Adding 220v welding circuit to the shop/garage

[SixHoeBob]

Experience has shown that when the mineral spirits ignite, the paint brush handles will become charred....

 

[bky]

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

After seeing your picture you have 100 amps feeding the sub panel and would be sufficient to handle the wielder along with the existing circuit. the handle tie on the red Bryant breaker would no longer meet a code requirement.

 

[SixHoeBob]

After seeing your picture you have 100 amps feeding the sub panel and would be sufficient to handle the wielder along with the existing circuit. the handle tie on the red Bryant breaker would no longer meet a code requirement.

Avoid doing any welding for an electrical inspector or your fire insurance agent.

 

[KennyG]

I figured everything would be covered here but I notice there wasn't much discussion on the size of the welder circuit. Most home use welders are going with something like a 180 amp MIG these days, which seems to do almost anything you need. You can run these pretty hard on a 30 amp circuit, which is an economical installation. You will probably need to use a 50 amp plug/outlet, but don't let that confuse you. You can wire that up with no. 10 wiring as long as you have 30 amp breakers.

Lincoln, in particular, is very confusing on what service is required for their welders, but I have a Lincoln 180 on a 30 amp circuit and it has never been a problem. I found a Ebay seller with a real deal on 10/3 SOOW cable (braided, thick flexible insulation) and made a 60 ft. extension cord and life is now good.

 

[lostcause]

I figured everything would be covered here but I notice there wasn't much discussion on the size of the welder circuit. Most home use welders are going with something like a 180 amp MIG these days, which seems to do almost anything you need. You can run these pretty hard on a 30 amp circuit, which is an economical installation. You will probably need to use a 50 amp plug/outlet, but don't let that confuse you. You can wire that up with no. 10 wiring as long as you have 30 amp breakers.

Lincoln, in particular, is very confusing on what service is required for their welders, but I have a Lincoln 180 on a 30 amp circuit and it has never been a problem. I found a Ebay seller with a real deal on 10/3 SOOW cable (braided, thick flexible insulation) and made a 60 ft. extension cord and life is now good.

with a little searching you will even find that it is generally safe and legal (i can't quote on specific laws everywhere) to run a 50a breaker and receptacle with wire smaller than 6/2 for a welder. this can be allowable based on the duty cycle of the welder. it's an area that causes heartburn with many people (especially on forums) but it isn't wrong. it does, however require special circuit labeling for the intended use/duty cycle appliance. this same thing is often done in hvac and cases where there are electric motors with high startup draws, but low continuous draws.

while it is acceptable, i would only use this setup in a situation where smaller wiring was already run and would be very difficult to change, such as through finished walls, or under under concrete/asphalt. if you are running a new circuit, i'd opt for matching the wire/breaker/receptacle sizes. generally speaking, a 50a breaker and receptacle with 6/2 copper will power most any device a homeowner is likely to have. when i did my garage i opted for 6/3 copper and just wire nutted and taped over the neutrals in the boxes. i figured that since i was sheathing over the inside walls, i would do this on the odd chance that some future appliance i bought might require a 120/240 circuit. easier than tearing it all up to rewire later.

 

[grsthegreat]

I figured everything would be covered here but I notice there wasn't much discussion on the size of the welder circuit. Most home use welders are going with something like a 180 amp MIG these days, which seems to do almost anything you need. You can run these pretty hard on a 30 amp circuit, which is an economical installation. You will probably need to use a 50 amp plug/outlet, but don't let that confuse you. You can wire that up with no. 10 wiring as long as you have 30 amp breakers.

Lincoln, in particular, is very confusing on what service is required for their welders, but I have a Lincoln 180 on a 30 amp circuit and it has never been a problem. I found a Ebay seller with a real deal on 10/3 SOOW cable (braided, thick flexible insulation) and made a 60 ft. extension cord and life is now good.

NOPE: you SHOULD NOT wire a 50 amp outlet with #10 for a 30 amp circuit. This gives a future potential problem in that someone else down the line can assume that this 50 amp outlet is set up for a 50 amp circuit, and this causes problems. if you use a 50 amp receptacle, please wire it for 50 amps. better to have more power available than you need.

The NEC does not allow you to do this. it may work, but isnt right.

 

[lostcause]

NOPE: you SHOULD NOT wire a 50 amp outlet with #10 for a 30 amp circuit. This gives a future potential problem in that someone else down the line can assume that this 50 amp outlet is set up for a 50 amp circuit, and this causes problems. if you use a 50 amp receptacle, please wire it for 50 amps. better to have more power available than you need.

The NEC does not allow you to do this. it may work, but isnt right.

i'm thinking that as long as the breaker and wire size match, an overrated receptacle is not an issue? if you plug a larger than allowable device in, it will only trip the breaker. i can't quote the code, but i can't see where there is any safety issue. i would think it would fall into the same category as my above post where i mentioned mismatched breaker/wire sizing. i came across that two (maybe three) years ago when i wired my garage for a welder. maybe something has changed? i agree that these situations are not ideal, but from what i read they are legal, acceptable, and safe, as long as they are done properly.

edit: as i said, i'm not a pro, but i did a lot of research before i did my shop. search for nec article 630 and read up if interested. i figured i'd add this to curb any rule of thumb debates that spawn due to my posts that do not necessarily support, but at the very least add legitimacy to this procedure.

 

[grsthegreat]

i'm thinking that as long as the breaker and wire size match, an overrated receptacle is not an issue? if you plug a larger than allowable device in, it will only trip the breaker. i can't quote the code, but i can't see where there is any safety issue. i would think it would fall into the same category as my above post where i mentioned mismatched breaker/wire sizing. i came across that two (maybe three) years ago when i wired my garage for a welder. maybe something has changed? i agree that these situations are not ideal, but from what i read they are legal, acceptable, and safe, as long as they are done properly.

edit: as i said, i'm not a pro, but i did a lot of research before i did my shop. search for nec article 630 and read up if interested. i figured i'd add this to curb any rule of thumb debates that spawn due to my posts that do not necessarily support, but at the very least add legitimacy to this procedure.

This got me thinking...where in the code book is this listed. Its come up a few times over the years, and we have had to rate the cord, wires, breakers and plugs for the device.

I got out the code book (something i hate to do) and began perusing the 800+ pages. Heck if i can find it.

So i called one of my inspectors, and hes not even sure where its in the book, but he told me that to be legal, a welder needs a MOLDED case cord plug rated for the equipment. The wires feeding the plug AND the breaker have to be rated to match the receptacle. However, welding circuits can be rated up to 200% of listed capacity to allow for startup.

So a welder rated at 30 amps is usually fed from a 50 amp circuit. The cordset attached to the welder will be over-sized and IF it has a 50 amp plug and it HAS to be fed with a 50 amp circuit.

Hes going to see if he can find the actual code, but told me its Monday.....too early for him to look. he'll get back to me.


UPDATE:

Article 210.21(B)(3) Table

Receptacle Ratings for Various size circuits

the table is included here. He further tells me that some inspectors allow the 30 amp circuit using a 50 amp recepticle, but he doesnt allow it. so i guess its ok as long as your not cought.

 

[LD1]

i'm thinking that as long as the breaker and wire size match, an overrated receptacle is not an issue?

I am not a pro either but I agree with this.

You see 20A 120v recepticles wired with 14ga and a 15 amp breaker all the time. Same difference here.

Oversizing the recepticle/plug is not a problem

Oversizing the wire is not a problem

Oversizing the breaker...BIG PROBLEM

 

[grsthegreat]

I am not a pro either but I agree with this.

You see 20A 120v recepticles wired with 14ga and a 15 amp breaker all the time. Same difference here.

Oversizing the recepticle/plug is not a problem

Oversizing the wire is not a problem

Oversizing the breaker...BIG PROBLEM

The code does allow a 20 amp or a 15 amp receptacle wired to a 20 amp circuit in RESIDENTIAL situations only. in commercial it does not allow this.

As you can see in the above PDF chart. Its very specific in the 30 and 50 amp ratings.
Hay, i dont write these **** rules, i only have to follow them

I dont agree with them