Wiring a 1.5HP Tablesaw for 240V - Wire/Breaker Size?

[Peter Rausch]

I've read that running a 240V supply to a 1.5hp Tablesaw can often make the saw perform a bit better. Im just rewiring my shop so now is a good time to sort this out.

My Tablesaw is rated at 120 V / 240 V AC, 13 / 6.7 A. What type of wire do I need to run to power the tablesaw on a 240v circuit? Also what type of breaker?

[Rollie Meyers]

14 AWG NM cable & a 15A two pole circuit breaker of the same make as your panel would be the bare minimum,I don't use 14 AWG for anything other then residential lighting & for control wiring so 12 AWG would be what I would use w/ a 15 or 20 A circuit breaker, no neutral is required so 14/2 or 12/2 is fine.

[George Bregar]

While Rollie is correct, just run 12 to 20a breaker.

[Jason Roehl]

It won't make a lick of difference on your table saw. To change a saw from 120V to 240V you have to change how the current flows through the windings. Whether or not the saw is wired for 120V or 240V, the windings only ever have 120V across them.

But, since you're re-wiring your shop, I would at minimum run 12 AWG wire on a 20A breaker, as that would allow a future upgrade to a 3 HP table saw (or other machine). Even if you leave it 120V, make it a dedicated circuit, then you could easily change the circuit to 240V in the future by swapping out the receptacle and the breaker.

[Rod Sheridan]

Peter, as Jason indicated unless you are experiencing excessive voltage drop, changing your saw to 240 volts won't make a difference.

If you are going to re-wire I suggest going to a multi-wire branch circuit with a 2 pole 20 amper breaker, and use a 6-20R and 5-20R receptacle in a 4" square box. This will give you a 20 ampere 240 volt circuit and 2 X 20 ampere 120Volt circuits in one location. You will need 12/3 wire for that and it's the most efficient and versatile wiring method.

Regards, Rod.

[Von Bickley]

Peter,
Rod and Jason are correct with their replys. A lot of people get hung up over the 120/240 volt issue and don't really know what they are talking about. I'm a retired electrician and I run my saw on 120 volts..... WHY? If I have to load up my saw and take it to a job site, I don't have to be looking for 240 volts or changing out the saw.

[Lee Schierer]

Jason, Rod and Von have it correct. Changing to 240 will not improve the performance of your saw unless you are seeing a significant voltage drop on the 120 volt circuit it is on due to long distances.

If you are rewiring, it isn't worth the difference in cost to use 14 gauge wire instead of 12 gauge. You can run 12 gauge on a 15 or 20 Amp breaker, but can only run 14 gauge on a 15 Amp breaker.

[glenn bradley]

+1 on 12ga and a 20a breaker(s). That way the circuit can be used for a wider variety of other things later if that happens. I have run my 1-3/4" HP saw at 120v and at 240v. No noticeable performance difference at that HP. It happens to be running 120v right now; its a non-issue for my saw. YMMV.

[Dave MacArthur]

I find that folks posting questions like this usually turn out to be "amp limited" in their workshop... If you're asking this question, you usually haven't wired up a sub panel etc.
And therefore, I think (for non mobile users), the best answer is to wire it 230V thereby minimizing the amp draw and allowing you to run all your other stuff. 12ga 20A CB. Too many 115 V things and you really start pushing the amp loads for most shop feeders, I see a TON of folks posting about feeding with 60A CB to 100A sub panels.

[Chip Lindley]

Those who have non-issues with 1.5hp motors run on a 15a, 115v circuit are good to go! BUT, there are many extenuating problematic circumstances. Lots of shop spaces are not blessed to have dedicated 115v shop circuits for machines. ONE 115v circuit shared with other draws may not allow the 1.5hp motor to receive full amperage OR forever be plagued with nusiance trips when the going gets tough! That was just my situation with a Rockwell Model 10 contractor's TS. Switching it to 230v made all the difference.

Over 20 years ago I needed to provide 230v in the garage for a Rockwell 2hp planer and 2hp DC, so added a 100a branch panel. I got more bang for my buck running 230v receptacles around the garage, than adding redundant 115v plugins. Room for expansion! I outgrew the 1.5hp TS long ago. 230v allows running my 3hp PM66 without any further modifications to the 20a circuit. Come to think of it, most all of my machinery is 2hp or more now. I'm glad I thought ahead.

My 115v outlets are for incidental needs; battery chargers, corded hand tools, a 1/3hp shop fan, portable compressor, etc. Overhead lighting still shares the same circuit.

[glenn bradley]

I find that folks posting questions like this usually turn out to be "amp limited" in their workshop

Good point Dave. I have not reacted as though that might be the problem in the past and will factor that into my thinking in the future. When folks start talking 240v, I just assume they added a panel as many stock panels do not have the available slots for the double breakers around my suburban wasteland ;-) Amperage reduction is a good possibility.