Help getting welder wired in!

[gemini5362]

Gizmo I think what you call a current limiting fuse and what I call a fast blow probably have similar characteristics. Your guess on circuit breakers is very close to what I remember the person teaching the class putting out. He said it takes over 200 per cent of the rated value for a breaker to trip in less than a few minutes. It is one of the reasons that I worry about breakers with larger current capability than the wire that is connected to them. I used to do some industrial wiring but now where i work we have a whole group of seperate people that do that. I just have to fix things.

 

[wmgeorge]

As a licensed master electrician, been a journeyman since 1970, I can tell you, IF the folks who write the National Electrical Code, even has the slightest thought Article 630 which covers Electric Welders was not correct or safe it would be changed. For a Arc welder (hobby) with 20% duty cycle at the highest setting, take the nameplate rating X .45 that is what the wire is sized on. For welders: Fuse or C/B shall not be rated at over 200% of the conductor ampere rating. (This does not factor in voltage drop for long runs of wire.)

Local codes may vary. Welding outlets are for welders and should be marked so, not for plugging your toaster into...

"when your dead and gone, somebody won't make a mistake about what you have done and burn the barn down by using the 50amp breaker with wiring not made to handle it.
Think how bad they will talk about you and your wiring it that happens, not that it will matter to you."

This is the biggest part of the deabte. It is huge and goes beyond the rules. If I bought a house with a 50 amp circuit and a 50 amp plug I would not hesitate to plug a 50 amp load into it which could be a disaster.

 

[gemini5362]

WMgeorge I would not even begin to argue with your knowledge. For me personally I just think it is a bad idea to over fuse wiring. If you are going to run 20 amp wire then use a 20 amp breaker. If you are going to use a 50 amp breaker then use wire that is made for 50 amps. It might not be against the NEC but I feel that a policy of having the wire match the protective device is just a plain basic safety. The welder might not stress the wire but as I said in an earlier post something could happen to cause a shorted condition in the welder that changes the amount of current flowing through it. then you would have something with a lot higher current than you have the wiring too handle and you have a lot bigger circuit breaker than the wire it is supposed to protect. Maybe I dont understand basic wireing but I thought circuit breakers were designed to protect a circuit and I believe that the wireing from the breaker to the device is a part of the circuit. If you are basing the allowable deviation due to the duty cycle then what is the duty cycle of a welder. I have thought that it is the amount of time the welder will run at it rated max amperage before it shuts off due to overheating. If the thermocouple that detects overheating opens up what is the duty cycle of the welder now and how will that affect the wireing ?

 

[wmgeorge]

If it was un-safe it would not be in the NEC. I personally think the NEC is way overboard on a lot of stuff, and seems to be going more that way every year. But if you wired to Code, it would not be un-safe. #12 copper wire under some conditions, could carry as high as 32 amps 100% continuous, but the Code limits the fuse & C/B size to 20 amps, except for Welders. Welders since they are seldom, if ever run at 100% rating can therefor use smaller wire sizes than normal.

You can't go wrong with the #6 wire on a 50 amp fuse. I have a couple of welders, a Hobart 187 MIG, love it for fast clean welds. Plus a Harbor Freight TIG welder, the little 130/90 amp lunch box size. Seems "hotter" than the rating, does a good job with the stick side, and once you get used to a "scratch start" TIG instead of high freg start it does a nice job on stainless and mild steel. BG

WMgeorge I would not even begin to argue with your knowledge. For me personally I just think it is a bad idea to over fuse wiring. If you are going to run 20 amp wire then use a 20 amp breaker. If you are going to use a 50 amp breaker then use wire that is made for 50 amps. It might not be against the NEC but I feel that a policy of having the wire match the protective device is just a plain basic safety. The welder might not stress the wire but as I said in an earlier post something could happen to cause a shorted condition in the welder that changes the amount of current flowing through it. then you would have something with a lot higher current than you have the wiring too handle and you have a lot bigger circuit breaker than the wire it is supposed to protect. Maybe I dont understand basic wireing but I thought circuit breakers were designed to protect a circuit and I believe that the wireing from the breaker to the device is a part of the circuit. If you are basing the allowable deviation due to the duty cycle then what is the duty cycle of a welder. I have thought that it is the amount of time the welder will run at it rated max amperage before it shuts off due to overheating. If the thermocouple that detects overheating opens up what is the duty cycle of the welder now and how will that affect the wireing ?

 

[gemini5362]

BG that is what I was trying to say. If the NEC says it is safe it probably is. I just think that the idea of running #6 for the 50 amp breaker is a better way to go. Or if he wants to use the #10 then go with a 30 amp breaker. either way would be fine.


Wow,I am envious. Your comment that "Once you get used to the scratch start it works fine. " I hate to say this but I have access to a millermatic synchrowave 250 and I have trouble welding with that if I have to tig something. I have a Miller DVI with a spool gun so if I am at home welding I can use that

 

[fishpick]

I love my Hobart Stickmate AC/DC jobbie that got life from the work that accompanied this thread...

It's awesome...

Of course - it took like 4 tries - and the right rod (6013) to get my bushog up and running again... but today I hogged about 5 acres or nasty stuff and it held up fine - so looks like my welding class from a few years ago paid off... had to remember the "right" way to manage a horizontal weld... and the right rod makes all the difference in the world!

 

[SnowRidge]

I love my Hobart Stickmate AC/DC jobbie that got life from the work that accompanied this thread...

It's awesome...

Of course - it took like 4 tries - and the right rod (6013) to get my bushog up and running again... but today I hogged about 5 acres or nasty stuff and it held up fine - so looks like my welding class from a few years ago paid off... had to remember the "right" way to manage a horizontal weld... and the right rod makes all the difference in the world!

I have the same welder. Did you try 6011? It's pretty good for stuff that doesn't clean up well. Bush hogs come to mind.

 

[GaryBDavis]

Hey WMGeorge, I have a grounding question for you.

In my shop I have 2" EMT that runs around the entire shop. All my oulets are in groups of four spaced every 25' or so. I drop down to a 4x4 wireway where I have four dual gang boxes mounted. The outlet configuration varies depending on the location. A typical drop might have four 5-15 outlets, a 6-50 welder outlet, some light switches with one empty box for future.

My question is, do I need to run a separate ground wire back to the breaker panel for each dual gang box or can I run one large ground wire to each drop (4x4 wireway) and break it out from there? The rule I've been following is to have one ground wire for each breaker. I daisy chain all the outlets, switches, etc on the breaker to one ground wire.

All my wiring is stranded type run inside of EMT with metal wire ways and boxes. I use 12AWG for 20A, 10AWG for 30A and 6AWG for the 50A welder outlets.

I notice that if you buy 6-2 or 6-3 sheathed wire, the ground wire is smaller. Sometimes its 10AWG and in some its 8AWG. Since I'm running individual stranded wires inside of EMT conduit, I can run whatever size wire I need for the line and ground. So, how small of a ground wire can you run for a 50A welder plug with 6AWG wire for the line feeds?

Your expertise would be appreciated.

Thanks!

 

[Inspector507]

Hey WMGeorge, I have a grounding question for you.

In my shop I have 2" EMT that runs around the entire shop. All my oulets are in groups of four spaced every 25' or so. I drop down to a 4x4 wireway where I have four dual gang boxes mounted. The outlet configuration varies depending on the location. A typical drop might have four 5-15 outlets, a 6-50 welder outlet, some light switches with one empty box for future.

My question is, do I need to run a separate ground wire back to the breaker panel for each dual gang box or can I run one large ground wire to each drop (4x4 wireway) and break it out from there? The rule I've been following is to have one ground wire for each breaker. I daisy chain all the outlets, switches, etc on the breaker to one ground wire.

All my wiring is stranded type run inside of EMT with metal wire ways and boxes. I use 12AWG for 20A, 10AWG for 30A and 6AWG for the 50A welder outlets.

I notice that if you buy 6-2 or 6-3 sheathed wire, the ground wire is smaller. Sometimes its 10AWG and in some its 8AWG. Since I'm running individual stranded wires inside of EMT conduit, I can run whatever size wire I need for the line and ground. So, how small of a ground wire can you run for a 50A welder plug with 6AWG wire for the line feeds?

Your expertise would be appreciated.

Thanks!

GaryBDavis,
I know you asked wmgeorge these questions, but he hasn't answered yet, so I'll try to help you out if it's okay. There are three ways you could safely and reasonably do your grounding.
1. Pull a separate ground back to the panel for every circuit. 20A breaker would require minimum #12 ground. 30A breaker would require minimum #10 ground. 50A breaker would require #10 ground as well, yes even with #6 feeding the outlet.

2. Run one ground conductor from the panel sized to the largest size circuit breaker protecting the conductors you have in that 2" pipe. Tap off an appropriate sized conductor to feed what you have on your drop at that point.

3. The EMT is allowed to be used as the ground conductor on branch circuits. Attach a lug to the box at each drop location and run an appropriate sized ground conductor down to each drop based on circuit breaker size.

There are a few other things you need to consider too. Make sure EVERY ground wire is attached to any metal box it is spliced in or passes through. If using the conduit and wireways as the grounding conductor, which is allowed, make sure when you attach a lug to the wireway you must scrape the paint off and use a nut and bolt arrangement or a threaded hole. No sheet metal screws should be used. Be aware of the derating factors that need to be applied, especially in the 2" EMT, if you have more than 9 current carrying conductors in the conduit.

These comments may not follow popular opinion here on TBN, but they are based upon what would be allowed and deemed safe by the NEC, if you're in an area that has adopted that.

 

[wmgeorge]

Thanks for giving him the correct answer, I've been doing a honey - do job, ceramic floor tile. I'd rather be out working on my tractor!! I always run a ground wire in the shop or industrial application, in case the EMT connectors work loose. BG

GaryBDavis,
I know you asked wmgeorge these questions, but he hasn't answered yet, so I'll try to help you out if it's okay. There are three ways you could safely and reasonably do your grounding.
1. Pull a separate ground back to the panel for every circuit. 20A breaker would require minimum #12 ground. 30A breaker would require minimum #10 ground. 50A breaker would require #10 ground as well, yes even with #6 feeding the outlet.

2. Run one ground conductor from the panel sized to the largest size circuit breaker protecting the conductors you have in that 2" pipe. Tap off an appropriate sized conductor to feed what you have on your drop at that point.

3. The EMT is allowed to be used as the ground conductor on branch circuits. Attach a lug to the box at each drop location and run an appropriate sized ground conductor down to each drop based on circuit breaker size.

There are a few other things you need to consider too. Make sure EVERY ground wire is attached to any metal box it is spliced in or passes through. If using the conduit and wireways as the grounding conductor, which is allowed, make sure when you attach a lug to the wireway you must scrape the paint off and use a nut and bolt arrangement or a threaded hole. No sheet metal screws should be used. Be aware of the derating factors that need to be applied, especially in the 2" EMT, if you have more than 9 current carrying conductors in the conduit.

These comments may not follow popular opinion here on TBN, but they are based upon what would be allowed and deemed safe by the NEC, if you're in an area that has adopted that.