I was asked if the following use of flexible cord was OSHA and NEC compliant. I am a safety officer and electical compliance is not my strength. I would appreciate all feedback. These conditions are in an industiral site, not construction site.
1. Can flexible cord be used to hard wire a electric arc welding machine directly to a main disconnect? (No plug or outlet.) The machine is removed occassionally for maintenance, but has to be calibrated every time it is returned to service so the removal is not done frequently. Monthly may be the most frequent this is done.
2. Can a flexible cord be hard wired to a disconnect at one end, with a receptacle at the other end? (I've heard it called a pig tail.)
The real question is if the welder is listed for cord connections at all. That could be the show stopper.
If so; Yes and yes with the caveats that this cord can not be run through the wall, raceway or other structure, it must be free from the likelihood of physical damage and it must have the proper strain relieving grips on each end.
If it does list a cord and plug connection, a better alternative is a cord and plug on the welder going to a fixed point receptacle using regular chapter 3 wiring methods
I agree with Greg, but...the 'gray area' is how often is the welder moved? "frequent interchange" (400.7(6)) is open to opinions. If you are the compliance officer, that would be your call. Common trade practices on my side of the Hudson is Chapter 3 wiring to a receptacle, and a cord with cord cap on the unit.
The second part of your question (pigtail) IMHO is NO Sounds like the cord is being used for fixed wiring. Again, the term 'pendant' is not defined within Article 100, and is also a 'gray area' and subject to opinion.
Article 400.7 & 400.8 spell out the 'can & cannots' for rubber cords.
The last 'cord' battle was for a fast food prep area with the equipment requiring cord connections for cleaning the lines. That AHJ was adamant; cord could not be hard wired from a 5x5 at the ceiling (flush), strain relief, and a cord cap all of about 4+/- feet. The AHJ wanted a TL receptacle in the 5x5 (flush at ceiling) and the cords on the equip to be long enough to reach. A few weeks of arguements, a trip to the Board of Appeals, and fast food won the appeal. BTW, cord caps were all pin/sleeve
That is pretty standard at a couple of the burger joints. They are legitimately a pendant so it will be a tough fight for the AHJ. The argument from the management is it prevents the employees from having to use ladders to disconnect the equipment. They fear falls (maybe into hot grease or griddles) more than electrical problems and OSHA will back them up. I saw a kid slip and stick his hand into a fryer once, It was not pretty. We got it in ice as fast as we could but the kid's hand was never the same.
You've all seen the pictures - many posted by me- of the outrageous things folks do with cords. Let's pause a moment, and reflect:
In nearly every one of those pictures, the use of a flexible cord was the least of the issues. There are almost always other issues that, IMO, are more important. Cord too small, cords being damaged, improper connections, etc.
Code may not make any distinctions as to the 'gravity' of a violation, but only a moron would claim that all violations were equally dangerous.
Nor is the NEC the only, or even the overriding, concern. However passionate we may feel, however 'dangerous' the situation may be. The discussion (above) regarding deep-fryers is one such example.
Nor is something good, or 'safe' just because the code allows it. Examples of such 'legal' idiocy that I have seen include lights over swimming pools and electric baseboard heaters in athletic SHOWER rooms.
My biggest rant, though, is against the automatic assumtion that if a cord is used, it must be wrong. Sometimes this assumption is even 'built in' to the 'listing and labling.' Well, that sword cuts both ways.
If it's against the 'listing and labling' to wire a water heater with a cord - regardless of the cord size or strain relief provided- is it not also a violation of the 'listing and labling' to remove a cord from a welder, only to replace it with a length of flex?
So what if the cord is hard-connected to a disconnect switch or junction box. IMO, anyone who considers running a cord inside a raceway just enough to make a connection to be a violation is a fool.
"Do not use a cord in place of a permanent wiring method." Well, you're not. You ran 'permanent' wiring as far as you could. Past that point, you're altering the equipment.
Is cutting off the plug altering the equipment? I say NO. I say this in part because there is no requirement that a particular plug be used; there is the issue of maintenance and repair, and because even UL is very careful to distinguish between the cord and what it's connected to. There are many products that are not UL listed, yet have a UL lable on the cord!
We also see this assumption arise EVERY time someone makes a pendant; it seems some folks are not able to ever imagine how a cord might actually BE part of a proper permanent wiring method.
Nor should we ignore "non-NEC' reasons that someone might take into consideration. For example, the theft of equipment, the desire to reduce cord 'clutter,' or the desire to put the LOTO point in a more accessible location.
Finally, do we KNOW it's a 'flexible cord' as described in the NEC? Not everything that looks like SO really is SO. If it's the cord that came with the machine, chances are it's an "appliance cord" and not addressed by the 'flexible cords' part of the code at all.
So the OP has a welder that's tied to a disconnect. If that's the biggest problem he has, that's a darn good shop!
Reno: I would say that IF someone had a welder that came from the mfg with a cord & cap, and someone removed that and connected it with NM, MC, AC, or a raceway & THHN/THWN-2 that may raise my eyebrow. Is it any 'safer'? I would say it would depend on the skill of the person that made the change, AND...is the flexibility of the original wiring method something to be considered? Is the NM, MC, AC, THHN etc stranded or SOLID?? Things to consider!
Local (NJ) trade practice is to 'hard wire' electric water heaters & furnaces. I have not seen anyone use cord, and honestly...I have no knowledge on hand IF either can be wired with cord.
Changing a cord cap (plug) from a twistlock 120v/20 amp) to a straight blade on a pool pump will be an issue. Replacment of a cord cap on a cooking appliance with a 'like' is no issue.
Putting a 20 amp male & female, 120 volt cap on a 100' length of 12/2 MN is that an issue. Is that done? Yes! Do I like it? NO! Do I 'tag it'? Depends! Why? Basically, is it SAFE?, is it wired correctly? How long will a solid conductor survive? That is a place for cord; would I tag a 'homemade' extension cord of SO/SJ, etc.; if it was safe & wired right, NO.
I think this cord cap thing is more U/L lawyer than safety but it is true. I was the authorized manufacturer rep and I could do any thing I wanted on the load side of the line cord but the machine was listed with a U/L cord and if I altered the cord I wasn't listed anymore. Rulz is rulz.