[Rickster]

Got a deal on a Miller 330a/be and jumped on it. Now, after a few years of it sitting, trying to figure out if it can effectively be hooked up at the house. Options of running off the existing garage circuit which is 60amps and figuring out how to cap the machine so it doesn't exceed that, versus getting 30-40 feet of cable and tapping into the house 22kW backup generator. Complicated stuff before I can even start trying to TIG.

[entity-unknown]

You should mention the machine seems to require 100A for max output. It'd also help to say your Amp capacity at your main breaker. I think most newer homes max out at 100A across the main breaker from the power company feed but it's been about a year since I had to research that.

There's ways of bridging breakers but you are limited to your home's overall supply minus the existing use all the way down to your cell phone charger and sprinkler timer.

If you never plan to exceed I think it was suggested 276 welding Amps then you'll be within your existing outlets limits.

[MinnesotaDave]

I own one, excellent machines, 50-60 amps will run it on the midrange setting.

On a 60 amp breaker I've welded with mine at 230 amps AC tig for extended periods and the same for 250 amps on DC.

Try yours turned to the max on the middle setting, if it trips the breaker turn it down and try again - you'll find the max pretty easy.

[Rickster]

Excellent plan, thank you. Looking at a two day EAA course on TIG in Griffin, Ga next month just to get an idea of settings and the vernacular.
Ran across a Craigslist deal on wire that would upgrade the garage power from 50 to 100 amps for about $200. Hate to do that if just messing around and regular garage welding would do me for the foreseeable future.

[MinnesotaDave]

Personal opinion, 100 amps is the minimum for garage wiring anyway.

Plasma, with good compressor and lights will exceed 50 amps in many cases (my plasma draws 70amps at full load).

That doesn't even leave capacity for a shop fridge - no work occurs if I'm out of MtDew

[entity-unknown]

You might regret that Craigslist deal but depending on the wire gauge and length it could be a great deal. Romex is sold by a wire number +1 for ground. So if it's 2 wire Romex, you've got hot, neutral, and ground. If it's 3 wire Romex, you've got 4 total wires. Consider the plug/receptacle you need since that'll say how many wires you need.

If you want to know how much power your home has available, just look at your main breaker. If you have two 100A breakers, then you've got 200A capacity. If you've got two 50A, then you're got 100A capacity. You can not turn 100A into 200A for the main feed since your home is not an inverter and there are no capacitors.
If you've got the capacity then you're looking at around 0-3 gauge Romex wire and the length is what you need up to about 75Ft for 100A and 100Ft for 50A.
In nearly every situation you want install a 100A breaker at the box to give 100A to your outlet, if you are going to upgrade and/or need that full capacity of your welder. You might be able to upgrade to a 75A breaker without changing anything but make sure the load wires can handle it. Creative electrical solutions are a bad idea when you're above 15A and just always frowned upon. We call creative home electrical solutions "Mickey Mouse Shit".

[Poland308]

I think your calculations on the panel sizing might be wrong. The rating of your service is not equal to the size of the breakers in your pannel.

[Rickster]

Thanks, Entity-Unknown. I do 15amp myself. Above that, I am respectful to my electrician and address him as "Sir." The circuit for the welder has a coupled breaker with 60 on each leg, which I was counting as 60 amps available. Figured to get enough #2 to run two runs and a #4 for ground.

[MinnesotaDave]

Thanks, Entity-Unknown. I do 15amp myself. Above that, I am respectful to my electrician and address him as "Sir." The circuit for the welder has a coupled breaker with 60 on each leg, which I was counting as 60 amps available. Figured to get enough #2 to run two runs and a #4 for ground.

That is 60 amps available.

If you had a double breaker, with a single trip lever, it would still say 60 amps 240v.

[entity-unknown]

Josh, I wasn't saying the service is limited to the breaker box, but the house is.

If I'm not mistaken the power company dictates your maximum delivery capacity, then your power company meter dictates your home's maximum service capability, then your main breakers dictate your home's existing capacity, and then your sub breakers dictate the line and all the outlets connected to it's capacity with all sub breakers combined being limited to the overall main breaker capacity right?

Rickster, you're welcome! I'm no expert, just well rounded with some experience and a ton of research. The people here have helped me out immensely so I try to return the favor by offering hopeful sound advice to others I'd say you and Dave got it right and you'll probably be welding in no time! Just don't weld with the dryer on

[Poland308]

Breakers are sized to protect the wire. They are not an indicator of your incoming service. I.E. If you have a 50 amp service from the power company then they will size your meter to match. Not all panels have a main breaker. Even if you have a 50 amp service you might see several 50 amp breakers in your panel if the wire from them to the point of use is sized to code,then it's ok. It doesn't mean you have more than 50 amps available.

[entity-unknown]

Ahh point taken! I've never had a house that didn't have a main breaker matched to the service during my times of understanding AC. Good to know and always something new to learn

[lazy733]

Different subject same welder!! My welder when turned on (DC) started to make loud hum ,works on a/c not dc did a rectifier short? any help would be appreciated

[MinnesotaDave]

No DC output, and a loud hum like the machine is working hard, are good indications of a bad rectifier.

[entity-unknown]

I'd agree with Dave!