Welder / Wiring for Small Garage

[alexpops]

Not to highjack the thread, but for the guys that do (have done) this for a living, when calculating distance for voltage drop, is it linear distance from source panel, or do you double that for the length of the circuit?

 

[UncleW]

I’m working on the same problem. I have 100 A service to the barn. I figure I will put in a 50A breaker and run 90C THHN (what Home Depot sells) in 3/4” EMT. IIRC 8 ga is ok for 50A on low duty cycle. I’m guessing that is cheaper than 6 ga Romex. Only question now is whether to run a neutral and bigger wire so I can say “Tesla ready” when I sell the place.

I just wired an outdoor welder outlet as a favor to my neighbor. 50 A breaker, 6 ga THHN in 3/4” EMT w/ liquidtight fittings. But only 3’ from the panel. Stuffing 6 ga wire and the 6-50R recepticle into a standard depth outdoor double gang box=impossible, so I had to get an extra depth outdoor box

 

[Topzide]

8 ga is a 45 amp wire not 50 amp. I run an ac/dc tombstone on a 30 amp circuit with no issues and have done so for 20 years. Put a 40 amp breaker on that 8 ga and call it good.

 

[UncleW]

I was going by the Cerrowire chart.

https://www.cerrowire.com/wp-content/uploads/2021/04/Cerrowire_Ampacity_Chart_210405.pdf

I’d use 6 ga in Romex, but if I’m reading the chart right, I could use 8ga 90C THHN in EMT up to 55 A. Wouldn’t run a continuous load like a Tesla charger off 8ga, though

 

[Gord Baker]

You might consider a 200 Amp service to the Barn.

 

[grsthegreat]

When running 240vac the current load is shared by both hot legs so factor that into your wiring choice. For example if welder pulls 30 amps each leg supplies 15 amps so wiring can be determined by that and wire run length.
wire it and use welder for 240vac and forget about using it with 120vac IMO.

You dont know what your talking about. Each leg carries 30 amp.
nothing like the internet to pass on wrong info.

 

[CliffordK]

You dont know what your talking about. Each leg carries 39 amp.
nothing like the internet to pass on wrong info.

39? Typo?

 

[CliffordK]

I was going by the Cerrowire chart.

https://www.cerrowire.com/wp-content/uploads/2021/04/Cerrowire_Ampacity_Chart_210405.pdf

I’d use 6 ga in Romex, but if I’m reading the chart right, I could use 8ga 90C THHN in EMT up to 55 A. Wouldn’t run a continuous load like a Tesla charger off 8ga, though

It depends on your charging circuit. A Tesla is off in its own world.

My EV (Not a Tesla) uses a basic J1772 connector. At 110V, it pulls about 12 Amps or so, and takes forever to charge.
I should be able to upgrade to 220V at 30A or so which would charge at 4x to 5x the speed of charging at 110V which would be sufficient for my needs.

It shouldn't be a problem charging off of 8AWG.

However, if one is future proofing the circuit, then the more power the better. I'm seeing 48A chargers being common, and some home chargers pulling as much as 80A, 220V. WHEW!!!

 

[MAX-24-Dean]

I was going by the Cerrowire chart.

https://www.cerrowire.com/wp-content/uploads/2021/04/Cerrowire_Ampacity_Chart_210405.pdf

I’d use 6 ga in Romex, but if I’m reading the chart right, I could use 8ga 90C THHN in EMT up to 55 A. Wouldn’t run a continuous load like a Tesla charger off 8ga, though

Copied and pasted from the bottom of the chart in the link.

WARNING! Installation of electrical wire can be hazardous if done improperly, and can result in personal injury or property damage.
For safe wiring practices, consult the National Electrical Code ®, your local building inspector, or a qualified electrician.

#8 THHN is only rated for the ampacity in the 60°C column due to a code requirement in article 110 of the NEC. It would be good for ampacity of up to 40 amps according to the ampacity table in the attachment.
Be safe!

 

[UncleW]

Copied and pasted from the bottom of the chart in the link.

WARNING! Installation of electrical wire can be hazardous if done improperly, and can result in personal injury or property damage.
For safe wiring practices, consult the National Electrical Code ®, your local building inspector, or a qualified electrician.

#8 THHN is only rated for the ampacity in the 60°C column due to a code requirement in article 110 of the NEC. It would be good for ampacity of up to 40 amps according to the ampacity table in the attachment.
Be safe!

Thanks. I have an older copy of the NEC. Be interested in the 60C citation

 

[MAX-24-Dean]

From the 2020 NEC the section you would like to look at in article 110.14.(C) is titled "Temperature Limitations".
Also, along with article 110.14.(1) titled "Equipment Provisions".
You will want to flip between the "Equipment provision" section and the Ampacity Tables at article 310.16 and pay attention to the columns of "temperature ratings for conductors".

 

[UncleW]

From the 2020 NEC the section you would like to look at in article 110.14.(C) is titled "Temperature Limitations".
Also, along with article 110.14.(1) titled "Equipment Provisions".
You will want to flip between the "Equipment provision" section and the Ampacity Tables at article 310.16 and pay attention to the columns of "temperature ratings for conductors".

Thanks! I see where you’re coming from. I always thought “equipment” terminations applied to stuff like pumps, motors, etc. I took that into account when I had to upsize my wire to my irrigation pump due to high ambient temperature and the temperature rating of the terminals on the pump.

So I was thinking that a receptacle that’s 6’ away from a heat source like a welder would be rated on the temperature of the receptacle (=ambient as long as the connections are properly torqued) vs the connection of the power cord to the welder, which would get hot. But hopefully the manufacturer took care of that

I didn’t wade through the whole chart in 310.16, but at least for 8ga wire, it looks the the Cerrowire chart. Not looking at it right now, but I don't think the Cerrowire chart accounted for ambient over 86F. I try to avoid welding any time it’s over 86F, but I’ll ponder that

Interesting stuff. Terminal temperature might explain some of the the code stuff around hard wired EV chargers, cause for sure they’re “equipment” and all that power conversion magic is bound to generate some heat

Thanks again!

 

[grsthegreat]

Unless the termination point has printed 75c rating stamped on it, you have to assume its 60c rated.

 

[UncleW]

Unless the termination point has printed 75c rating stamped on it, you have to assume its 60c rated.

Good point! I looked up the specs on the 6-50 outlet (Leviton IIRC but might have been Hubble) and it was 75C. Other ones from Home Depot, Lowes, Amazon may not be 75C rating so you do have to check! Same with the breaker!

 

[grsthegreat]

The breakers are usually the sticking point in older panels. Heck, even some new breakers arnt rated 75°c.

 

[DaBear3428]

heat dissipation is the issue and the termination lugs have to stand up to the heat transfer as well as the junction between the conductor and the lug. in this case the insulation on the wire is just fine at 75C and will stand up to the current flow but the lug will overheat and become a high resistance point causing more heat to be generated etc. bottom line is a run away event where the end of the conductor loses insulation and the lug becomes unusable leading to a thermal failure.

 

[DaBear3428]

Thanks! I see where you’re coming from. I always thought “equipment” terminations applied to stuff like pumps, motors, etc. I took that into account when I had to upsize my wire to my irrigation pump due to high ambient temperature and the temperature rating of the terminals on the pump.

So I was thinking that a receptacle that’s 6’ away from a heat source like a welder would be rated on the temperature of the receptacle (=ambient as long as the connections are properly torqued) vs the connection of the power cord to the welder, which would get hot. But hopefully the manufacturer took care of that

I didn’t wade through the whole chart in 310.16, but at least for 8ga wire, it looks the the Cerrowire chart. Not looking at it right now, but I don't think the Cerrowire chart accounted for ambient over 86F. I try to avoid welding any time it’s over 86F, but I’ll ponder that

Interesting stuff. Terminal temperature might explain some of the the code stuff around hard wired EV chargers, cause for sure they’re “equipment” and all that power conversion magic is bound to generate some heat

Thanks again!

it is not the welding heat that is the issue it is the resistance of the wire in combination with the thermal insulating/conduction of the insulation. welders are not as big of an issue do to the fact that most do not support 100% duty cycle (duty cycle for a welder is the percentage of time in a 10 min window that the welder can perform at a specific load, most being 60% or less at full load so most circuit breakers are 80% rated leading to some engineering margin.
EV chargers are not subject to this and operated at rated power for hours on end so a 50A EV charger outlet is a lot more serious than a 50 welder outlet

 

[UncleW]

it is not the welding heat that is the issue it is the resistance of the wire in combination with the thermal insulating/conduction of the insulation. welders are not as big of an issue do to the fact that most do not support 100% duty cycle (duty cycle for a welder is the percentage of time in a 10 min window that the welder can perform at a specific load, most being 60% or less at full load so most circuit breakers are 80% rated leading to some engineering margin.
EV chargers are not subject to this and operated at rated power for hours on end so a 50A EV charger outlet is a lot more serious than a 50 welder outlet

This particular Lincoln 50 amp welder has a 20% duty cyle. The instructions below say to use 10 ga wire with a 50 amp breaker. I looked at section 630 of the NEC, and that’s allowed because of the arc welder duty cycle adjustment. Would be a disaster waiting to happen if an EV got plugged into that installation

I ended up putting my welder outlet right next to the panel in the garage. 50amp, 75C or better components & 3 feet 6ga wire. EV code requirements keep changing, but at least it wont melt anything if one gets plugged in

Found an 8 ga extension cord that was cheaper than wiring all the way to the garage door. Will be fine with my particular welder amp draw and duty cycle

 

[5030]

Understand a couple things... The 210 is a transformer machine (I happen to own a pair of them) and they will certainly operate at full output on a 30 amp 220 circuit. The drawback is they are heavy. The advantage of a transformer based machine is a very smooth wire feed arc and excellent wet out. In fact, both of mine are excellent machines and I run them hard in a semi production environment.

Having said that, there are better and less expensive choices out there today. Would I sell mine? Not a chance but if I was in the market for a new MIG welder, I wouldn't buy them in as much as there are better choices out there today.

The multi process welder is an IGBT inverter machine, you can tell that by it's weight. IGBT inverters eliminate the heavy transformer and are much more electrically efficient but that comes at a price and that is, running in MIG, they won't be as user friendly concerning wet out and arc stability when running in MIG mode.

I also see the multi process welder don't come with a foot pedal, you need that to run TIG and neither of them have what I consider a good gas regulator. I much prefer a ball type regulator where you can actually see the gas flow over a needle gage and neither of them are 'fan on demand' which today is basically an industry standard. The issue with any machine where the cooling fan runs constantly is dirt getting sucked in by the cooling fan and getting deposited inside the cabinet and eventually causing issues. I take t he covers off both my Hobarts and blow them out inside regularly. What I did to mitigate the issue somewhat is, I added external filters over the fan intakes. That helps but they still suck in some dirt in the shop when running.

I will at some point, convert them both to 'fan on demand'. I have the adjustable snap thermostats on hand, just have to modify them both.

30 amp 220-1 will run them both no issue. Cannot speak for the wire gage as I had my electrician do my wiring.

I will say that neither machine will run satisfactorily on a 110-1 circuit.

Efficiency wise, the IGBT inverter machine will be much more economical to run but then I would not purchase that machine anyway as there are much better machines out there that will include everything, including the foot pedal for a much better price point.

I have no idea why you favor the Hobart and really don't concern me. All I know is that Harbor Freight offers a much less (and more complete) multi process machine(s) that are IGBT inverter based and have things like fan on demand and come complete with everything for a lot less jack.

I have 2 of the HF machines, one multi process and one TIG only and both have a 3 year warranty on them.

If you are going to run flux core, then no shielding gas is required but if you going to run solid core wire and are contemplating TIG, you need a shielding gas bottle for the MIG (75-25) as well as a 100% argon bottle to run TIG.

I suggest buying the bottles rather than renting them. Weld fabulous sells full bottles of both on their website and I have them in both flavors, 120 cubic feet. They are somewhat costly to buy but that beats any rental fee in the long run plus my LWS fills them no issue. I actually have 2 120 Cubic Feet 75-25 and 2 120 cubic feet argon bottles in the shop. One bottle of each on the welding cart and 2 spare bottles in the corner. Nothing worse than running out of gas in the middle of a job.

 

[UncleW]

I’m surrounded by opportunities

I have the AC welder, a DC inverter stick welder, and an oxy-acetylene rig. Gave my MIG/argon welder to my son in law cause I didn’t use it much with all the other options. The AC welder will do 220 amps if I need it for really thick stuff, which my inverter won’t, so it’s worth keeping around.