Another Welding Receptacle Question

[Dale001289]

Lets not turn the simple/obvious into an intellectual think tank. A disconnecting means has functions in addition to disconnecting conductors-- emergency situations and lockout/tagout scenarios are always part of the equation.
Sometimes even the NEC can become a little abstract.


Sent from my LG-K330 using Tapatalk

 

[ActionDave]

Lets not turn the simple/obvious into an intellectual think tank...

Let's not.

 

[Dale001289]

At least we can agree from a philosophical standpoint.

Sent from my LG-K330 using Tapatalk

 

[steve66]

Philosophically, doesn't meet the intent of the Code and is probably somebody's cost-saving brain storm.
What if you need to 'quick disconnect' under load? Would you still consider it safe?

Sent from my LG-K330 using Tapatalk

How does a receptacle not meet the intent of the code? To me a receptacle is all you need for the disconnect. It is an "integral disconnecting means."

What if you need to 'quick disconnect' under load?

That's a "what if" we don't need to consider. The code doesn't say a "quick disconnect" is necessary, and it doesn't say the disconnect has to be located at the welder.

 

[steve66]

"What intent of the code?"......

Intent of the code = SAFETY.

"Yes, I would be just fine with pulling a 6-50 plug on a welder under load".....

Horrible idea; unless the receptacle is equipped with arc-chutes. (they don't make those)

I don't see how adding another disconnect prevent anyone from pulling the plug under load? Especially since I don't see any requirement for that disconnect to be located nearby.

 

[jap]

Just to muddy the water a bit, the rule seems to state that the disconnect must be installed in the supply circuit.
If a receptacle is installed for the welder to plug into, then doesn't the supply circuit actually end at the receptacle meaning the disconnect in question would have to be ahead of that?

Mike Holt had a graphic of where the branch circuit began and ended at one time, showing it to be at the receptacle, but I cant find it.
It also showed a light fixture and a motor, but, those didn't have a seperable connection to the branch circuit.

JAP>

 

[steve66]

Just to muddy the water a bit, the rule seems to state that the disconnect must be installed in the supply circuit.
If a receptacle is installed for the welder to plug into, then doesn't the supply circuit actually end at the receptacle meaning the disconnect in question would have to be ahead of that?

Mike Holt had a graphic of where the branch circuit began and ended at one time, showing it to be at the receptacle, but I cant find it.
It also showed a light fixture and a motor, but, those didn't have a seperable connection to the branch circuit.

JAP>

That only applies when the disconnecting means is not an "integral part of the welder."

The plug is a disconnect that is integral to the welder. Therefore, it does NOT have to be a "switch or circuit breaker", and it does not have to be "in the supply circuit."

IMO, ActionDave had it right in his first response to this post.

 

[steve66]

Although I think ActionDave was right in his first post, and the receptacle is the disconnecting means, I just realized the OP also stated that:

The supply circuit does have a branch circuit breaker in the breaker panel

I would say that definitely meets the code requirement. No need to add another disconnect at the receptacle.

 

[gadfly56]

Although I think ActionDave was right in his first post, and the receptacle is the disconnecting means, I just realized the OP also stated that:



I would say that definitely meets the code requirement. No need to add another disconnect at the receptacle.

I don't see how that flies given the specific requirement in 630.13 pointed to by jumper at post #3.

Beyond that, the OP stated the welder has an ON/OFF switch. Does that qualify as a disconnect? If not, why not?

 

[jap]

I don't see how that flies given the specific requirement in 630.13 pointed to by jumper at post #3.

Beyond that, the OP stated the welder has an ON/OFF switch. Does that qualify as a disconnect? If not, why not?

Although the ON/Off switch does interrupt the current, I wouldn't consider it a disconnect in this situation.

Would you work on the welder with the welder switch shut off and left plugged in?

JAP>

 

[steve66]

I don't see how that flies given the specific requirement in 630.13 pointed to by jumper at post #3.
QUOTE]

IMO, the "switch or circuit breaker" requirement only applies to a non-integral disconnect.

Beyond that, the OP stated the welder has an ON/OFF switch. Does that qualify as a disconnect? If not, why not?

It's not a disconnect if it only opens one hot wire. (Its a NEMA 6 recept, so that implies 208 or 240 V, and we would have two hots. The switch may leave one connected.)

 

[gadfly56]

Although the ON/Off switch does interrupt the current, I wouldn't consider it a disconnect in this situation.

Would you work on the welder with the welder switch shut off and left plugged in?

JAP>

If there was a 2-pole disconnect upstream of the receptacle I'd still unplug it.

 

[Dale001289]

Just to muddy the water a bit, the rule seems to state that the disconnect must be installed in the supply circuit.
If a receptacle is installed for the welder to plug into, then doesn't the supply circuit actually end at the receptacle meaning the disconnect in question would have to be ahead of that?

Mike Holt had a graphic of where the branch circuit began and ended at one time, showing it to be at the receptacle, but I cant find it.
It also showed a light fixture and a motor, but, those didn't have a seperable connection to the branch circuit.

JAP>

I would agree with your interpretation, i.e. 'must be installed in the supply circuit'. This beckons an unwritten portion of the NEC known as 'common sense'. Its never a good idea to simply 'yank' a plug from a receptacle under load, even at the 120V level much less 208V, 240V or 480V. In my industry, Petro-chemical, the ensuing 'arc' could easily trigger in a catastrophic event (explosion/fire) within a Class I, Division 2 location. In general, a local disconnect switch is the best way to go. It meets the intent of NEC and makes the most sense.

 

[jap]

I would agree with your interpretation, i.e. 'must be installed in the supply circuit'. This beckons an unwritten portion of the NEC known as 'common sense'. Its never a good idea to simply 'yank' a plug from a receptacle under load, even at the 120V level much less 208V, 240V or 480V. In my industry, Petro-chemical, the ensuing 'arc' could easily trigger in a catastrophic event (explosion/fire) within a Class I, Division 2 location. In general, a local disconnect switch is the best way to go. It meets the intent of NEC and makes the most sense.

I was just bringing up conversation, when in actuality, I cant recall ever putting a disconnect just ahead of welding receptacle for all of the reasons others have already mentioned.

There is always going to be disagreement when arguing what is actually required by the code because some, including myself, tend to confuse what they think should be required and makes the most sense with what is actually required.

Just as our difference in opinion on the statement above that the higher voltages would make a difference in the amount of arc that was produced while yanking a plug out of a receptacle.

It would be my opinion that the size of the arc produce when yanking a cord out of a receptacle would more be dependent on the load connected to the circuit,
not the voltage of the circuit.

Hence the use of the term Disconnect and not Quick Disconnect or Emergency Shut off.
Most would not even pull a disconnect under a load if they didn't have to.
It's simply not good practice.

Although the local disconnect might be the best way to go in some peoples opinion, the receptacle and plug, if meeting the requirements, also meets the intent of the NEC and may make more sense to some for different reasons.


JAP>

 

[Dale001289]

I was just bringing up conversation, when in actuality, I cant recall ever putting a disconnect just ahead of welding receptacle for all of the reasons others have already mentioned.

There is always going to be disagreement when arguing what is actually required by the code because some, including myself, tend to confuse what they think should be required and makes the most sense with what is actually required.

Just as our difference in opinion on the statement above that the higher voltages would make a difference in the amount of arc that was produced while yanking a plug out of a receptacle.

It would be my opinion that the size of the arc produce when yanking a cord out of a receptacle would more be dependent on the load connected to the circuit,
not the voltage of the circuit.

Hence the use of the term Disconnect and not Quick Disconnect or Emergency Shut off.
Most would not even pull a disconnect under a load if they didn't have to.
It's simply not good practice.

Although the local disconnect might be the best way to go in some peoples opinion, the receptacle and plug, if meeting the requirements, also meets the intent of the NEC and may make more sense to some for different reasons.


JAP>

On my end of the industry (refinery, chemical and LNG), common practice is to string multiple, 3 phase 480V welding receptacles on a single branch circuit. NEC requires each welder be protected with an appropriately sized O/C device. Crouse-Hinds offers 480V receptacles with a combo disconnect/circuit breaker (EBBR series) built into the enclosure. I believe this scenario is optimal to comply with articles 630.11, 630.12 and 630.13. Admittedly, there is high cost associated with these receptacles.
Welders are unique in that current rises quickly when striking the arc and create some very high currents. I'm afraid I remain unconvinced the plug is a valid disconnecting means for this application. But I can appreciate the arguments that state otherwise.

 

[gadfly56]

On my end of the industry (refinery, chemical and LNG), common practice is to string multiple, 3 phase 480V welding receptacles on a single branch circuit. NEC requires each welder be protected with an appropriately sized O/C device. Crouse-Hinds offers 480V receptacles with a combo disconnect/circuit breaker (EBBR series) built into the enclosure. I believe this scenario is optimal to comply with articles 630.11, 630.12 and 630.13. Admittedly, there is high cost associated with these receptacles.
Welders are unique in that current rises quickly when striking the arc and create some very high currents. I'm afraid I remain unconvinced the plug is a valid disconnecting means for this application. But I can appreciate the arguments that state otherwise.

How so? 630.13 doesn't list the plug as an acceptable means. Only a switch or circuit breaker.

 

[jap]

How so? 630.13 doesn't list the plug as an acceptable means. Only a switch or circuit breaker.

Why wouldn't the circuit breaker feeding the receptacle outlet not cover this part of it?


JAP>

 

[Dale001289]

Why wouldn't the circuit breaker feeding the receptacle outlet not cover this part of it?


JAP>

It WOULD cover part of it - as long as its just one Welder/receptacle. When multiple receptacles are placed on a single branch circuit, as is often done in heavy industry, each welder needs to be individually protected. Sometimes, the welder itself has an integral O/C device, but if you're not sure about the vendor/welder etc, a separate CB should be included in the design.

One thing I've noticed about all members on the Forum, including myself; we all love to argue! But that's what makes it so much fun.

 

[gadfly56]

Why wouldn't the circuit breaker feeding the receptacle outlet not cover this part of it?


JAP>

For one welder it's fine. The argument is about the PLUG being a suitable disconnecting means.

 

[GeorgeB]

Eye arnt a lectricshun, but have worked with many while commissioning my electro-hydraulic installations. All large companies seem to connect maintenance welders (as opposed to production machines) with plug-in disconnects which have to be off to plug or unplug the cord. Is this not almost universal?