240v mig welder breaker question


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Old 05-07-09, 07:59 PM
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240v mig welder breaker question

Hey, Ive bought a small 240 volt mig welder for home use, Its a Hobart 187, about 27amp draw.
Ive got a double pole 50 amp breaker and some 6-3 to run a dedicated line. My question is this, My 200 amp service is a cutler-hammer, It has two buses one on the left of the breakers and one on the right, How do I tell what bus is ground and what bus is neut? they both look like ground to me
Thanks
Danny
 
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Old 05-07-09, 08:33 PM
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If this is the first OCPD either bus can be used for ground or neutral since they are both bonded to the box. If not the first OCPD the bus screwed directly to the box with no insulators is the ground. Why are you using a 50a breaker when the load is 27a. Is this to a detached building. Are you installing a subpanel.
 
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Old 05-07-09, 09:00 PM
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First off. I know you are a homeowner and don't understand our terminology, but you need to learn. The neutral and ground connection points are referred to as 'bars'. The 'buses' are the metal bars down the middle which the breakers attach to. Yes, I know, you can have neutral buses etc, but not in a residential loadcenter, so to speak. In most all applicatons (again, I talking residential here), the neutrals (white wires) and the grounds (green or bare) all may attach to the same place, the neutral bar. You won't necessarilay have a ground bar, since the box is bonded. If you have a Cutler Hammer loadcenter, either light brown (CH series) or gray (BR series), both vertical bars on either side of the breakers are neutrals. The ground bar, if there is one, will be located off by itself.

There is nothing wrong with using 6/3 with a 50A breaker for a 27A load. However, you could downsize to 8/3 and a 40A breaker if you wish.

Circuit breakers are designed to indefinetely hold only 80% of the rated amperage. So in other words, you may only load a circuit breaker to 80%.
 
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Old 05-07-09, 11:58 PM
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Actually you wouldn't need 8-3 in most cases. I think that was a typo. 8-2 should do for a straight 240v welder. If this is a detached building though and you already have 120v to it you can't add a second circuit. In that case at least 6-3 and a subpanel on a 50a breaker is the way to go.
 
 

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