2 HP motor on 110 Voltage

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Forum topic by ckorkyrun89 posted 08-19-2013 02:59 PM 1506 views 0 times favorited 5 replies Add to Favorites Watch
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60 posts in 1447 days

08-19-2013 02:59 PM

I just inherited my Grandad’s older Craftsman tablesaw. At some point he upgraded the motor to a 2 hp motor also from Craftsman. He had it wired for 220 but at my apartment garage I only have access to 110. The motor can be wired for 110 but has a big warning sticker saying it needs a 30 amp circuit to work.

Oddly enough there is a 1 pole 60 amp breaker in the panel but I can’t imagine that the circuit is wired to handle that much. I know which outlet in my garage is connected with that circuit. I also read that I need a minimum of 10 gauge wire to make the 30 amp circuit safe. If I find that it is wired with 10 gauge wire is there anything else I need to look for before trying this?

Also, 30 amps seems high for 2 hp. Is the 30 amp requirement just for startup so the circuit does not blow everytime?

I am pretty excited about the saw. Although it is a contractors saw it seems much heavier compared to my dad’s 80’s craftsman saw. I will probably have more questions regarding alignment of the saw but for now I need to make sure I can get it running first.

Thanks for any help.

5 replies so far

View Loren's profile


8178 posts in 3072 days

#1 posted 08-19-2013 03:07 PM

I’ve started 110v motors up to about 19 amps on a 20
amp breaker. 2hp rated motors tend to be about
22-24 amps but check yours.

View crank49's profile


3979 posts in 2395 days

#2 posted 08-19-2013 03:56 PM

The 30 amp requirement is fairly common for a true 2 hp motor on 120volts to prevent nuisance tripping during startup. Especially allowing for low voltage incoming from the utility company during high load periods.

If you have a 60 amp single pole breaker that is a strange one. Not very common. If it is connected to an outlet the outlet should be a special outlet to handle that kind of current and the wire should be 6 gauge. Otherwise it is not to code and needs to be removed. It is a fire hazard; very dangerous to have a 60 amp breaker on less than 6 gauge wire in the wall.

A 30 amp, 120 volt circuit should be wired with 10 gauge wire and the outlet for this circuit will have special slots, usually horizontal slots. This is to keep anyone from plugging an appliance that requires 30 amps into an outlet that is only rated for 15 or 20 amps.

If that saw switch circuit and motor could be wired for 220 volts, and I had to do any breaker replacing and/or wiring changes anyway, I’d change it all over, and install a 220 volt outlet. You would only need a 15 or 20 amp 220 volt circuit to handle that load and that requires a 14 or 12 gauge wire, respectively..

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

View gtbuzz's profile


427 posts in 1866 days

#3 posted 08-19-2013 05:05 PM

You don’t see 2hp (real 2hp not “2hp-ish) on 110 too often largely because it usually requires a 30A circuit. This Grizzly bandsaw has a 2hp motor and can be run 110. According to the manual, it’s got a FLA draw of 20 amps. That’s about what I would have guessed. Loren’s 22-24amps isn’t totally out of the question either, it depends on how efficient the motor is. You generally want your amp draw to be less than 80% of the breaker capacity, so 30A makes sense.

As far as the existing 60A breaker, if you’ve got any doubts about the wiring, absolutely do not use it until you can verify. As crank49 said, you need 10 gauge wire for a 30a circuit and 6ga for 60.

View ckorkyrun89's profile


60 posts in 1447 days

#4 posted 08-19-2013 08:39 PM

Well off the top of my head I am pretty sure that neither of the slots on that particular outlet is horizontal. I will check when I get home but it sounds like I might just be better off getting a different motor.

As I live in an apartment complex, there is nothing I can do to change the wiring to 220. I have a feeling they threw a 60 amp circuit breaker in there because there are 6 garages in a row and the way it looks like everything is wired, all of the door openers go to one circuit. I bet that someone in the past got upset that their door wouldn’t open when someone elses was opening and they just put the biggest breaker they could find in.

View crank49's profile


3979 posts in 2395 days

#5 posted 08-19-2013 11:10 PM

You know, if the apartment owner/manager put, or had someone else put that 60amp breaker on a circuit with 12ga or similar wire they broke the law. They are putting you at risk along with everyone else in that complex.

If you plugged your saw into that circuit it would run just fine I’m pretty sure. It would only use a surge inrush over current for a second or two when you start it up, and that is not going to overheat any wires.

The problem could be if you had a malfunction or short or burned bearing or similar. That could over heat the wiring and the 60 amp breaker would not trip. The wires could ignite inside the walls.

The bad thing is that could happen right now with the door openers or with any motor you put on the saw and plugged into that outlet. Or, any appliance that anyone else uses that circuit on. This is very dangerous. If I was living there and could confirm that there is a 60amp breaker feeding an undersized circuit they would fix that sucker or be damned.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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