Welder

Status
Not open for further replies.
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I was asked to wire a tig (I think- maybe a mig) welder that can be wire to 120v or 240. At 120V there is an adapter for a 120V receptacle. At 240v there is another adapter by Miller that is clearly a 6-50P. The interesting thing is that the cap says 240 V 20 amps. Is this something about welders I don't know about or just a manufacturing error.
 
I am new to welders and a bit confused. Here is the nameplate. I believe I can use a 30 amp overcurrent protective device.

enhance
 
If this is a 211 welder then you use either a 15 or 20 amp overcurrent protective device in every case. I know that seems odd but that's per the manufacturer specifications.

I should modify this to say with any 240v application you could use either a 15 or 20 amp OCPD.
 
Is there overcurrent protection within the welder?

If so then 630.12(A) is likely already taken care of.

630.12(B) would allow overcurrent protection of 200 percent of conductor ampacity. So you could plug it into a 6-50 receptacle on a 50 amp branch circuit and have a 10 AWG or maybe even 12 AWG cord if the unit has overcurrent protection within it.
 
I don't believe the unit has an overcurrent protective device but I didn't check closly. My concern was a 50 amp cord cap marked 20 amps and the note on the nameplate hat states 20 amp circuit. Right now it is working on a 20 amp 120v circuit
 
Dennis Alwon said:
I don't believe the unit has an overcurrent protective device but I didn't check closly. My concern was a 50 amp cord cap marked 20 amps and the note on the nameplate hat states 20 amp circuit. Right now it is working on a 20 amp 120v circuit
Click to expand...
But are they using it at it's maximum ability? "turn up the heat" from the user's perspective and it might not hold on a 20 amp circuit. If they always weld same kind of things maybe they get by with the 20 amp circuit.
 
So why doesn't a welder have min circuit and max overcurrent protective device. Instead of all these I 1max etc it would be simpler to have max amps...
 
kwired said:
Is there overcurrent protection within the welder?

If so then 630.12(A) is likely already taken care of.

630.12(B) would allow overcurrent protection of 200 percent of conductor ampacity. So you could plug it into a 6-50 receptacle on a 50 amp branch circuit and have a 10 AWG or maybe even 12 AWG cord if the unit has overcurrent protection within it.
Click to expand...


It does have a reset button so I assume that is an overload protective device. I just went over there and checked-- It was right next door to me.
 
Dennis Alwon said:
I don't believe the unit has an overcurrent protective device but I didn't check closly. My concern was a 50 amp cord cap marked 20 amps and the note on the nameplate hat states 20 amp circuit. Right now it is working on a 20 amp 120v circuit
Click to expand...


I assume it it is similar to the Lincoln 210mp, which I have at my shop. It comes with 120v and 240v cords. It is limited to 100 amps output with 120 volt input. You have to have 240 volt input to get the full amperage output.
 
Dennis Alwon said:
I don't believe the unit has an overcurrent protective device but I didn't check closly. My concern was a 50 amp cord cap marked 20 amps and the note on the nameplate hat states 20 amp circuit. Right now it is working on a 20 amp 120v circuit
Click to expand...

The 20A note on the plate is for 120V
 
Welders are their own world, in addition to their own article 630 in the NEC.

Any 240V welding machine will likely be supplied with a 50A NEMA 6-50 plug because that is the typical "welding circuit" receptacle configuration. It is common to find these supplied with a 50-A breaker on #10 or even #12 wire. The low duty cycles of welders make this permissible.

I've had to educate more than a couple inspectors on welding circuits, and then they readily admitted they never even knew Article 630 existed.

That said, some of you engineers and really savvy guys on Codes might notice labeling discrepancies with the smaller machines, but the simple fact is that everyone knows that a 20A 240V welder is plugged into a 50A circuit everyday, all across the country. The only reason they come with the smaller plugs also are for versatility when the 50A receptacle isn't available.

I've been a welder longer than I've been an electrician. I own a dozen welders and have twice Beta-tested Hobarts before they were even released to the public, because I'm active on Hobart and Miller factory websites.

Only in the last generation of machines has inverter-based technology really made dual-voltage input machines popular and affordable.
 
own world indeed. half the time they do thier own wiring- how good that wiring is depends! since our welders so cable extensions (male and female ends) are all set up for that 50a recep, i have just kept with the 50. and #6awg. it still gets an appropriate circuit breaker rating but because he may be welding the far side of really big equip i just keep the conductors big. i cant quite remember what wierd currents i found when he was complaining about poor performance but big conductors fixed it all. also, they can crank up the welder voltage but max rating should cover this...correct me if im wrong mac702

p.s.- how many welders does it take to change a light bulb?
 
MAC702 said:
Welders are their own world, in addition to their own article 630 in the NEC.

Any 240V welding machine will likely be supplied with a 50A NEMA 6-50 plug because that is the typical "welding circuit" receptacle configuration. It is common to find these supplied with a 50-A breaker on #10 or even #12 wire. The low duty cycles of welders make this permissible.

I've had to educate more than a couple inspectors on welding circuits, and then they readily admitted they never even knew Article 630 existed.

That said, some of you engineers and really savvy guys on Codes might notice labeling discrepancies with the smaller machines, but the simple fact is that everyone knows that a 20A 240V welder is plugged into a 50A circuit everyday, all across the country. The only reason they come with the smaller plugs also are for versatility when the 50A receptacle isn't available.

I've been a welder longer than I've been an electrician. I own a dozen welders and have twice Beta-tested Hobarts before they were even released to the public, because I'm active on Hobart and Miller factory websites.

Only in the last generation of machines has inverter-based technology really made dual-voltage input machines popular and affordable.
Click to expand...

I get that but the plug itself is a 6-50P but it has written on the cap- 20 amps.

enhance
 
so the 6-50p is the nema #? oops...sorry. saw it.

always triple check wiring inside the welder. always! their could be confusion...

edit- I kmow you know...they can put what ever they want on the plug... they may want a stronger mate at a the recept? a better connection than what you'd get from a 20/30a 2p..
 
Last edited:
Dennis Alwon said:
I get that but the plug itself is a 6-50P but it has written on the cap- 20 amps.

enhance
Click to expand...

OEM type of product only intended to be used for specific items and not for general use?

Is it a molded to the cord type of cap or is it a replacement type? Would make even more sense to have 20 amp rating on it if molded to 12 AWG cord.
 
Yes, this is definitely only to be used for this piece of equipment as the other side has 4 slots for the cord to plug into. I didn't take a pic of the other side. It has threads so the cord can plug in and then you tighten a thread ring to hold the cord tight together.
 
Dennis Alwon said:
Yes, this is definitely only to be used for this piece of equipment as the other side has 4 slots for the cord to plug into. I didn't take a pic of the other side. It has threads so the cord can plug in and then you tighten a thread ring to hold the cord tight together.
Click to expand...
This is an adapter to run the equipment on 240 volts and you use a different adapter to run it on 120 volts?

I could see that being possible, series connection for high voltage parallel connection or even just half input winding energized for 120 volts. Half input energized also makes sense for reduced max output rating in the one particular configuration.
 
Status
Not open for further replies.
Top