Breaker size?

[michael gates]

What size breaker and wire do I need for a 3hp tablesaw?

[Brian Cosgrove]

20 amp breaker with 12 gauge wire should be fine

[Dan Hintz]

20A with 12 gauge... although personally I'd install a 30A with 10 gauge.

[Dave MacArthur]

Same as Dan, 20A w/ 12 gauge, but I'd just run 10 gauge and use 30A instead. That "future growth" lesson has been learned by every guy to ever wire up his woodshop, no reason for you to re-learn it youself

Here's a thread on motor wiring if you're interested in reading some NEC arcana to arrive at the same answer as above

Sizing Wires and circuit breakers for 3HP and 5HP shop motor circuits

[michael gates]

"Here's a thread on motor wiring if you're interested in reading some NEC arcana to arrive at the same answer as above"

I'll just go with what you guys said!

Thanks everyone!

[Derek Voigt]

I have a 20A with 12 gauge wire and every so often I will trip the breaker on start up, even though it says 18Amp max on the motor.

[Dan Hintz]

Derek,

Could be a failing breaker... I've had some that were junk straight out of the box (even had a GFCI socket that was junk straight out... took me a while to figure that one out).

[larry bailey]

What voltage?

[Jim O'Dell]

3 HP, I think we would agree it has to be 220 volt.
I wired all my 220 plugs with 10 gauge, and 30 amp breakers. Wish I had run 8 guage to one of them on a 50 amp breaker for the welder, but I doubt it needs more than 30...if I ever learn to use it. Jim.

[Bernie May]

I ran 10 gauge wire for all my 220V except one line of 8 gauge with a 50A on it (future welder or some odd big electric draw). All of the 10 gauge have 20A breakers except the Dayton heater which has a 30A. If I ever get a machine with greater than 3 hp, then I can add 30A breakers on my 10 guage wire.

[Rob Russell]

I ran 10 gauge wire for all my 220V except one line of 8 gauge with a 50A on it (future welder or some odd big electric draw).

If you ran individual THHN/THWN conductors in conduit, then you're fine. If you ran #8 NM cable and are in a jurisdiction that's using the 2008 NEC, your #8 is only rated for 40A.

[Rollie Meyers]

If you ran individual THHN/THWN conductors in conduit, then you're fine. If you ran #8 NM cable and are in a jurisdiction that's using the 2008 NEC, your #8 is only rated for 40A.

The requirement that NM cable be sized from the 60 degree column of table 310.16 predates the 2008 NEC by many code cycles, it was added that SER cable be sized at the 60 degree ampacity in the 2008 edition.