The Stovebolt Site Forums The Shop Area The Tool Chest limit amperage; which welder?

I'd like to buy a mig but limited to 50 amp subpanel in my garage. I know, change the main to a bigger panel. Can't do that right now. Is there anything out there that will work short of a portable?

If your just doing work on a car it would proabily work ok

orchidskip,

You might be confusing input voltage requirements with welder output. There are a bazillion welders that would work great on your 50 amp panel. Do some e-shopping and look at the input voltage and current specs.

Stuart

Orchidskip, I'm running an 80 amp mig on 120 volt with a 20 amp breaker, No problems.

Larry

Welder are sold with max AMPS required or Max AMPS out. I have 2 miller Migs on a 200 AMP panell along with other shop tools and never blown breaker. Get er done.

Exellent. Let me modify my question then to which mig for the garage guy (or "guyrage" as I like to call it). I have a stick welder but I'd like clean up some ugly work from PO and do some sheet metal work on my dump bed. 35 years ago I mig welded aluminum cattle trailers with a monster machine.

I run my Hobart 210 amp mig on a 40 amp breaker and it works fine. My house was built in 1974 and still has aluminum wiring. A copper wired 50 amp should run just about any mig. Check the input amperage requirements before purchasing. 50 amp is pretty hefty.

plenty of amps. do you have 220 or just 110.

shouldn't be a problem orchidskip: If you need more than a 50 amp breaker then your talking one monster welder. We have a 300 amp out DC stick welder running on a 40 ampbreaker (at this level it runs down to 40% dutycycle) We also have a 210 amp MIG (at 60% duty cycle) and it is not a problem. If you were running them both at the same time and the air compressor kicked on then you'd have a problem. Just need to limit how many things are running at same time.

You should have plenty of power for a nice mig welder. Unless you want to do large volumes of heavy welding, you should have a lot of good ones to choose from.

John

Wait a sec fellas.

He said 50 amp SUBPANEL, not 50 amp circuit. So if the garage has a couple of 15 amp lighting circuits a 20 amp 110 outlet circuit we already at the limit of the panel and wire going from the house to the garage.

What I think everyone meant is that a 50 amp 220 *dedicated* circuit (ONE 2-pole breaker in the box is marked "50", others are "15", etc., all-togther not exceeding the whole panel's capacity), then you are good to go.

As said, a dedicated 50 amp 220 circuit will power about any welder or plasma cutter a hobbyist can plug into it, but just double-checking that you have that.

As stated, you do need to look at a welder's input amps, not the output (which is always greater). Most of the user's manuals are online and the first couple of pages will give you the wiring requirements.

R-Bo (not an electrician and I didn't even sleep in a Holiday Inn Express last night, but double check this one, I think there is some confusion and we don't want a bolter's stuff burned down)

I am not an electrician but I play one at home.

Most 230v welders require only a 20 amp breaker (note that welders do require a 50 amp rated outlet)

That leaves you 30 amp total for lights and outlets. Plenty assuming you are not running lots of other electrical equipment in the shop. Not enough if you run air cond and heat, stereo, fridge, and then everything else.

All I'm saying is double check, 50 amps is not a lot when you turn on lights, welder, radio, fan, and then the air compressor leaks down and kicks on.

For example, a Millermatic 210 MIG, representative of a couple of the welders referenced in previous posts (and a dang good choice for a MIG machine, by the way)will pull 31.2 amps out of the wall according to the owners manual (page 13) at http://www.millerwelds.com/om/o1325q_mil.pdf

Yes, that is when the welder is turned all the way up, but I wouldn't put it on a 20 amp breaker in *my* shop.

Yes, a Miller 140 amp 110 calls for a 20 amp 110 breaker, http://www.millerwelds.com/om/o225311a_mil.pdf but if you buy a cheap welder they are not as efficient. I had an old crappy flux core 80 amp that called for 30 amp breaker.

Again, I am suggesting original poster ought to add up the amps and read the manual before he plugs things in and pulls the trigger.

I think most states use the same basic electrical code. In Calif the total of the breakers can add up to 165% of the rating of that box. The box itself may not have a main breaker, but it will be running off a 50 amp breaker in the main service panel.
That means all the breakers in that sub-panel can add up to about 80.
Believe it or not, they assume you are not going run everything you own at the same time. Even if you did, that is what the breakers are for.

If you use a millermattic with .035 welding wire(which is Big for sheetmetal) on anysetting above 2 you'll burn thru. I don't think your going to have any problem with putting a 200 amp machine on a 50 amp panell. I run my shop 200 amp (2)machines on 30 amp breakers on setting 4 and some times 5 with .035 wire in high production ornamental iron shop welding 40 and in some cased up to 60%.My panel is rated at 300 amp.Why did I use 30 amp breakers? Can't remember why.

Beaver 53,

I would guess you, or who ever wired the shop, used 30 amp breakers because you wired that circuit with #10 copper wire...that's how circuit protection is sized, on wire ampacity. The circuit breaker protects the wire, not the device.

Stuart

Sorry guys,
I forgot to come back to this posting and check it. I just went out and looked at my subpanel. It's been years since I installed it and I've forgotten what I did. It is indeed 50 amps total. However, it is divided between four 20's and one 30. Shop lights are on a separate circuit. The only thing that COULD run concurrently is the washer/dryer. I guess I must have been using my head that day... I use the 30 amp circuit for either my table saw or my little Lincoln AC/DC 225/125 stick welder as I can only plug in one big draw appliance at a time into the 220 receptacle. So I stand corrected, I'm using two 30 amp breakers for the 220 receptacle. And I think Stuart is right, I used #10 wire for the 220 circuit.

I like the answers here. My favorite word of the day is "ampacity".

Stuart you are right about my oversizing of wire for my outlets in my shop.

You said;
>>It is indeed 50 amps total<<
>>it is divided between four 20's and one 30<<

If you have a 50amp subpanel that is running off a 50amp breaker in the main panel, you should not have breakers that add up to more than 165% of the 50 amps. That's 82.
Four 20's and one 30 adds up to 110amps. No inspector should have ever signed off on that and your insurance co. will tell you sorry charlie, if you should have a fire.

>>I'm using two 30 amp breakers for the 220 receptacle<<
What does that mean?? Depending on the type of breaker, you will either have a larger breaker that stradles both 110v bars with single lever or two breakers rivited together with a bar between both levers so that they flip together.

One more question. Is the neutral bus bar floating in the subpanel???

in your panel you used 10 ga. wire this should be good for 30 amps I have been running a wire panel shop for the last 5 years and that what we allow for 10 ga been wiring since 73 i use a hobart beta mig 170 amp at max (170 amps) it draws 31.6 amps @ 230 volts you should be able to find a good welder that will work with what you have but your panel is overloaded what did you feed panel with if you ran three single wires they should be at least 6 ga for the max load on your panel (82 amps max draw) it sounds like you put the panel in yourself time to fix this is now before you have problems

Thanks guys. None of the 20 amp breakers really do anything. One is for the garage door opener and the other is a circuit that goes out to my barbeque to run the rotierie gizmo and I forget what the other is. None of them are ever doing anything so the risk of overloading is nil.

I've been doing research and will do a separate post for a welder question. Thanks again, Skip