Adding 220v welding circuit to the shop/garage

[nickel plate]

I want to take a welding class at our local community college but while I'm waiting to sign up, I need to look into installing a 220v receptacle in my shop. I have an approximately seven year old G.E. Powermark Gold sub panel (wired from the house panel) just inside the man door, there are 3-20amp and 1-15amp breakers installed with room for eight more breakers. I can't find anywhere written what the panel's rating is. Before I obligate an electritian to quote the job, I thought I should ask the group's opinions/suggestions.
From a welding safety standpoint, should the receptacle be mounted inside or outside the shop?

 

[Brico]

Mount that welder plug inside your shop, no reason in making it a NEMA 3R installation. Thats electrical term for weather rated devices and covers.
No advantage to outdoor becuse you can make or puchase a long enough cord to go where ever, mounting inside close to your roll up not a bad location. Another thing to consider is running one conduit larger enough to put a small sub panel in your shop for future

 

[Baby Grand]

If your plug is inside, you will be tempted to do welding inside.
Depending on the type of welding you do, you may want to get a few fire extinguishers and salt the shop with them. Maybe mount one to your welding cart.

Make a quick inventory of the space:
1) Is your shop attached to your house?
2) Is your shop made of combustible materials?
3) Do you store gas/fuel in the shop?
4) Do you have adequate ventilation?

Those pesky sparks can roll forever and will find old papers or anything else combustible under cabinets and tools clear across the building.

Work safely and you will be deeply satisfied with the freedom & value your new skills will represent. Good luck in the class - it's a great way to get started.

-Jim

 

[LD1]

Boy, the saftey police kind grilled you right away:confused2:

I wont do that, since you are taking a class, I'll assume they cover some saftey there.

As to your question, definatally inside. And usually close to the breaker panel. Reserve the longer cord and mobility for the welder itself.

No to your electrical questions. From the description, it does sound like a 100A 220v panel.

The rating of the panel will be whatever the main breaker is at the top. If you are not comfortable working on these things, then by all means, hire an electrician. But it sounds like all you need is a 40 or 50A breaker (depends on what welder you get) made for your box. Kill the main breaker at the top, Snap in the breaker, and then wire up the plug.

There are several 40-50A style 220v plugs. In my shop, I chose a 50A range style plug. Whatever you do choose, make sure the welder plug is the same. So you may want to wait until you have the welder first. Once you see what plug it has, drop some 6ga or 8ga wire off the breaker and wire you a new pluc up:thumbsup:

 

[ssmith general]

I've done this a couple of times. Buy the wire and receptical at home depot and run a dedicated wire from where you want it to the vicinity of your breaker panel. Then hire an electrician to hook it all up right. You will save tons by buying the wire and receptical yourself and running the wire yourself. But it's not worth saving on the install. Have an electrician do it. It will only take him maybe a half an hour. You'll pay the minimum probably.

 

[SixHoeBob]

What size breaker at the house is feeding the shop sub panel? 120v or 240V? How far from the house panel to the shop panel?

 

[Transit]

Yes, it could be a 100 amp panel and should have a mane barker. I would also locate where and how it is connected back to your house panel and see what gauge wire is used for that run just to be on the safe side.

 

[nickel plate]

If your plug is inside, you will be tempted to do welding inside.
Depending on the type of welding you do, you may want to get a few fire extinguishers and salt the shop with them. Maybe mount one to your welding cart.

Make a quick inventory of the space:
1) Is your shop attached to your house?
2) Is your shop made of combustible materials?
3) Do you store gas/fuel in the shop?
4) Do you have adequate ventilation?

Those pesky sparks can roll forever and will find old papers or anything else combustible under cabinets and tools clear across the building.

Work safely and you will be deeply satisfied with the freedom & value your new skills will represent. Good luck in the class - it's a great way to get started.

-Jim

1) NO
2) YES
3) YES
4) YES

Thanks, Jim

 

[nickel plate]

What size breaker at the house is feeding the shop sub panel? 120v or 240V? How far from the house panel to the shop panel?

The breaker at the house that feeds the shop is a 2 pole type MP-T 120/240v.
We followed the NEC wire size code-the house panel is about 75 feet from the shop sub panel and is in an underground conduit.

 

[bky]

Yes, it could be a 100 amp panel and should have a mane barker. I would also locate where and how it is connected back to your house panel and see what gauge wire is used for that run just to be on the safe side.

I would also agree it is a 100 amp rated panel. The only way to tell is on the sticker on the door to the panel, there will be a label that states the ratting. there may not be a main in that panel since it is fed off the house panel. See what size breaker that is in your main panel. and that will determine if you have adequate wire feeding the main lug sub panel.

 

[LD1]

The breaker at the house that feeds the shop is a 2 pole type MP-T 120/240v.
We followed the NEC wire size code-the house panel is about 75 feet from the shop sub panel and is in an underground conduit.

Obviously its a 220v breaker:confused2: But how many amps is it???

And the second part of the statement implys that YOU ran the wire to the shop???

What guage did you use? How many amps did you size it for?

 

[hr3]

MP-T 120/240v

... But what size ??? 60 70 80 90 100.. It should be stamped on the handle..??

 

[dstig1]

As most stated, I'd mount it indoors (out of the weather) and use a hefty extension cord to put the welder close to your work. I've seen "welding extension cords" at our local Fleet Farm stores - just a heavy 8ga cord with the common plugs already on them. Or you can make your own. Sounds like you have plenty of space in your subpanel. The real question is not if the subpanel can handle it but if the breaker and wire feeding it from the main panel are large enough. Breakers always have the amp rating stamped on the switch handle. That's the number you need to post here.

 

[nickel plate]

Obviously its a 220v breaker:confused2: But how many amps is it???

And the second part of the statement implys that YOU ran the wire to the shop???

What guage did you use? How many amps did you size it for?

Perhaps all of this is obvious to you-I'm here asking the questions because it isn't obvious to me. On each of the two interlinked toggle levers is stamped 100 amps.

I did not run the wire to the shop-my liscensed electrician did. I double checked his calculations as I was the one who dug the trench, measured the run including the ups and downs in the conduit. I'll climb under the house tomorrow and read the wire spec. Slow down on me-O.K.?

 

[Inspector507]

If you have 100A to the shop and the wire is sized accordingly, you'll have no trouble adding a welder out there.

 

[dstig1]

Yep, you'll be fine. You can verify the wire if you like, but given that an electrician that you hired did it, and you appear satisfied with his work, you should be just fine. Heck, I'm running a 50A welder circuit on a 60A subpanel right now with no issue. I'm guessing he used 4ga or possibly 2 ga Cu for that distance.

 

[SixHoeBob]

100 amp 240v sub-panel, you can use a 50 amp breaker for the welder in the sub-panel. Put the receptacle just inside the door and do all of your welding and grinding outside the shop.

It would be better to do your welding in the cold, than to burn your shop down. If the shop burns not only will you be doing all of your work in the cold, you will have almost no tools to work with.

What is the most cost effective design for building a small welding shop, say 24x 30?

 

[grsthegreat]

check the panel that feeds the shop panel. Make sure there's a 100 amp, 2 pole breaker on that panel also. Just cause the panel label says 100 amp doesn't mean its actually fed with a 100 amp circuit. Ive seen 100 amp panels with 100 amp main breakers fed off of a main panel with a 50 amp breaker and #6 alum wire.

at the least you should have 2 aluminum feeders running from shop to main panel. I doubt they wired it with copper wire due to the costs involved. almost everyone uses aluminum feeders for the sub-panels these days. as long as the ends are lugged down tight, alum is a fine conductor. The powerlines in the street are aluminum. If they are alum it will be stamped 2XHHW or some such.

if both have 100 amp breakers you should be fine. agree that most stick welders use 50 amp, 240

most large migs will also work on this circuit. Some smaller migs only need 30 amp, 240 volt or even110 volt.

im an electrical contractor..been doing this a long time. I agree also with the outlet indoors and a longer extension cord, but that depends on how far the shop panel is from the door.

As far as doing all the welding outdoors goes, ive wired alot of welding shops in my life, and they all weld indoors in the warm air. Just make a welding bench that can be moved towards the center, away from the walls. BUY GOOD FIRE EXTINGUISHERS

I have a portable outside air device that feeds outside air to a face mask. I use this when plasma cutting, welding or painting in the shop. They only cost 100-150 bucks, feed off of a 50 foot long garden type hose, and add alot of safety to breathing fumes.

 

[dstig1]

check the panel that feeds the shop panel. Make sure there's a 100 amp, 2 pole breaker on that panel also.

I believe that was what he said, but it could be interpreted 2 ways, so the OP should confirm what he meant to be clear.

 

[nickel plate]

I believe that was what he said, but it could be interpreted 2 ways, so the OP should confirm what he meant to be clear.

Here is a photo of the main panel and the shop breakers.
I do remember the wire to the subpanel being copper.