Q.) re: 220v welder plugs

kennyd · Aug 19, 2005

( I have to upgrade my 3 yr old Millermatic 175 mig to something bigger. )

Do I smell a MM210 or MM251 in the air?

I love my MM210, money well spent.

MadReferee · Aug 20, 2005

( Do I smell a MM210 or MM251 in the air?)

At least. When I last upgraded my equipment 3 years ago I thought the MM175 would be all I would ever need. I was having fun doing auto repairs and the occasional larger project.

However, since then my hobby has turned into something more. I am getting more and more non-hobby and non-tractor related requests to build stuff, much of which uses 3/8" and 1/2" steel. So, it's time to go bigger. My MM175 comes with the Miller cart and some consumables. The gas bottle is extra. It's a very nice machine but it's time to move up.

StretchNM · Sep 17, 2005

( If I hook up the 50a plug and receptacle you mention using #6 wire, I realize that covers all the bases on the high side, i.e., will never need anything larger. But if I ultimately end up with, say, a smaller 30a welder, I understand that would require a different receptacle and breaker. But what about wire?

For example, seems I could still leave the bigger wire as long as I swap out the breaker and receptacle appropriately? Or would I have to replace the #6 with #10 for 30a, because the 30a 220v receptacle terminals can't physically accept #6 wire?
)

Dholly,
I'm not an electrician but I've done this before with same problem in 115V. Run a pigtail with a box in the middle. In that box, wire in a 30A circuit breaker. That way, if you're using a big welder on the 50A breaker... then fine. If you're using a smaller welder requiring a 30A, then use your 30A pigtail. If the welder draws more amps than it should, it'll break the 30A in your box... not in your panel.

I think this right...ain't it? For example, I've built 12/3 120V extension cords ending in a 4-outlet box. Underneath the outlets, I'll wire in a 15 or 20A breaker. That way, the circuit breaks right at the 4-way recepticle and not at a pole or fuse box.

Good luck

dixiedrifter · Sep 18, 2005

I just got done wiring up an outbuilding with a welder socket myself.

I used an 8/3 wire from my main fuze box in the house to the out building. It is has two 50 amp fuzes there.

When I got to the building, I simply ran the wires to the socket, and then ran off another set of 8/3 wires to my 125 amp sub panel lug box.

Then I ran off from that two 125 volt (my house current is 125 and 250 volts respectively) circuits and a 30 amp 250 volt circuit.

This should be plenty of power for what I want to use and within the limits of the 8/3 wire.

Farwell · Sep 18, 2005

Dixiedrifter,
Not sure what other folks do but I run #6 wire to any of my 50 amp plugs. If the length of wire gets up around 100 feet I up grade that to #4 wire. Costs more money but it makes me feel more comfortable. The wire that leaves the 50 amp plug to the welder (supplied by the manufacturer) is usually #10 or #8 stranded. On my mig set up, which is 20 amp 120volt, I put in dedicated 20 amp twist lock plugs because all of my other plugs are ground fault protected and I have read that welding units and ground fault circuits don't go together.
I looked all over for a wall plug for my stick welder and finally found a hardware store that had one for around $15. Even spent a week or so looking on Ebay with out any luck.
Farwell

dholly · Sep 26, 2005

Got seriously sidetracked, but back to it now. The #6 wire ($1.66/ft now!), 50a breaker and extra-deep metal quad box are installed and I have the proper receptacle. Connections in the subpanel are done as well. However, I have a question about wiring the receptacle. There are clearly two screw terminals for the black and red hot, plus the third screw terminal which is labled 'Ground". Since I got a ground and a white neutral left, whata goes where? All the neutrals are unbonded from ground in the sub panel box per code. Sorry, no book to refer to, thnx.

jjcc246 · Sep 26, 2005

You should have two power leads, a ground (where the whites are connected in the box) and another ground (where the bare copper wires are connected in the box). The two power leads go on the terminals directly across from each other, the (white ground) goes on the single terminal (middle) and the copper goes to the recepticle. In the panel the two power leads are hooked to the circuit breaker, the white to the common and copper to the ground rod.

Inspector507 · Sep 26, 2005

Use the bare ground wire, that's what it's for. DO NOT connect the white (neutral) to that screw.

Farwell · Sep 26, 2005

Inspector507
I have a question about running wire for a welder.
If I were to run #6 three wire from a 50 amp 220 volt breaker in my main panel to a 50 amp receptacle and in the main panel the red wire goes to one hot leg and the black goes to the other hot leg and the ground wire goes to the main box ground bus that is bonded to the neutral bus by the box bonding screw, what is the problem with wiring the third wire (ground wire) to the neutral bus in this case? This is something I have never been quite clear on. In kitchen stoves they wire this way because there is 120 volt devices in a stove and they use one of the hot legs and the neutral to get the 120 volts.
This thread is going to make me open up my panel to see exactly how I did wire my welder plug because I do not remember.
Farwell

Inspector507 · Sep 26, 2005

Farwell,
 In kitchen stoves they wire this way because there is 120 volt devices in a stove and they use one of the hot legs and the neutral to get the 120 volts 
And they changed that code rule quite a few years ago. Have to use a 4 wire plug now.

 what is the problem with wiring the third wire (ground wire) to the neutral bus in this case? 
I gathered he had a 4 wire system there. Connections in the subpanel 

The welder plug needs an equipment ground and not a grounded conductor.