My uncle has a separate garage/shop that was built a few years back. Recently the GFI's keep tripping when he starts welding with his tig which is set up on its own 220 circuit. All 110 outlet's are fine until the moment he strikes an arc while welding. What could be causing this?

The 110's that are on one 20 amp circuit. Hardly anything is plugged into any of the outlets so they are not being overloaded.

Electricity scares the bejebbers out of me, saw some stuff when young. Thinking though, maybe it's a internal issue with the welder, not the breakers.

Try switching the 110 outlets to the other side of the 220.

Not sure a GFI is the right thing for a welder I had one on my chicken coop line but the water heater kept popping it and thats way less of a draw

I didn't read this as the welder was set up with a GFI. I thought he was only referring to the 110 recepts being on a GFI.

Adam,

Do you know if he has a second breaker box in the shop? Also, what gauge wire did he run from the main beaker ( in the house), to the shop??

If he has 100 amp service in the shop and has the 220 plug with the proper sized breaker (NOT 20 AMP), it should not trip unless there's a short somewhere! My Miller and 7 hp compressor are each on the own breaker.... I'm thinking 40 amp for the compressor and a 60 for the wire feed, as I'm not down the shop now.

Had a fan/light combo above our range when we built our home.... About 10 years later we installed a combo above stove microwave, fan, light unit. If the wife had a caserolle in the microwave for anytime longer than 8-10 minutes the breaker would trip.

I found out that the the original light/fan unit was on a 15 amp breaker.... Guy at Menards said "Just replace with a 20 amp breaker"!

When I double checked it was wired with 14 gauge wire, which was correct for the 15 amp breaker, but a 20 amp breaker is for 12 gauge wire...... I ran a new 12 gauge wire wire to the unit, with a 20 amp breaker, and zero issues.

Hope this helps you

check all the ground connections

or maybe his welder is putting power to the ground

Could be the main breaker. Does the weiler shut down to?

Loose ground or Neutral in panel

How far away.is the ground rod from the welder 220 outlet.
Might try running a ground rod of the outlet.

X2
Is the shop fed from the panel in the house? Or does it have its own meter base. But sounds like a loose grd or neutral. Under the bar . Tighten all screws. Tha

Thanks everyone. I appreciate it. Keep them coming.

Correct only the 110's are on gfi. The welder is on 220.. the welder stays on after the 110's trips. I'll ask him tomorrow what gauge wire they ran. When he had the garage/ shop built he built it around his welding equipment in mind (welder on own, compressor on its own etc..)

What do you mean Sullivan? I know he does have 110's on the booth sides of the 220 but at counter height for his work benches.

Antelope Montana, not sure but I'll ask.
This shop has its own panel as it sits about 75'+ away from the house.
We'll check the ground and neutrals the next time I go over

You have two 110 legs feeding your panel. I was suggesting switching your receptacles to the other 110 leg.
The loose neutral/ground suggestion is certainly legitimate also

I think the GFCI's are working properly. If a toaster is plugged into a GFCI, the electricity flows out of the receptacle to the toaster on the black, hot wire. It flows through the toaster and then back to the receptacle on the white, neutral wire. Actually, since house electric is alternating current, the flow of electric keeps changing direction but at any moment, the electricity flowing out on one wire should be the same as the electric flowing back on the other wire. If the flow of electricity on the hot and neutral wire isn't balanced, it means electricity is going somewhere it shouldn't - possibly through a person.

A GFCI monitors the flow on the hot and neutral wire. If they are the same, all is good. If they are different, it opens the circuit so nobody gets killed.

When there is a big surge in electric flow (like a welder striking an arc) it causes spikes and dips in the flow of electricity everywhere else. If wires or transformers are undersized, these spikes and dips are more dramatic because the available electricity isn't enough to "fill in" the dips.

What's a capacitor? A capacitor is a device that can store electricity for a very brief time. Inductors can also store electricity. Lots of electrical equipment, including wires, have a little capacitance and a little inductance and can store a little bit of electricity. When there is a big spike or dip in electrical flow on on wire, that stored electricity can continue to flow on the other wire for a very brief time - fractions of seconds. If that happens, you have an imbalance. When you have an imbalance between the neutral and hot wire, a GFCI will trip opening the circuit.

I suspect that the wiring to the main panel is undersized or the transformers at the utility pole is undersized. It's also possible that everything is sized correctly and GFCI's just stink. GFCI breakers are more trouble then they are worth - in my opinion.

If the receptacles are on just one breaker then they are only on one leg of the 220 volt service. You do not have the receptacles divided up between the two legs of the service. What i was suggesting is that you just switch the 110 receptacles to the other leg of the service

Now this right here is so well written, and complete, that I am impressed. Not an easy thing to do! I would also place money that it is correct, and the answer to your problem is contained, there-in.

My first thought is with Yama Cat Loose Neutral

Thanks for the clarification Sullivan.

maintenanceguy, that is a great explanation. Thanks. I am thinking since this is a recent issue it must be a loose wire or the gfi's are bad now.

x2 on a loose ground or neutral they make weird things happen when they get loose also check the ground rod itself corrosion can make them loose ground same with extremely dry dirt