Running a new 230 V outlet

[canoetrpr Senior Member Find all posts View Profile Close canoetrpr]

I originally put a 230 V outlet right by my breaker box in my shop and have been using a welding extension cord I picked up to route power to where I use the welder. Pretty sure the extension cord is no more than 8 AWG.

I've kinda gotten tired of having the extension cord in my way and am looking to run a new outlet to a more convenient location.

I've got about 60-75 feet to run so I'm trying to minimize my cost. I have a MM210 which draws a max of 47.5 A. I could only find 40A and 60A breakers so I put on a 60A one. Didn't care about the price of copper then as I was only running a foot. I ran 6AWG.

Trying to figure out if it would be safe enough for me to run 8 AWG for the 60-75 feet and still keep it on the 60A breaker, or if I should pick up a 40A breaker to be safe. I expect that I won't be drawing more than 40A 90% of the time - although on my recent project I am running it on the highest tap.

Any advice here ? Can I just stick to the 8 AWG and keep my breaker? Or should I be either biting the bullet and paying the extra for 6 AWG copper? Will I generally be fine with a 40 A breaker for my MM210 you think?

[crawler Senior Member Find all posts View Profile Close crawler]

Millermatic 210 requires a 30 amp breaker. #8 wire is fine for a 30 amp 230v circuit. You could even get by with a #10 wire since you won't be running at 100% duty cycle.

[Sberry Senior Member Find all posts View Profile Close Sberry]

I would just as soon see it on a 50 max for that machine, any breaker 30 or larger will work and I guess I wouldn't have a problem with the 60 although if it has a number 12 cord technically it should be limited to a 50.
I looked, number 12 cord.

[canoetrpr Senior Member Find all posts View Profile Close canoetrpr]

Its quite odd but for my panel at both the home depot and Lowes, all I could find were 40A and 60A. I already installed the 60 so I'd like to reuse it.. but buying a new 40A won't break the bank.

Ok so sounds like I will be running 8 AWG which will save me some cash. Do you guys think it is safe enough for me to stick with the 60 A breaker if the MM210 is all I am running on it? Or should I also get a 40 A breaker to be safe?

[canoetrpr Senior Member Find all posts View Profile Close canoetrpr]

BTW - my 25 ft extension cord is 8 AWG and does perfectly fine. I measured my run today and it will be 50 feet so I really can't see things falling apart if I go with 8 AWG and stick to my 60 A breaker...since I am never drawing much more than the MM210 can.

I guess to be safe, I should just change the breaker.

[Sberry Senior Member Find all posts View Profile Close Sberry]

What brand of panel is this? Its probably safe enough to run it on a 60 but that machine by NEMA and NEC codes is limited to a 50 by the nature of the cord size that the machine comes with. I would just assume that some of the internal wiring, etc may play a factor in the short circuit ratings??? I believe it is in ART 400 somewhere, not exactly sure but those with minds greater than mine may know.

[canoetrpr Senior Member Find all posts View Profile Close canoetrpr]

This is a Siemens panel.

Its strange. You would think they would have 50 A breakers.

I suspect that I won't trip a 40A breaker even running it on tap 7 given duty cycle and the fact that I really don't weld that much. Heck my welder is typically going for no more than 60 seconds at a time! I think that the max draw for the welder is 47.5A so theoretically I could trip it on a high enough setting.

More than anything I think that the breaker in this case is providing short circuit protection and I suspect it will trip right away before 8 AWG wiring overheats on a short.

[MAC702 Senior Member Find all posts View Profile Close MAC702]

That's not really all that long a distance. I'd run it on a 40A or 50A breaker with #10 wire, with the receptacle labeled for welder use only.

[cope Senior Member Find all posts View Profile Close cope]

This is a Siemens panel.

Its strange. You would think they would have 50 A breakers.

I suspect that I won't trip a 40A breaker even running it on tap 7 given duty cycle and the fact that I really don't weld that much. Heck my welder is typically going for no more than 60 seconds at a time! I think that the max draw for the welder is 47.5A so theoretically I could trip it on a high enough setting.

More than anything I think that the breaker in this case is providing short circuit protection and I suspect it will trip right away before 8 AWG wiring overheats on a short.

My Lowe's also sells Siemens, but there isn't as much of a selection as for Square D or GE. I just bought a GE box kit with breakers, and it came with a 50 Amp 220 breaker. Lowe's also has 40 and 60 amp in stock.

[Grumpy Senior Member Find all posts View Profile Close Grumpy]

My Lowe's also sells Siemens, but there isn't as much of a selection as for Square D or GE. I just bought a GE box kit with breakers, and it came with a 50 Amp 220 breaker. Lowe's also has 40 and 60 amp in stock.

FWIW, I find that the big box stores don't sell everything we need. They only sell items that will sell. Why only 40 & 60 amp breakers? Hard to tell. You really need an electrical supplier whose not afraid to sell one 50 amp breaker a month.

[MAC702 Senior Member Find all posts View Profile Close MAC702]

It depends on YOUR area. My local Lowes and Home Depot both carry 50A breakers in Seimens, Seimens knock-offs, and both common types of Square D (QO and Homeline), plus most other denominations as well.

Interestingly, I bought a certain breaker at one Lowes and wound up returning it at another when I didn't need it. They took it back, but sorta complained because it wasn't a stocked item FOR THAT STORE, on the other side of the same town.

[DaveD Hobbiest Hack Find all posts View Profile Close DaveD]

If you have the funds I'd consider upgrading the wire size so you can pull full breaker amps some time in the future for something else you might buy/use.

I was glad I did that when just recently I got my first 3 phase machine (lathe) and built a rotary phase converter with a 10HP idler motor that I ran off the same line I use the welder on. Obviously they (lathe/welder) don't run at the same time.

[Hot Fingers Junior Member Find all posts View Profile Close Hot Fingers]

Branch circuits for equipment are designed by determining the size of the load first. The load also determines the minimum circuit breaker size and is sized to protect the wire installed.

If you install a 60 amp breaker, the wire must be large enough to carry 60 amps. The reason for this is that a smaller wire could overheat and start a fire without tripping the circuit breaker.

So in your case, buy the smallest breaker needed for your equipment and then select the wire size for that breaker. You can always use a larger capacity wire than the breaker but DO NOT use a smaller capacity wires due to the fire hazard involved! Please be safe!

Note: I am not an electrician, however, I have enough familiarity with the NEC codes to know they were created to prevent serious accidents and injury. Don't become a statistic to save a buck on wire or circuit breakers

[Nickoli Senior Member Find all posts View Profile Close Nickoli]

If you install a 60 amp breaker, the wire must be large enough to carry 60 amps. The reason for this is that a smaller wire could overheat and start a fire without tripping the circuit breaker.

I couldn't agree with you more on this statement! Tis the reason for electrical code! Although I don't think your welder is going to tax the wire you have but there is always that little thing that says "What If". What if you or someone else plugs something into it(future bigger welder/plasma) and draws more current than the wire can handle and causes a fire? Think of your savings then! Single Phase 220v is pretty simple in my opinion but yet you must respect it and the codes that govern it!

Just my spin on it!