Another Electrical Question

[Matthew Poeller]

I have seen a bunch on the board as of late so here is another before all the electrical guys go to bed or hit their quota.

I purchased one of the Grizzly G0513X2s and now I am running a 220 line for it. The breaker size they recommend in the manual is 15 amps on 220. Is there any reason that I cannot use the 20 amp 2 pole that I already have (bought for another project but never used)? This one does not seem to have overload protection at the motor, that I can see. I guess the only thing I would be worried about is frying the motor.

I am also planning on converting my TS over to 220 and the recommend breaker at 220 is 10 amp. Is it bad to have that running on a 15 or 20 amp breaker? That one already has overload protection right on the motor so I do not think that is a problem. I am never going to run them at the same time so I am going to use the same circuit.

Thanks,

Matt

[Don Abele]

Matt, pretty sure you'll get a "few" replies to this one...here's mine.

Breakers are designed to protect wiring, not the devices they are powering. With that in mind, that means the number one concern is that the wiring going from that breaker to the outlet is sized correctly. Also, the outlet can not be oversized for the breaker (you can't use a 30 amp outlet on a 15 amp breaker).

With that said, you can run your 15 amp band saw on a 20 amp breaker and your 10 amp table saw on a 15 amp breaker without any problems.

It's highly unlikely you will burn your motor out...you would have to stall the blade and leave it like that for more than the couple of seconds that most of us would take to turn the machine off.

Be well,

Doc

[Von Bickley]

Matt,
The 20 amp circuit will work fine. Just be sure to use the proper size wire.

14/2 w/ground = 15 amp
12/2 w/ground = 20 amp
10/2 w/ground = 30 amp

[Anthony Whitesell]

Don has it right. The breaker, wire, and outlet sizes must be matched, and the size has little to do with the load, other than the load must be less than the breaker size.

I have just installed a 220 20amp outlet with 12/2 wire and an L6-20 outlet for my G0513X2. I also left myself an extra 8-10 inches in a 'special' spot, so I can add a junction box and drop for a second 220 outlet to run the jointer, if I get one that runs on 220. Oh, wait a minute, it arrived last week. :D Looks like I'll be visiting the borg electrical department sometime soon.:cool:

[Matthew Poeller]

Thank you very much. This makes sense then. I was just thinking that the breaker would provide some motor protection as well.

The one good thing that comes out of this is that I can take back the 10/2 wire that I bought the other day (expensive) and go with the 12/2 wire that I am already have. So I guess that is good news. Everything else that I bought is matched.

I would have known that about the wire had I looked at the electrical book before I went shopping.

Thanks,

Matt

[Rick Christopherson]

Thank you very much. This makes sense then. I was just thinking that the breaker would provide some motor protection as well. If your motor was running at a load sufficient to trip a 15 amp breaker, but not a 20 amp breaker, then by the time the 15 amp breaker tripped, the motor would already be fried. So the 15 amp breaker is not going to give you any protection from burning up the motor. The windings inside the motor are much smaller than 14 gauge wire, and you will burn the insulation before you reach 15 amps for a prolonged period.

Before someone jumps on what I wrote, consider that this condition would require that the motor was operating at 150% of its rating, but has not stalled, which is not likely to happen. The full load rated amperage of the motor is 10 amps. If the motor was so over loaded that it stalled the motor (most common point where the motor needs to be protected) then either a 15 amp or 20 amp breaker will trip because the amperage is going to be well over 20 amps.