have a challenge getting #6 wire in a 20A outlet. You may need to add smaller pigtails.


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## cathode (May 18, 2014)

> I m not sure about the code in your area, but I would never breaker a 13 amp tool at 50 amps.
> I run my 3 hp PCS on a 20 amp breaker. I had the electrician run 10 gauge wire, in case it ever needed to be scaled up to a 30 amp (larger future dust collector?), but as far as the saw is concerned 20 amps is all it will ever see.
> 
> - pintodeluxe


This is a really common misconception. The breaker is NEVER designed to protect the load. The circuit breaker protects the WIRE

If the load needs protecting, it needs to have an inbuilt form of protection (thermal shutoff, onboard miniature circuit breaker, etc). The manufacturer of the tool or device handles this part.


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## pintodeluxe (Sep 12, 2010)

My electrician taught me to breaker much closer to the load of the tool. Of course wire size factors into the equation. There is no harm in being overly cautious with electricity.

Would you power a 30 amp hot tub with a 100 amp breaker? It makes no sense.


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## pintodeluxe (Sep 12, 2010)

I'm beginning to think that the two weeks I spent training with a plumber in high school didn't prepare me to become an electrician. Ha! Good thing I hire out all my electrical work.


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## cathode (May 18, 2014)

> My electrician taught me to breaker much closer to the load of the tool. Of course wire size factors into the equation. There is no harm in being overly cautious with electricity.
> 
> Would you power a 30 amp hot tub with a 100 amp breaker? It makes no sense.
> 
> - pintodeluxe


We might be getting caught up on semantics, but I'm referring to how the NEC works with regards to breakers. Typically the NEC leaves it up to the manufacturer of a device to provide overcurrent protection for sensitive components within that device. The only time that NEC might get involved with a load device in this regard, is when you have a piece of equipment that is hardwired in.

To answer your question, I would not, because I would need #2 AWG copper (or #3 in certain cases), and that stuff is difficult to work with. I definitely could not land it on the terminals of a smaller device.


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## bearmannh (Jan 11, 2011)

As a licensed electrician I agree with other posters that are suggesting putting a loadcenter were the current 50 amp receptacle is. You can just install a cheap 12 circuit "Main Lug Only" loadcenter that will be protected by the 40 amp breaker at your main panel (Just don't bond the neutral to the equipment ground since this is a subpanel). From there you can nipple off of the panel and install a NEMA 6-20 receptacle with a 2 pole 20 amp breaker (The 20 amp receptacle will accept the NEMA 6-15 plug). You do not want to install a 20 amp receptacle on a 40 amp breaker as other posters has written. This IS a bad practice as well as a code violation of article 210.21(B)(1) of the NEC which requires single branch receptacles be rated not less then their branch circuit rating (Can't put a 20 amp receptacle on a 40 amp breaker).


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## cathode (May 18, 2014)

> As a licensed electrician I agree with other posters that are suggesting putting a loadcenter were the current 50 amp receptacle is. You can just install a cheap 12 circuit "Main Lug Only" loadcenter that will be protected by the 40 amp breaker at your main panel (Just don t bond the neutral to the equipment ground since this is a subpanel). From there you can nipple off of the panel and install a NEMA 6-20 receptacle with a 2 pole 20 amp breaker (The 20 amp receptacle will accept the NEMA 6-15 plug). You do not want to install a 20 amp receptacle on a 40 amp breaker as other posters has written. This IS a bad practice as well as a code violation of article 210.21(B)(1) of the NEC which requires single branch receptacles be rated not less then their branch circuit rating (Can t put a 20 amp receptacle on a 40 amp breaker).
> 
> - bearmannh


Don't forget that the subpanel needs a separate means of disconnection if it's not within line of sight of the feeder breaker, or if it's more than a certain distance from the feeder origination (6 or 10 feet, I can't remember)


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## bearmannh (Jan 11, 2011)

The panel does not need a local disconnect if it is in the same building. Local codes will supersede the NEC however so It may be worth checking into. That said there is no harm in putting a 40 amp backfeed breaker to act as a local shutoff. Just make sure you get a retainer clip for breaker.


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## Misfit2209 (Nov 22, 2017)

I have The same problem. I have a 6-50r nema for my welder in my garage on a 50 amp circuit, buying a band saw that needs a 30a circuit abd the saw that needs a 20a circuit. Would I run a 50a leg, 30a leg and a 20a leg? Would this overload the circuit in my panel. The wires in the wall are big but I'm not 100% sure what gauge. Is there a way to measure them ? Any help is greatly appreciated.


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## Bryangarry (Feb 11, 2021)

I just bought the same saw. I meant to get the 120 v. I am thinking about just rewiring the motor to 120 and put a 120 20 amp plug on it.


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## Wags999 (Jan 16, 2021)

The breaker should be the weak link in the whole circuit. Size of wire and size of what you trying to power would tell you what the breaker needs to be. If you install a 12ga cord on a 50 amp breaker you risk overheating the cord and potential fire. The breaker protects everything else on the circuit. And yes it is against code to attach a lower rated appliance (or tool) to a higher amperage circuit. The wire size will determine what is the largest breaker…Put the breaker the mfg of the tool recommends. Good luck.


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## WhyMe (Feb 15, 2014)

> ..... The breaker protects everything else on the circuit. And yes it is against code to attach a lower rated appliance (or tool) to a higher amperage circuit.
> 
> - Wags999


I don't know what code you are referring to, but the NEC only covers the circuit from the service to the outlet, not any appliances connected to it. The breaker is sized to the wire ampacity and the wire is sized to the potential load. Appliance's cords are sized to the load of the appliance not to the circuit size. I have plenty of power tools that have #16 cords on them plugged into 20A circuits wired with #12. So please point out the code that you are speaking of.


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## tvrgeek (Nov 19, 2013)

Blades for 220 and 110 will by definition not match. Lower CURRENT plugs should fit one size larger current receptacle. In other words, a 15A plug will fit a 20A outlet. It will not fit a 220 outlet.

Search "EMA receptacle" to see what plug is what.

Can your saw be wired for 220? If so, I strongly suggest it be on a 20A 220 branch. If it is a 110 only, then a 30A 110 branch. If the contractor gave you a 50A outlet ( for a cloths dryer) he was not doing you any favors.

Running a real table saw, you need a real dust collector. 3 to 5 HP minimum. So you want a dedicated 20 or 30A 220 for that.


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## MrUnix (May 18, 2012)

> And yes it is against code to attach a lower rated appliance (or tool) to a higher amperage circuit.


Funny that… pretty much EVERY appliance (or tool) you have is (or should be) attached to higher rated circuit. I'm pretty sure that isn't what you were trying to say ;-)

Cheers,
Brad


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## Lazyman (Aug 8, 2014)

> Blades for 220 and 110 will by definition not match. Lower CURRENT plugs should fit one size larger current receptacle. In other words, a 15A plug will fit a 20A outlet. It will not fit a 220 outlet.
> 
> - tvrgeek


And a 20A 110V plug will not fit a 15A 110v receptacle.

Bryangarry, the point is that it is a little more complicated than just switching the saw to 120 and adding a 20V plug. If I read it correctly, the amps at 220v are 13 so when you convert it to 120v, it will double to 26amps so you would need a 30 amp circuit and receptacle (which is not common) and that assumes you have no other significant loads on that existing circuit. You would be better off, IMO, just biting the bullet and have a 220V circuit (or two) installed. While you are are at, you might as well have another 120v circuit put in just so that you never have to worry about adding tools down the line.


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## WhyMe (Feb 15, 2014)

Lazyman you managed to reference 110V, 120V, 220V, in your comment. You forgot 240V.


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## KLF (Jan 25, 2021)

> I just bought the same saw. I meant to get the 120 v. I am thinking about just rewiring the motor to 120 and put a 120 20 amp plug on it.
> 
> - Bryangarry


If you bought the 3 hp PCS, I don't think this is possible, and it certainly isn't advisable. I just checked mine, and there is no 120V data on the motor name plate. I guess you could hack the motor, but then it will pull ~26A and it will probably run hot.

Someone else earlier said it correctly: the breaker in the panel protects the wire up to the final device(s) at the outlet, usually a receptacle. If there is only one receptacle, then it needs to be rated the same as the breaker. But, for instance, you can put several 15A receptacles on a 20A circuit, that's fine.

Saying "it's against code to attach a lower rated tool to a higher amperage circuit" is just nonsense. You do it all the time. Does that lamp on your nightstand draw 15amps? What about that RO sander that only draws 5 amps, but it's plugged into a 20A circuit? Please quote me the section of code that says this, I have the NEC book right next to me here.

Here's what I did. I have a 100A sub in my garage, and 2 2-pole (240V) circuits installed, one is a 20A for my air compressor, with a NEMA 6-20 receptacle. I also have a 40A circuit for my welder, with a NEMA 6-50 receptacle. I don't use the welder very often, but the compressor gets a fair amount of use.

Now I have a SS PCS 3hp (just got it home today), it has a 6-15P plug on it, but it is fine plugging it into a 6-20 receptacle. I'd rather not have to keep swapping plugs with the compressor, so I decided to use the 40A welder circuit for the saw. Meanwhile I found a great deal on a Jet 2hp DC, which I will rewire for 240V (draws 5.5A), installing a 6-15P plug. So, how to plug them both in at the same time?

I made a splitter adapter. Bought a 6-50P plug, a short piece of #10 SO cord, and put 2 6-20R receptacles in a 2-gang handy box. Now I can plug both into the 40A circuit.


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## Lazyman (Aug 8, 2014)

> Lazyman you managed to reference 110V, 120V, 220V, in your comment. You forgot 240V.
> 
> - WhyMe


LOL, I ran out of points to make. I wanted to work 115v in there too.


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## WhyMe (Feb 15, 2014)

> ........................
> If there is only one receptacle, then it needs to be rated the same as the breaker.
> 
> - KLF


Technically that's not correct. On a single receptacle circuit the receptacle can be larger than the breaker, just can't be smaller. See NEC 210.21(B)(1)


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## KLF (Jan 25, 2021)

> ........................
> If there is only one receptacle, then it needs to be rated the same as the breaker.
> 
> - KLF
> ...


You are correct, thanks.


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