Welder- 240V

[jhelrey]

I believe I can get away with a 30A breaker. I know I could use 10 gauge wire but I think I'd use 8 gauge. Outlet is within 3 feet of main panel.

Thoughts?

 

[alfredeneuman]

Because the Duty Cycle is 25%, you're allowed to cut the amperage requirements by 50%.
(NEC Table 630.31(A)(2) Duty Cycle Multiplication Factors for Resistance Welders)
That 24.8A becomes 12.4A. You could use # 14.

 

[jhelrey]

I'm curious to know why the welder has a 50A plug then...

 

[mike93lx]

I'm curious to know why the welder has a 50A plug then...

Because that is what welders use.

I would run a minimum of 12, but tend to go to 10 just as it's minimal added cost on a short run and it's enough to not really need to worry much about duty cycle on a future upgrade

 

[jhelrey]

So I'm correct in my thinking of 30A breaker with either 10 or 8 Gauge wiring?

 

[mike93lx]

Sure, send it.

 

[nadogail]

That 30 Amp breaker and 10 or 8 gauge should meet the minimum requirements; what about future growth?

 

[G-ManBart]

Because the Duty Cycle is 25%, you're allowed to cut the amperage requirements by 50%.
(NEC Table 630.31(A)(2) Duty Cycle Multiplication Factors for Resistance Welders)
That 24.8A becomes 12.4A. You could use # 14.

That's not really true. The amperage requirements are whatever the machine requires. The conductor and breaker sizing are what change, but only if it's a dedicated outlet for a non-continuous load, and marked as such (depending who you want to listen to).

 

[G-ManBart]

So I'm correct in my thinking of 30A breaker with either 10 or 8 Gauge wiring?

Yes...a 30A breaker and 10ga wiring would be fine. 8ga isn't necessary, but would give you room if you get a bigger machine later and then it would just be a breaker swap. One of my welder outlets is 230V/50A and that's what happened....started out as a 30A breaker with 8ga wire (THHN going off memory) and then I got a bigger machine so I swapped to a 50A breaker.

 

[Walkers]

So I'm correct in my thinking of 30A breaker with either 10 or 8 Gauge wiring?

With only 3 feet of wire your decision is not all that critical.

 

[alfredeneuman]

The conductor and breaker sizing are what change, but only if it's a dedicated outlet for a non-continuous load, and marked as such.

There is no such requirement.

 

[gmcgeo]

I have 8g with 30amp breaker

 

[mike93lx]

I have 8g with 30amp breaker

Why? Just curious

We can all do what we want when it's in excess of code, but short of having some leftover wire kicking around, that's a puzzling combo

 

[gmcgeo]

Why? Just curious

We can all do what we want when it's in excess of code, but short of having some leftover wire kicking around, that's a puzzling combo

I had the wire, and was also running 50' so i just used what i had.

 

[mike93lx]

I had the wire, and was also running 50' so i just used what i had.

I think that's an important distinction.

Someone looking to do this that doesn't have the wire on hand is wasting money buying #8

 

[rooster59]

Nice thing is the 3 feet from main panel. Cost of 6 gauge with a 50 amp breaker isn’t much more than 10g 30 amp breaker that close to the panel. Welders have some goofy code exceptions as to wire size, but that might be based on a stick welder. A modern 250 amp MIG or TIG machine might have a different duty cycle than the code expected. Somewhere in the welder’s manual might chart out the min wire size needed for that machine.

 

[mike93lx]

Nice thing is the 3 feet from main panel. Cost of 6 gauge with a 50 amp breaker isn’t much more than 10g 30 amp breaker that close to the panel. Welders have some goofy code exceptions as to wire size, but that might be based on a stick welder. A modern 250 amp MIG or TIG machine might have a different duty cycle than the code expected. Somewhere in the welder’s manual might chart out the min wire size needed for that machine.

The code isn't based on stick welders. It's based on duty cycle, which doesn't care what process you are using.

Wire your welder with #6 and a 50a. No one and nothing will get hurt in the process except your wallet

 

[gmcgeo]

I think that's an important distinction.

Someone looking to do this that doesn't have the wire on hand is wasting money buying #8

yeah, you are right. i should have put the important info

 

[TractorJeff]

I would use the 6ga on 50a and never worry who will come along and plug something else in there!
After all you may move or die, then someone else will own it. You don't know what they will plug in it!!

 

[ycgoat]

If at my place and I was running a cable concealed in the wall, where it would be difficult to change later I would consider a larger wire for future upgardes

 

[G-ManBart]

There is no such requirement.

People argue over this all the time...some see it one way, others see it the other way. 630.13 and 630.14 are the two applicable sections. If the outlet is marked, you can't be wrong, but everybody can decide for themselves.

From a practical perspective, I can't imagine running a circuit with undersized conductors and not marking it clearly.

 

[wyliesdiesels]

That's not really true. The amperage requirements are whatever the machine requires. The conductor and breaker sizing are what change, but only if it's a dedicated outlet for a non-continuous load, and marked as such.

what code requires the outlet to be marked?

 

[wyliesdiesels]

I would use the 6ga on 50a and never worry who will come along and plug something else in there!
After all you may move or die, then someone else will own it. You don't know what they will plug in it!!

except why should we worry about what someone else does down the road? thats a fools errand. not our problem what someone else may or may not do down the road.

if we did that for every aspect of construction we would have crazy never ending projects.

What if someone adds a second story on down the road? oh we better increase the joist sizes now.... smh

 

[wyliesdiesels]

People argue over this all the time...some see it one way, others see it the other way. 630.13 and 630.14 are the two applicable sections. If the outlet is marked, you can't be wrong, but everybody can decide for themselves.

From a practical perspective, I can't imagine running a circuit with undersized conductors and not marking it clearly.

twisting code to suit your narrative?

630.13 is for disconnecting means and says it needs to be labeled. the disconnecting means is to be a switch OR BREAKER. so the breaker gets labeled. This isnt the code that you claimed required marking of the receptacle.

630.14 is for welder rating plates and says absolutely nothing about marking the receptacle for welder use only like you claimed.

Why do you make up things about code?

 

[alfredeneuman]

630.13 and 630.14 are the two applicable sections.

630.13 Applies to disconnects not integral to the machine, not outlets.
("The disconnecting means shall be a switch or circuit breaker,")
630.14 Applies to the nameplate on the welder itself.
Edit: Oops, Wylie beat me to it by almost an hour

 

[corn chip]

there wasnt a 220 outlet in my garage when i bought my welders but my neighbor at the time happened to be a electrician so he put a outlet directly below the main panel and gave me free about 20' of 6awg with male and female ends basically as a extension cord to run from the main outlet to the middle of the garage. seems like the breaker is 30a

 

[quickfarms]

8 gauge copper is good for 50 amps

I have run all my 220/240 circuits in 8 gauge and then I put a breaker sized to the load or plug

 

[mike93lx]

8 gauge copper is good for 50 amps

I have run all my 220/240 circuits in 8 gauge and then I put a breaker sized to the load or plug

8 nm-b is only rated for 40a. You need to use thhn/xhhw to get a 50a rating.

And in a Continuous load, like a car charger, that rating is 32a. This is the problem with arbitrarily sizing electrical wiring. You can just as easily undersize as you can waste money. And copper isn't cheap

But that is beside the point as welders are different

 

[G-ManBart]

twisting code to suit your narrative?

630.13 is for disconnecting means and says it needs to be labeled. the disconnecting means is to be a switch OR BREAKER. so the breaker gets labeled. This isnt the code that you claimed required marking of the receptacle.

630.14 is for welder rating plates and says absolutely nothing about marking the receptacle for welder use only like you claimed.

Why do you make up things about code?

I'm not twisting anything. Like I said above, go to any electrical or welding forum and people will argue this topic to death. It always seems to revolve around 630.13 and .14 so that's what I mentioned. I was pointing to the parts people argue about. If you want to debate it, that's fine....I'm not going to do that.

I mark any circuit with undersized conductors since it simply can't hurt.

 

[G-ManBart]

630.13 Applies to disconnects not integral to the machine, not outlets.
("The disconnecting means shall be a switch or circuit breaker,")
630.14 Applies to the nameplate on the welder itself.
Edit: Oops, Wylie beat me to it by almost an hour

Just for you I went back and made an edit to the post where I corrected your blatantly inaccurate comment about reducing amperage requirements to add a qualifier about marking outlets

 

[wyliesdiesels]

I'm not twisting anything. Like I said above, go to any electrical or welding forum and people will argue this topic to death. It always seems to revolve around 630.13 and .14 so that's what I mentioned. I was pointing to the parts people argue about. If you want to debate it, that's fine....I'm not going to do that.

I mark any circuit with undersized conductors since it simply can't hurt.

not sure what there is to argue about when it comes to the supposed requirement of labeling a receptacle. no where in there does it say that. maybe theyre referring to the urban legend code book??

 

[alfredeneuman]

Like I said above, go to any electrical or welding forum and people will argue this topic to death.

Could you point out a few? I'm a member of 4 different electrical forums & lurk at 1 welding forum.
I've seen the subject come up only once (twice if you count this time)

 

[Aaron_W]

except why should we worry about what someone else does down the road? thats a fools errand. not our problem what someone else may or may not do down the road.

if we did that for every aspect of construction we would have crazy never ending projects.

What if someone adds a second story on down the road? oh we better increase the joist sizes now.... smh

I understand the what if argument because lawyers will twist anything.

I'm not an electrician and I didn't sleep at a Holiday Inn express last night but I agree with you. Ultimately down the road it is that future persons responsibility to look at the breaker. If they put a 50 amp draw on a 30 amp circuit just because the plug fits, or worse upgrade the breaker to 50A on wire rated for 30A because they keep popping the 30A breaker then they are not doing their due diligence.

As long as it meets current code I don't see how future idiot has a leg to stand on.

 

[Norcal]

Too many people read the Urban Legend Code, the problem is it is printed on soiled bathroom tissue.

 

[dcg9381]

I'm curious to know why the welder has a 50A plug then...

My welders have 50A plugs because I set up all 240V outlets to have that plug. My breakers are set to the appropriate size for the conductors.. Just a guess.

 

[Aroberson77]

I run a 50 amp breaker and 6 GA wire for my welder and am currently wiring a 40 amp with 8 GA wire for my air compressor. The idea is I could also run a smaller welder on the 40 amp circuit if I am doing sheet metal mig work. Both outlets will have 50 amp plugs.

 

[mike93lx]

I run a 50 amp breaker and 6 GA wire for my welder and am currently wiring a 40 amp with 8 GA wire for my air compressor. The idea is I could also run a smaller welder on the 40 amp circuit if I am doing sheet metal mig work. Both outlets will have 50 amp plugs.

Wiring for a compressor is a different animal than a welder, just to reiterate what's been said here.

Running a welder on the 40a circuit with #8 is almost certainly not a problem, but if you sized the welder circuit's wire to align with what code allows, you would not be able to run a big compressor on it.

Also me careful with that compressor on a plug. Plugs need to be rated for the HP of the motor and a regular 50a plug is only rated for up to 3hp

 

[wyliesdiesels]

I run a 50 amp breaker and 6 GA wire for my welder and am currently wiring a 40 amp with 8 GA wire for my air compressor. The idea is I could also run a smaller welder on the 40 amp circuit if I am doing sheet metal mig work. Both outlets will have 50 amp plugs.

you really cant compare the 2.

what is the HP rating on the compressor motor?

If youre running #8 for it its most likely over 3HP and thus standard nema plugs and receptacles will not work. it will need to be hardwired.

 

[jhelrey]

Well, electricians had some excess gauge 8 THHN wire from a project so that will be used...

 

[alfredeneuman]

it will need to be hardwired.

.... or a prohibitively high $ pin and sleeve plug and receptacle will need to be used