220v Welding Outlets

[bad_idea]

It's that time! I'm excited. Electrical is ran into my 30x40 building, ready to run some 220 outlets for the welding machines. I ran the electrical into the building myself and it passed inspection, I am fairly competent. Service to the building is a 90 amp breaker in the main panel to a 100 amp panel in the garage.

I have a Hobart Handler 187 (185 amp MIG) and a Miller Thunderbolt (150 amp DC, 225 amp AC Stick) currently. Would like to add a plasma cutter to the collection one day as well as a good TIG welder. I will be the only person working in the garage. I would like 4 outlets on the same circuit around the building. These outlets will be dedicated for welding machine use, will run separate circuits for heaters, air compressor, etc. I understand the NEC allows the circuits for welding equipment to be undersized wire due to the intermittent use of a welding machine. I just can't comprehend the NEC well enough to size the cable properly. I ran the electrical into the building myself and it passed inspection, I am fairly competent.

So, long story short - what is the appropriate NM-B cable size and breaker size to run for a welding machine circuit? I have ran my machines off of a 30 Amp dryer outlet for years and only tripped the breaker once (was doing heavy, continuos welding). I am not looking to go overkill, I would like to install appropriately sized inexpensive cable. I am running a total of 75' of cable and do not want to waste money on this. Thanks for the help all.

 

[bad_idea]

Doing a bit of research, I think I have this figured out.

Hobart Handler 187 Specs - 20.5 Amp Draw
Miller Thunderbolt Specs - 47.5 Amp draw at 20% Duty Cycle - 21.375 Amp Draw
Hobart Airfare 40i Plasma Cutter Specs (Do not own yet, but seems good example)- 40 Amp draw at 50% Duty Cycle - 28.4 Amp Draw
Most TIG welders I looked at with similar capabilities to my current machines look to draw no more than 30 Amps.

SO, with above ratings a 10/2 NM-B is good for 30 Amps and will cover most any machines I ever buy. My research correct? Recommendations? Thanks all.

 

[sr71]

if you're like me and will only use one welder at a time (home use) I ran two separate circuits from garage subpanel
- 40A circuit with 8 gage
- 30A circuit with 10 gage

normally my 40A circuit is used for the air compressor (7.5HP) but as needed I also use it for my arc welder

also ran a 120V x 20A circuits (in series )....for other uses ... cabinet saw, etc.

wait for the electrical guru's to chime in ... I'm just a hack

 

[mike93lx]

Welders have a code exception due to duty cycle. You can run a 50a breaker and outlet with as small as 12 gauge.

I ran 10 thhn with a 50a breaker. Makes it for Welding use only, but it is safe and code compliant.

 

[mm08822]

Welders have a code exception due to duty cycle. You can run a 50a breaker and outlet with as small as 12 gauge.

I ran 10 thhn with a 50a breaker. Makes it for Welding use only, but it is safe and code compliant.

10's protected by a 50A cb is ok.

12's protected by a 50A cb is not ok.

The ocp limit is 200% max of the wire ampacity.

 

[sberry]

Also, cant undersized the wire on circuits with multiple outlets. It is for dedicated outlet circuits. The minimums are for single circuit in pipe, for cable it needs to be one size bigger.
Are you going to have outlets all over? I might add a convenience circuit but usually put them in a "home" and in a garage that size a cord isn't a bad option.
In theory can put a 6 and tap 2 10's to it, if the breaker is 30 could put multiples with 10 wire. But you can't create a situation where a combination from multiple outlets can overload the wire. I might even buy 8 on multiple?

 

[sberry]

It's not really a 21A draw for the Tbolt, at that max it's 48,,, is only running 20%, that is a calculator number for sizing wire. 10 cable and 50 is good for all the machines that come 50 plug and cord except 250 migs. You can use them on it but at spec [ which is very uncommon in a small garage] they require larger wire. 035/c25 won't overload it and if a guy tried other stuff would melt most factory guns off before heating the wire.
I just wire one with 2 outlets and 12 in MC but,,, both wires land on the breaker, not a daisy chain. 12 single circuit in pipe can be 50 but it's not all that great idea and partly due to the connections, 10 is so much sturdier and at 50 v drop is moot for a buzzer. Quite a bit on 12, doesn't make it unsafe but it hurts performance a little.

 

[OccupantRJ]

I am a big believer in infrastructure and possible expansion. I presently have two welder receptacles that I ran the heavy guage wire to feed. I installed a pvc junction box in the attic, then two power runs to the receptacles. I used split bolts to splice in the J box. If I want to add more outlets, I will run them and splice into the J box. This allows me to move welders as needed and still have the amperage capacity.

 

[sberry]

It's not really a 21A draw for the Tbolt, at that max it's 48,,, is only running 20%, that is a calculator number for sizing wire. 10 cable and 50 is good for all the machines that come 50 plug and cord except 250 migs. You can use them on it but at spec [ which is very uncommon in a small garage] they require larger wire. 035/c25 won't overload it and if a guy tried other stuff would melt most factory guns off before heating the wire.
I just wire one with 2 outlets and 12 in MC but,,, both wires land on the breaker, not a daisy chain. 12 single circuit in pipe can be 50 but it's not all that great idea and partly due to the connections, 10 is so much sturdier and at 50 v drop is moot for a buzzer. Quite a bit on 12, doesn't make it unsafe but it hurts performance a little.

 

[mike93lx]

10's protected by a 50A cb is ok.

12's protected by a 50A cb is not ok.

The ocp limit is 200% max of the wire ampacity.

OK, I thought 12 in conduit was OK, but noted, thanks.

Either way, as noted below, 12 is small for a 6-50r anyway.

Annoying that the manufacturer can use smaller wire for the cord than has to be used for the circuit but such is life

 

[sberry]

The real world math is a bit different and not linear. The 50A machines draw close to 40 than 50 and are rarely used wide open, occasionally over duty a bit and not normally at the 104 rated ambient temperature. Many were designed at 220v, now we got 240 and higher which can make up to 4A diggerence. Little dc buzzer is 38/40 with 1/8 jo hy.

 

[sberry]

OK, I thought 12 in conduit was OK, but noted, thanks.

Either way, as noted below, 12 is small for a 6-50r anyway.

Annoying that the manufacturer can use smaller wire for the cord than has to be used for the circuit but such is life

It is listed 12, single circuit in pipe at 80 ft. But, dozen volts drop, small terminations. Going to 10 has 1/4 the drop. None of it a real issue with small electrodes and limited use. I know a master spark got 25 ft of wire and 25 cord 12,,, but he runs a rod once in a while and it's off 99.999% of the time, know another could have any wire for free has the same 10 cable he hooked 30 plus years ago, same deal, an occasional rod, rare even 2 in a row. The 5 ft whip cord doesn't hurt much. 50 ft be a slightly different matter,,, maybe.

 

[sberry]

The new little welders are listed 14 but need breaker reduced to 30 and would should need pigtails to meet the device listing for wire size. They do run well from 12, as I mentioned earlier ran one recent. Machines called 14 at 48 ft, I used 12 at 50. Guy has a 175 mig and a new 200 Synch which is even less.

 

[alfredeneuman]

12's protected by a 50A cb is not ok.
The ocp limit is 200% max of the wire ampacity.

The rating of #12 (EDIT: THWN/THHN) in the 75° column is 25A.
Why is it not OK?
Is it different for welders than it is for motors and AC circuits?

 

[mm08822]

OK, I thought 12 in conduit was OK, but noted, thanks.

Either way, as noted below, 12 is small for a 6-50r anyway.

Annoying that the manufacturer can use smaller wire for the cord than has to be used for the circuit but such is life

The rating of #12 (EDIT: THWN/THHN) in the 75° column is 25A.
Why is it not OK?
Is it different for welders than it is for motors and AC circuits?

I was thinking of NM-B ampacity (20a) when I replied based upon OP's original stated wiring method.

Agreed, #12 THHN/THWN in conduit would be permitted for to use.

 

[ArcticGabe]

Pardon the question, but I'm afraid I don't understand the logic behind the welder exception. If I understand correctly, I could run 12 gauge THHN for a welder and protect it with a 50A breaker, right?

While I hear it may be ok for a welder, what's to prevent the next owner from coming in and plugging in an EV car charger in the same plug once he figures out it is on a 50A breaker?

Seems risky to me. If it's just one circuit, why not just run 8 ga THHN and not worry about it?

Thanks.

 

[Kaizen]

I thought 220 outlets needed to be dedicated? Not four in a circuit?


Sent from my iPhone using The Garage Journal mobile app

 

[sberry]

Pardon the question, but I'm afraid I don't understand the logic behind the welder exception. If I understand correctly, I could run 12 gauge THHN for a welder and protect it with a 50A breaker, right?

While I hear it may be ok for a welder, what's to prevent the next owner from coming in and plugging in an EV car charger in the same plug once he figures out it is on a 50A breaker?

Seems risky to me. If it's just one circuit, why not just run 8 ga THHN and not worry about it?

Thanks.

Because the ev uses a different receptical that requires a different wire size than the welder, uses electric range plug that requires 6 cable, 8 in pipe.

 

[mike93lx]

Pardon the question, but I'm afraid I don't understand the logic behind the welder exception. If I understand correctly, I could run 12 gauge THHN for a welder and protect it with a 50A breaker, right?

While I hear it may be ok for a welder, what's to prevent the next owner from coming in and plugging in an EV car charger in the same plug once he figures out it is on a 50A breaker?

Seems risky to me. If it's just one circuit, why not just run 8 ga THHN and not worry about it?

Thanks.

The outlet should be labeled for welder use only. If you don't have control in your shop of what gets plugged in, then I would agree not to use smaller wire.

With that said, not much else uses a 6-50 plug, so it is almost a mute point

 

[wyliesdiesels]

Pardon the question, but I'm afraid I don't understand the logic behind the welder exception. If I understand correctly, I could run 12 gauge THHN for a welder and protect it with a 50A breaker, right?

While I hear it may be ok for a welder, what's to prevent the next owner from coming in and plugging in an EV car charger in the same plug once he figures out it is on a 50A breaker?

Seems risky to me. If it's just one circuit, why not just run 8 ga THHN and not worry about it?

Thanks.

The logic behind it is that the welder has a limited duty cyclce.

An EV car charger most likely needs a 14-50 and the welder uses a 6-50.

Also, code does not cover what someone MIGHT do in the future.

If it did, the code book would be 3x its current size or more.

I thought 220 outlets needed to be dedicated? Not four in a circuit?

Sent from my iPhone using The Garage Journal mobile app

That depends on if the AHJ uses the international residential building code.

There is no such prohibition in the NEC.

 

[sberry]

The welder code has been 5 here since they invented them. If this was a problem they would have changed it decades ago. The mfg have adapted machines to code vs changing code for machines. That might not be ideal words but somewhat what they do with cord size and features. They make it so it's compliant to run on common 50A welder circuits.

 

[sberry]

I asked fire forensic types at a convention and know a couple of those guys if they ever see fires from compressors or welders. Use of yes, from the equipment,,, never. Number 1 as I recall was heatrrs, used to be holiday lights, toasters maybe. Seems there was some discussion about arc fault in junction boxes but this was late 80's. Before I ever hears of gfci and before afci was even a *********.

 

[bad_idea]

I thought 220 outlets needed to be dedicated? Not four in a circuit?


Sent from my iPhone using The Garage Journal mobile app

I did some research into this. It looks like NEC has no restriction on the number of outlets on a circuit - 110v or 220v. The IBC restricts any circuit over 20 amps to dedicated circuits. My county uses the NEC, so it looks like I am compliant.

 

[alfredeneuman]

There is no voltage such as 110 or 220 in the US or Canada

 

[bad_idea]

There is no voltage such as 110 or 220 in the US or Canada

I'm disappointed in the Garage Journal community, I expected this reply MUCH sooner in the thread.

 

[yatg]

There is no voltage such as 110 or 220 in the US or Canada

220, 221, whatever it takes.

 

[Kaizen]

I did some research into this. It looks like NEC has no restriction on the number of outlets on a circuit - 110v or 220v. The IBC restricts any circuit over 20 amps to dedicated circuits. My county uses the NEC, so it looks like I am compliant.

Does this change when motors are involved? I remember a past thread talking about adding a welder socket off of a 2 post lift circuit and it was said it was not to code?


Sent from my iPhone using Tapatalk

 

[bad_idea]

Apples and oranges. No restriction on outlets, restriction on hardwired items. Please keep in mind I am not an electrician, I've just scoured the inter webs to find requirements as I need to know them.

 

[bad_idea]

220, 221, whatever it takes.

I measured the voltage yesterday (with a Fluke, not a HF cheapie) when I hooked the outlet up at 245 volts and each leg was 122 volts. Where'd the extra volt come from?

 

[yatg]

I measured the voltage yesterday (with a Fluke, not a HF cheapie) when I hooked the outlet up at 245 volts and each leg was 122 volts. Where'd the extra volt come from?

Rounding?
122.3 + 122.4 = 244.7

 

[alfredeneuman]

I measured the voltage yesterday (with a Fluke, not a HF cheapie) when I hooked the outlet up at 245 volts and each leg was 122 volts. Where'd the extra volt come from?

The PoCo's are required to vary no more than + or - 5% of the nominal voltage.
On 240 it's between 228 and 252.
120 is between 114 and 126.

220 and 110 are nowhere close

 

[sberry]

Does this change when motors are involved? I remember a past thread talking about adding a welder socket off of a 2 post lift circuit and it was said it was not to code?


Sent from my iPhone using Tapatalk

I add an outlet to mine. They are not used at the same time and have the same ocpd requirements and I used a 10 on a 30. No chance of overloading it.

 

[alexb2000]

The PoCo's are required to vary no more than + or - 5% of the nominal voltage.
On 240 it's between 228 and 252.
120 is between 114 and 126.

220 and 110 are nowhere close

You know you are "that guy", right?

The kind of person that goes to a BBQ and rattles on and on about how the chicken must be exactly 165 degrees measured with a labratory calibrated thermometer.

We get it, no need to add it to every electrical thread.

 

[sberry]

I had a test done on 100A service. I figured it would sag, it was 100's of ft from the ******, lots connectors, 6 or 8 houses, drop 1 volt with 130 pull on it. As I recall 243 standing, 242 with the pull and the lines not all that big. It 300 ft, maybe more.

 

[sberry]

It should be added to every thread, hasn't been 220 for 60 plus years? My neighbor was doing some stuff, smart guy but I pick on hI'm a little to use the correct term, nothing says amateur like 110/220.

 

[mcbane]

Calling it 110/220 and actually thinking those are the precise voltages are two different things. When I need to pass someone on the highway, I pour the coals to it. Doesnt mean I am unaware that my fuel is actually gasoline rather than coal.

Old timers tend to call it 110/220 and it doesnt mean they are fools.

 

[sberry]

Doesn't mean they are fools but I don't know masters calling it this. Every permit form, all the equipment, the breakers, the outlets say 120, this is true before most of the working men were born or entered the trade.

 

[alfredeneuman]

We get it, no need to add it to every electrical thread.

I think I should use it for my signature.
How does:
"There is no voltage such as 110 or 220 in the US or Canada" / "We get it, no need to add it to every electrical thread" Sound?

Then everyone can enjoy it every time I post

 

[wyliesdiesels]

Doesn't mean they are fools but I don't know masters calling it this. Every permit form, all the equipment, the breakers, the outlets say 120, this is true before most of the working men were born or entered the trade.

Actually motors say 115/200(or 208)/230/460 and some outlets say 125/250v

 

[wyliesdiesels]

Calling it 110/220 and actually thinking those are the precise voltages are two different things. When I need to pass someone on the highway, I pour the coals to it. Doesnt mean I am unaware that my fuel is actually gasoline rather than coal.

Old timers tend to call it 110/220 and it doesnt mean they are fools.

Sure but on a forum geared towards doing work to code, the proper voltages should be called out.

Also, this forum has international members and because many dont list their location, they could very well have 220v service. Youre implying we should just assume they meant 240v. Not a good idea.