I just noticed the bay of the shop that I have renting for storage is already wired from when it used to be a limousine fab shop. I remember that they used to have a high-powered MIG welder in one of the bays but I can't remember how powerful it was.

The plug reads as follows:

NEMA 6 - 50 R
50 A. - 250 V.
LEVITON


And the breaker box has the following:

Mains Rating 225 Amps


The lowest breaker has 30 on it and the highest has 60.

Is there a way to test to see if I'm actually getting 50 amp service at the receptacle in my bay? Is the rating on the receptacle actually the max rating for a MIG welder? It seems higher than I would have expected for this little shop but maybe I'm just really lucky since I dont pay for the electric I use there.

Remove the panel cover and check to see which 2-pole breaker the receptical is attached to.

(I misread it and thought you wanted to know the primary amperage capacity coming into the box).

A 30 amp breaker (220V) does great for my Lincoln 255. Typically a TIG will require 60 amps. The plug is fine for a MIG.

What size is your welder?

edit: misread the ?

I have been using an older Lincoln stick welder at my old shop, but there isn't any room for me there any more, so i'm gonna buy a welder for the new shop. I don't want to re-wire this shop since I'm just renting it, but I would like the most powerful welder it can handle. I'm sick of wimpy 110 MIGs but like the cleaner beads and not having to change rods constantly is a good thing.

That NEMA rating indicates that the recptacle is rated for 50amps @ 250v, it will hold up fine as long as the breaker is sized to the wire i.e. 2pole 50amp breaker should be at least a #8 wire any less and the wire will be subject to burning up before the breaker trips. ;) That concludes our lesson on electricity for today:flipoff2:

well? If you really wanna know.. just look up the breaker # on the chart inside the panel. At least.. sometimes there is a chart filled out isnide the panel.

Otherwise plug something in to it and start turning the breakers off one by one till you get to yours. Then at least you know what size breaker was attached to that outlet. If it's a 50A breaker, a 50A outlet.. I'de feel fairly safe plugging a 50A load in since a licensed electrician more than likely did the install of the electrical.