Circuit breaker for big welder?

[bcarlson]

Hi guys,

I am picking up a Miller 330 A/B on Monday, and have been looking at the owner's manual online. I'm not an electrician, so I was hoping someone could help me out with a question. I have a Lincoln 175HD wirefeed welder, and run it on a 220v single phase outlet that has a 50amp breaker on it. I had this outlet and breaker installed when we built the house, specifically intended for welding, and it works great (I use it on the highest setting quite a bit).

Now, this new welder appears (but I think I might not be reading the specs right) that it requires a 125amp breaker. My question is, since I'm mostly going to be using it for low amperage stuff (sheetmetal to 1/4" steel), will I be able to use it for that off the 50amp breaker for a few weeks until I can get a bigger breaker installed, or will it pop the breaker when I turn it on?

Also, since my entire panel is only a 200amp panel, will the inspector even allow me to put a 125amp breaker in it?

Thanks in advance,

Ben

 

[sneezer41]

you do not need a larger breaker, I have a 175 amp TIG that I ran on a 60 amp for years, popped the internal overheat before the breaker.

Welding amps are not the same as breaker amps.

Look at the cord on the welder, bet it is 10 ga, maybe 8

 

[Jared]

you do not need a larger breaker, I have a 175 amp TIG that I ran on a 60 amp for years, popped the internal overheat before the breaker.

Welding amps are not the same as breaker amps.

Look at the cord on the welder, bet it is 10 ga, maybe 8

I have to disagree with this, sure you ran your 175 amp tig on a 60 amp, but the welder he bought is about double the size of yours. The cord on my 225 amp welder is 6 gauge. It will run fine on the lower setting but if you start cranking up the heat a bit it ll probably trip the breaker. BCarlson you are probably reading the specs right, i was looking at a old hobart similar to your miller and it required 125 amps. Have fun with the new welder.

 

[goodfellow]

I have to disagree with this, sure you ran your 175 amp tig on a 60 amp, but the welder he bought is about double the size of yours. The cord on my 225 amp welder is 6 gauge. It will run fine on the lower setting but if you start cranking up the heat a bit it ll probably trip the breaker. BCarlson you are probably reading the specs right, i was looking at a old hobart similar to your miller and it required 125 amps. Have fun with the new welder.

Correct! That welder was an industrial staple for more than 15 years and requires a heavy duty circuit. You can get the manual here

http://www.millerwelds.com/service/ownersmanuals.php

You will need the serial number though, because Miller made many internal changes to this welder. The serial number should be stamped of the front control panel and on the inside of the cabinet (in case the front panel is beat up). These machines have high duty cycles. Hence they were manufactured with huge copper wound transformers that require a lot of power. If you're not going to weld at very high amperages and duty cycles, (such as TIG welding sheet metal or stick welding up to 1/4" plate), then a 100 amp circuit might be OK. However, TIG welding at high duty cycles on heavier gauge aluminum sheet or plate takes a LOT of power and will require an appropriate circuit - so a 125 amp (or higher) circuit and appropriate gauge wire may be needed.

If I recall, this series of machine did have models with Power Factor correction. The PFC models required less amperage than no-PFC. If you have one with PFC, then that aspect may help in down-sizing the power requirements.

These are great welders, with no electronic controls or IC's to burn out. However, they are industrial machines and require appropriate installation.

 

[bcarlson]

Awesome guys, thanks for the info. This is the manual that came up for the serial number I was given...

http://www.millerwelds.com/om/o340h_mil.pdf

I'm not sure if it's the 200 or 300 amp version, but like goodfellow said, the duty cycle is 60% at 200amps output or 300amps output, respectively... it's ALOT higher than my little 175HD!!

If it's the 200amp version, it appears I can run it off a 60amp breaker, but the 300amp version says it needs 96amps (I think I'm reading that right on errata sheet, figure 2-1??). Please correct me if I'm wrong.

Thanks again guys,

Ben

 

[goodfellow]

I think the 320 model signifies 200 amps vs. the 330 which is 300 amps. I used to have the old catalogs, but tossed them when I moved two years go -sorry!

For more detailed info, just post your questions on the Miller forum. There are many folks over there that still use these machines on a daily professional level and they have a wealth of knowledge.

http://www.millerwelds.com/resources/communities/mboard/

I have a Miller Dialarc HF that is dated around the time of your model. I put is on a 100 amp dedicated circuit and it is an absolutely great welder. Nothing fancy about this equipment, but it'll weld day in/day out without any problems. The newer models might have more options, but they also require a lot more maintenance.

Good luck -- that is a great welder.

 

[Merkava_4]

You've got to find out what its input amperage is at its max output amperage. I'd want a circuit breaker to handle the input amperage at the machine's max output amperage. If I have it cranked up to 300 amps, and I'm pulling a 180 amps into the machine at a 100% duty cycle, I'd want to have a 200 amp circuit breaker.

I know 300 amps is double what you would need for most situations; I was just using that as an example.

 

[l_bilyk]

You will probably need a new circuit

 

[W-Cummins]

I ran my Syncrowave 351 off a 50 amp breaker for a few years and never had any problems with it. I say give it a try if it trips the breaker all the time you can upgrade if not your fine...

William...