Thread: Shop WELDER. Need Some Electrical Advice

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Heres the Problem.

I got tired of all the little crappy welders and bought a mother of all welders. This is a 320 amp welder that will Mig, Tig, Stick. The problem is when I fire this baby up all the lights in the house flicker. Does any one have any Ideas, short of running a new power line from the street. Like a transformer, or capacitor?


As Always Thanks

I assume this is a 220 volt unit. What is it's current draw (how large a fuse is recommended?). Also, what is the rating of your electrical panel?

A transformer would just change the voltage. No help there. A large capacitor wouldn'e help either. Bottom line. If your power supply to the house isn't large enough, there's nothing you can add to help out - other than more power from the street.

The service from the house to my shop is a 100 amp. The welder is rated at 100 amps at a 60% duty cycle. Sounds like I need to have a 200 amp upgrade in the shop. I was hoping there might have been a better route.

Thanks ART

Just a thought because it happened to me one time...but even though you may be plugged into a 220v outlet, your two 110v sources may be "out of phase".

Now, I'm no electrician...but I learned this the hard way. In other words, you need to make sure the 110v sources are not coming from the same source. One quick way to test this is to take two separate 110v circuits and connect your welder to them.

Where I got into trouble was when I installed a single 220v breaker. Due to the breaker box manufacturer's design, I ended up having to install two 110v breakers and installing them at least two breakers apart.

Again, I'm no electrician so take this for what its worth. If you have a friend who knows this stuff, call him/her and ask them about what I am describing. I scratched my noggin for a couple of hours and then called a good friend of mine and he instantly knew how to fix the problem. I separated the two circuits and it worked like a champ.

but how often are you welding on full power like that?
I would imagine you'd never even be at half of that output.
In which case the welder wouldn't be drawing that much.

Denny W "thats what I meant to say...I just didnt know enough about electricity to teach on the topic." Thanks for jumping in.

b2zone Check for this...I would guess this is your problem!

Good luck!

Get a lot of candles and oil lamps and weld like hell

Check the "Nameplate" label on your welder; it will have at least two ratings listed on it. The "INPUT " voltage should be 220/230 VAC, and there will be an Amperage listed. Then there will be an "OUTPUT " amerage listed at some percent duty cycle; this will be the load available at the welding electrode for that percent of the operating cycle, and may be either an AC, or a DC voltage.

For purposes of determining the size of branch circuit breaker to feed your welder, you are interested in the "INPUT " values. If that is more than 50 or 60Amps at 220/230Volts, then you will need to upgrade your shop main service; you might want to consider doing that, at any rate, just to be on the safe side. You should also connect an "ISOLATING TRANSFORMER " in the circuit that feeds the welder; this will help reduce any interference that the welder will induce in other circuits that are conected to the same transformer that serves the property from the electric company's power pole. Your power company may also require that you have a separate service and transformer to serve a welder that large, just to eliminate this sort of problem. As to the flickering of the lights in the house, this is a normal occurence when a welder is connected to the same service; however, if the lights dim and stay dim as long as the rod is lit, then the transformer serving your house or shop is too small, and the power company should be contacted for advice.

I think you should contact a qualified licensed Electrical Contractor, or a Master Electrician, for the safety of all concerned.

My credentials: Master Electrician, Licensed Electrical Contractor, and 40 year Lineman/Construction Electrician/Millwright (RETIRED).

Nice welder! looks like you already got some good advice but I'll throw in my 2 cents any way. I am assumeing that you bought a single phase welder because of the 60% duty cycle. 100 amps of power should be plenty. most home welders require about 50 amps to run correctly. make sure you have a 50 amp outlet with the correct size feed wire. I had my 200 amp welder temperarily hooked to a 30 amp breaker with 10 gauge wire right out of the box and it would kick off on the duty cycle after about 3 minutes of welding. now its hooked to a 50 amp breaker with six gauge wire about eighty feet from the box and I can weld all day with it.
sure does spin the meter though. good luck

Like Tattoo3 said about the feed wire. this is where I was thinking when you were describing your problem. When I run wire especially to a shop I always step the wire size up at least one gauge. Obviously we don't know the history of your shop or wiring, but possibly someone in the past might have just installed larger breakers to get more power without upgrading the wire. just something else to check. Also check the incoming wiring from the power company. If your living in an older house you may have older smaller wiring coming into your service panel.

whatever you do, you need to get this resolved that surging is not good on the transformer in your welder. I can imagine you probably spent big bucks for such a nice welder, I would hate for you to only get a couple years of use out of it due to "dirty" power.

check the voltage at your welder with the welder off, with the welder on, and with the welder welding. If you have more than a 10% voltage drop, then you need to upgrade something. Most probably heavier wire to the shop, and heavier wire from the shop breaker box to the outlet. As you mentioned, you may even need a heavier drop from the pole to the house. Assuming you are working in a separate building... as you are referring to the lights dimming in the house as you weld, you might be working in your garage?

One other solution, but it might be a bit drastic: Cut off all the house circuits before you run the welder. The wife won't like it.