Right now I am running my MIG welder off my 40 amp dryer circuit which is the opposite end of the house from the garage.
I am thinking on disconnecting the AC line and temporarily attaching a plug so I can use my MIG welder during the winter. The AC is next to the garage. It’s only a 30 amp circuit and my welder calls for a 40 amp. What minimum wire size should I make sure the AC is on to be safe?
I will only be doing some light sheet metal work and will not be running the MIG at full tilt.
Edited 9/30/2008 2:34 pm ET by Senna
Replies
What does the manual for the welder say it needs?
If you're welding sheet metal you don't need a 220 40A feed. I'd do it at 30 and not blink an eye.
The problem is, on an AC circuit the 30A breaker may not be sufficient to protect the wiring from overload, since the setup depends on the overload protection in the AC unit itself.
Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
Won't the circuit breaker just pop if it's overloaded? Are AC circuits undersized?
Edited 9/30/2008 5:18 pm ET by Senna
Like I said, the overload sensor in the AC itself protects the wiring from overload. The breaker just protects against a dead short. Two different things. (I was unaware of this until Bill explained it some time back.)You need to find out the wire size of the AC circuit and determine it's max amperage capacity.
Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
It only works on a dryer circut cuz dryers make hot like a welder, on an AC circut that makes cold, the welder wont run at all.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
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Doh!!
Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
I had a good look at the box again and see two problems. The wire size looks too small looks like 12 guage and I see a hot, neutral and ground - not the correct configuration for the welder.Thanks guys for you help.
If it's a 240V AC it should be hot/hot/ground. They may have used black/white wire instead of black/red, but if it's 240V (double breaker in the panel) then you gotta have two hots.
Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
And they should have remarked the white with. Typically with tape or a marker, but that is often not done..
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
True.
Corporation: n. An ingenious device for obtaining individual profit without individual responsibility. --Ambrose Bierce
"It only works on a dryer circut cuz dryers make hot like a welder, on an AC circut that makes cold, the welder wont run at all."Can't he plug into the AC circuit to remove old welds?
BruceT
Edited 9/30/2008 8:38 pm by brucet9
If he doesn't get freeze dried first.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
http://www.youtube.com/watch?v=Dj_oEx4-Mc4
The world of people goes up and
down and people go up and down with
their world; warriors have no business
following the ups and downs of their
fellow men.
You get a pretty big break on wire size when using welders, particularly one with a short duty cycle. I wouldn't worry too much about it but I would still pull in another circuit.
I have been running a 230a buzz box on a 30a circuit for almost 40 years. I originally used the dryer circuit like the OP, cutting off the welder plug and putting on a dryer plug.
Now I have "dryer" outlets on a dedicated 30a circuit in several places in my garage and one outside for my welder or my 5HP pressure washer.