When I built my garage, I didn't plan for something as big as a Millermatic 200, but I picked up a great Craigslist deal for it. Problem is that my dedicated welder outlet is 208V on a 30 amp breaker and the wire to that outlet is 10 AWG (As I recall, I used specs for a Millermatic 212 when I built). Distance from the panel to the outlet is about a 35 foot length of the Romex. Now..the Millermatic 200 manual recommends an input conductor size of 8 AWG and a 60 amp breaker. I'm not going to be doing any heavy-duty welding, and I'm wondering if I'll be okay by simply swapping my 30A breaker for a 60A, or is running a new wire a must?
Welder Wiring question
- Thread starter tampascl
- Start date
rockwithjason
Well-known member
nope, upgrade the wiring.
hidollartoys
Well-known member
Per NEC the conductor size for weldersis determined by multiplying the rated primary current by a duty cycle multiplyer based on the duty cycle of the welder(2005 code).
Heavy Metal Doctor
Well-known member
Never change the size of a breaker on existing wiring - the breaker is the size it should be to protect the wire and the building. You MAY get away with running the machine on the circuit the way it is now as long as you don't work beyond that 30 amp limit. You won't hurt anything and you could get away with it 'till you can upgrade the circuit to 8GA / 60 Amp.
hidollartoys
Well-known member
For dedicated welder circuits... the OCPD for the conductors can be up to 200% of the conductor rated capacity.
Sorry, but you say OCPD and I think Obsessive–compulsive personality disorder.
The welder is rated 200 Amps at 28 Volts DC at 60% Duty Cycle. Input at rated load output is 46 amps at 200V and 40 amps at 230V. What I'm hearing here is to go ahead and use what I've got and if I don't weld continuously for very long, I shouldn't have a problem. I'm a beginner, so I expect I'll be taking it easy for a long time.One thing I forgot to mention was that the receptacle I installed was the correct (for today's welders) NEMA 6-50 but the welder came with a 10-50 plug. Since they are both three-prong, is it correct to simply get myself a new plug and replace the end of the welder's power cord?
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porschedude996TT
Well-known member
Are you sure that you have 208v in your shop? It is strange to have that in a residence.
If you are using this at a lower capacity I see no reason to upgrade the service. The Big issue is protecting the wiring in the wall. As long as the breaker is sized so that the wire in the wall is protected then you have no safety issues. It may be inconvenient if you draw more than the breaker will allow and the breaker trips, but there is no safety issue.
NEC wiring code for welders was written is for commercial/industrial applications where there are dedicated services to each machine like in a factory. A factory installation would be setup as if all the machines (Welder, Mills, Lathes) would run at 100%. Normally these would be hard wired directly from the wall to the machine.
In your case you have a convenience receptacle for the garage. I would check your voltage, verify the wire size and number of conductors, whether the welder requires a neutral, and I think that you should be able to safely use a NEMA 6-30R for installation without a neutral, and a NEMA 14-30R for one that has a neutral. If the wiring is there, I would use the one with the neutral. I’m thinking that you have a 240volt ac, 30 amp service, not a 208volt service. My golden rule is “Never use the incorrect receptacle for the wiring in the wall.” By abiding by the rule the worst thing that can happen is a tripped breaker. The welder can be fit with whatever fits the receptacle. Never ever use a larger breaker than the wire can handle. Using a higher rated receptacle may confuse the next owner or someone who is a guest in the shop, but is not unsafe.
Receptacle Figure:
http://www.frentzandsons.com/Hardware References/plugandreceptacleconfiguratio.htm
If you are using this at a lower capacity I see no reason to upgrade the service. The Big issue is protecting the wiring in the wall. As long as the breaker is sized so that the wire in the wall is protected then you have no safety issues. It may be inconvenient if you draw more than the breaker will allow and the breaker trips, but there is no safety issue.
NEC wiring code for welders was written is for commercial/industrial applications where there are dedicated services to each machine like in a factory. A factory installation would be setup as if all the machines (Welder, Mills, Lathes) would run at 100%. Normally these would be hard wired directly from the wall to the machine.
In your case you have a convenience receptacle for the garage. I would check your voltage, verify the wire size and number of conductors, whether the welder requires a neutral, and I think that you should be able to safely use a NEMA 6-30R for installation without a neutral, and a NEMA 14-30R for one that has a neutral. If the wiring is there, I would use the one with the neutral. I’m thinking that you have a 240volt ac, 30 amp service, not a 208volt service. My golden rule is “Never use the incorrect receptacle for the wiring in the wall.” By abiding by the rule the worst thing that can happen is a tripped breaker. The welder can be fit with whatever fits the receptacle. Never ever use a larger breaker than the wire can handle. Using a higher rated receptacle may confuse the next owner or someone who is a guest in the shop, but is not unsafe.
Receptacle Figure:
http://www.frentzandsons.com/Hardware References/plugandreceptacleconfiguratio.htm
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sberry
Banned
The machine calls for an 8 wire. Some machines allow for 10 wire and 50A but this isn't one of them, really should have an 8 or better. This machine does not use a neutral.
No you need to avoid welding at high output current if you use the existing circuit. Starting out it's unlikely you'll need, or want, more than 150A which probably won't pop the breaker.
sberry
Banned
Its a matter of time and current, a machine rated at 20% could use a 10 wire, this machine is rated at 60, not that a home brew outfit would run it that hard but thats what the instructions by the mfg call for so thats the minimum we recommend.
Its one of the benefits of buying newer machines in a slightly different class, inputs are lighter. This MM200 is heavy duty, will probably put out way beyond 200A for shorter cycles than its rated output.
Its one of the benefits of buying newer machines in a slightly different class, inputs are lighter. This MM200 is heavy duty, will probably put out way beyond 200A for shorter cycles than its rated output.
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glockaddict
Member
- Joined
- Apr 21, 2010
- Messages
- 19
i wired mine on 6/2 g wire and a 50 amp breaker...the mm20 max out at 250 amps.
Pulled out the voltmeter this evening, and you are mostly right. It is 220 volt ac, 30 amp service.
hidollartoys
Well-known member
Sorry, but you say OCPD and I think Obsessive–compulsive personality disorder.
One thing I forgot to mention was that the receptacle I installed was the correct (for today's welders) NEMA 6-50 but the welder came with a 10-50 plug. Since they are both three-prong, is it correct to simply get myself a new plug and replace the end of the welder's power cord?
Per 2005 NEC a dedicated circuit for your welder is...... 40 amps x .78 (60%duty cycle multiplier) = 31.2 amp conductor. You can use a breaker (fuse) that is rated up to 200% of the conductor ampacity. Check out page 70-508 of the 2005 code.
Well, since I got such a great deal on the welder, after considering the good advice on this thread, the fact that I am not going to be doing much welding, and the fact that I wired my garage for a home- rather than industrial-type machine, I put the unit on Craigslist and made one-day profit of $200 bucks. Sold it to the first guy that showed up. Might have been able to make a few more bucks, but didn't want to do the Craigslist Shuffle for a few days. Will take that profit and apply it towards something that is more appropriate for me like a MM 180 or, at most, a MM 212. Will keep an eye out on CL and Pawn Shops, but might end up going to cyberweld.
Thanks for all the great education!
Thanks for all the great education!
Coach James
Well-known member
If a MM200 is not right, why would a MM212?
Around here, experienced welders will crawl over broken glass to get a MM200. I saw one guy offer my welding instructor a brand new 210 for his used 200.
Coach
Around here, experienced welders will crawl over broken glass to get a MM200. I saw one guy offer my welding instructor a brand new 210 for his used 200.
Coach
sberry
Banned
They are different machines, a 212 is a few generations newer, a 200 was pretty much an "industrial" machine for lack of better terminology, way different output ratings than a 212.