30 amps for Jet JJP-12HH

[Mike Watts]

Howdy,
I am thinking of buying a Jet JJP-12HH. I have 12-2 wiring in the shop that is on a 20 amp circuit for my Delta Unisaw and Steel City Band Saw. The manual for the JJP calls for a 30 amp circuit breaker. My questions are 1) if I replace the 20 amp breaker with a 30 amp breaker am I endangering my other tools on that circuit? I of course only run one of them at a time. 2) Conversley, would it be ok to put the JJP on a 20 amp breaker or is the surge load greater than the 20 amps as suggested by the 30 amp rating?
Thanks,
Mike

[John Cooper2]

12-2 wire will melt with a 30amp breaker, bet you will need to replace it with a 10gauge wire

[Curt Harms]

I have the straight knife JJP-12, it's fine on a 20 amp. circuit. Seeing as you have an existing circuit, I'd probably use it and see how you get along. If the CB trips, you'll need to run a new 30 amp circuit. DO NOT under any circumstances just put a larger breaker on you existing circuit assuming the 20 amp circuit is 12 ga. wire. Some people here run 10 ga. wire when they run a new circuit even if it's 15 or 20 amp. If they want to make a circuit 30 amps in the future, all they have to do is change the CB, the wire size is adequate. You can oversized wire for a given ampacity e.g. use 10 ga. wire for a 20 amp circuit, you can't undersize. The function of breakers is to protect the wire and devices in the walls and keep them from overheating and starting a fire. An oversized breaker will not do that.

[Richard Jones]

I have the straight knife JJP-12, it's fine on a 20 amp. circuit. Seeing as you have an existing circuit, I'd probably use it and see how you get along. If the CB trips, you'll need to run a new 30 amp circuit. DO NOT under any circumstances just put a larger breaker on you existing circuit assuming the 20 amp circuit is 12 ga. wire. Some people here run 10 ga. wire when they run a new circuit even if it's 15 or 20 amp. If they want to make a circuit 30 amps in the future, all they have to do is change the CB, the wire size is adequate. You can oversized wire for a given ampacity e.g. use 10 ga. wire for a 20 amp circuit, you can't undersize. The function of breakers is to protect the wire and devices in the walls and keep them from overheating and starting a fire. An oversized breaker will not do that.

Can't argue with this, good sense for sure. Also, looking at the motor data from Jet, they claim 12.5 amps. I'd try it as is, too.

[Bas Pluim]

I have the same machine (helical head). It runs fine on a 20 amp circuit, I've never tripped the breaker. The motor plate states something like 12A, I'm not sure why the manual says you need a 30A circuit.

I would not put a 30A breaker on 12 gauge wire.

[Michael W. Clark]

Could it be that the manual is giving a 110V amp rating and the motor nameplate is 220V? Forgive me, I am not familiar with that particular tool. However, 30A seems like a big Safety factor for 12A FLA.

Eitherway, as the others stated, the breaker has to protect the wire. You can't just upsize the breaker unless the wire will handle the extra ampacity. If you get CB trips, you may have to upgrade the service to 30A but that would require looking at the wire and breaker size. Most of the time, 12ga is 20A, and 10ga is 30A. Based on the information provided, it seems like 20A would work.
Mike

[Ron Natalie]

I've got the JJP-12HH plugged into a 20A/240 circuit. I've not had any problems.

[Mike Watts]

Thanks for all the replies. I will take the suggested route of using it on the existing 12/2 and 20 amp breaker and see what happens. If I need to change the breaker I will also change the wire. Thanks again.
Mike

[Curt Harms]

I have the same machine (helical head). It runs fine on a 20 amp circuit, I've never tripped the breaker. The motor plate states something like 12A, I'm not sure why the manual says you need a 30A circuit.

I would not put a 30A breaker on 12 gauge wire.

I think Grizzly manuals used to do the same thing, recommend a 30 amp. circuit for a 3 h.p. 240 volt machine. I don't know if they still do or not.