Welding Cable...

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Marshal

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Minster, Ohio USA
New to the Forum, but have been using it as a resource for years. I have a question that's been bugging me for years and am hoping to get some feedback...

Situation:
480 volt feed from a bus duct or similar feeder to a disconnect on the shop floor to provide primary for a transformer. That transformer feeds X machine directly from secondary of transformer.

Question:
Is it allowable, or more importantly, is it NOT allowable to use Welding Cable from secondary of transformer to main lugs of machine?? The perception is that the highly stranded welding cable is easier to work with and can be smaller due to its higher current carrying capabilities. Something about it seems wrong to me and I would love to be able to back that up. NEC seems inconclusive on this...

thanks.
 
Does the machine in question vibrate/move or need to be moved or replaced frequently?
You have two questions really:
Can you use flexible cord instead of wireway (including flexible wireway)?
And if you are allowed to use flexible cord in the first place, is Welding Cable allowed by NEC for this use?
 
The machine does not need to remain flexible/movable. We have been setting transformers on the ground next to the machine and running conduit and/or sealtight to the machine itself.

The Welding Cable has been introduced simply to make it easier on the guys to dress it into the cabinet and land in the never-conveniently spaced main lugs. My argument is that it strikes me as poor craftsmanship and simply a bad install practice...
 
Welding cable, as such, is not a NEC recognized 300.13 Conductor. A similar cable, locomotive cable, is likewise not however, some locomotive cables (DLO) carry an additional listing such as RHH/RHW. You can use these just like any other conductor if you adhere to the fine conductor termination rules.
I am not aware of any welding cable that carries the NEC recognized additional listing but as far as flexibility is concerned the DLO/RHW cable should meet your needs. You would need to comply with the RHW ampacities and install it in a recewaay.
 
ActionDave said:
Yes, regular lugs.



Not using lugs or connectors listed for fine stranded wire. The proper ones are usually special order.
Click to expand...

https://www.nema.org/Technical/Documents/Bull_105_Fine-Stranded Connections.pdf

Thanks. Very helpful. My brain was trying to discount using this wire for that application on virtue of the Welding Cable being not allowed to be used in this manner. I didn't even think about whether or not our connections were listed for that wire...appreciate the insight. A short google search brought me to the bulletin linked above.
 
There are a few mechanical lugs sold that accept K stranding cables, but you have to look carefully. What most people do in order to use DLO cable is to use pressure crimp lugs, you must use the ones that SPECIFICALLY say they are for the odd ball sizes you will find (i.e. 262MCM, 444MCM etc.), but most suppliers offer those. That doesn't mean distributors have them in stock though, so be careful about running out during a project.

But again, to reiterate augie47's point, this is for DLO cable that is cross-listed as RHH/RHW (most are, but not all). "Welding cable" is NOT listed for any NEC related installation. It's only for welders. You can hold up a piece of welding cable and a piece of DLO side by side and be hard pressed to see the difference, but the different IS in the insulation, hence the ability for it to be cross-listed as a usable building wire.
 
Jraef said:
....
But again, to reiterate augie47's point, this is for DLO cable that is cross-listed as RHH/RHW (most are, but not all). "Welding cable" is NOT listed for any NEC related installation. It's only for welders. You can hold up a piece of welding cable and a piece of DLO side by side and be hard pressed to see the difference, but the different IS in the insulation, hence the ability for it to be cross-listed as a usable building wire.
Click to expand...
Just like DLO there is cross listed welding cable.
 
Jraef said:
There are a few mechanical lugs sold that accept K stranding cables, but you have to look carefully. What most people do in order to use DLO cable is to use pressure crimp lugs, you must use the ones that SPECIFICALLY say they are for the odd ball sizes you will find (i.e. 262MCM, 444MCM etc.), but most suppliers offer those. That doesn't mean distributors have them in stock though, so be careful about running out during a project.

But again, to reiterate augie47's point, this is for DLO cable that is cross-listed as RHH/RHW (most are, but not all). "Welding cable" is NOT listed for any NEC related installation. It's only for welders. You can hold up a piece of welding cable and a piece of DLO side by side and be hard pressed to see the difference, but the different IS in the insulation, hence the ability for it to be cross-listed as a usable building wire.
Click to expand...

I have used "welding" cable in several control panels for high amperage connections, usually involving 24V battery power to motors. In those cases, I've always used crimped insulated ferrules, and then installed the cable in terminal blocks, contactors, mechanical lugs, etc... I've been informed that my approach is deemed acceptable by at least two AHJ's, as they see the ferruled conductor as a single "wire." Purely anecdotal, but I've never had a failure yet, and some of these assemblies see pretty rough and high vibration treatment.

The finely stranded (class K) wire is much easier to work with, but my real issue is pulling it through even short sections of conduit, flex, or LiquidTite. The rubber insulation is "sticky" and doesn't pull well at all. Baby powder works amazingly well in those cases; put your wire (already bundled with tape at the pulling end) in a garbage bag and dump in a liberal dose of baby powder and shake to coat. Pulling is a breeze, and the panel shop always smells "fresh and clean" afterward :)


SceneryDriver
 
Welding cable has insulation that is interned for low voltages, like less than 50, and high temperatures. The fine stranding is for repeated flexing. True welding cable is not suitable for voltages even close to 480. It's great stuff to make jumper cables for cars with.

DLO is not the same as welding cable. It doesn't have to be flame retardant. DLO with multiple ratings to satisfy Chapter 3 is available, but I seriously doubt that there is any welding cable with such dual ratings.

Current capability is not a function of stranding. It's a function of how hot the insulation can get before it breaks down. That's why bare conductors are rated higher than insulated ones.
 
ActionDave said:
Yes, regular lugs.
Not using lugs or connectors listed for fine stranded wire.
The proper ones are usually special order.
Click to expand...

+1 on that. for fine stranded wire, i've had the best luck
with hypress lugs specifically for fine stranded wire....
those lugs will almost always have a die specifically for them.

i've never seen one that actually requires a die that i have
in the box. :rant:

when i've had to use mine rated cable, and land it on a
breaker, i use finger lugs, and heat shrink tube.
 
Fulthrotl said:
+1 on that. for fine stranded wire, i've had the best luck
with hypress lugs specifically for fine stranded wire....
those lugs will almost always have a die specifically for them.

i've never seen one that actually requires a die that i have
in the box. :rant:

when i've had to use mine rated cable, and land it on a
breaker, i use finger lugs, and heat shrink tube.
Click to expand...
We custom made a swage to spread a regular crimp on connector just enough to fit a welding cable. That was before we knew you needed a special size. Oops. Sometimes being resourceful can bite you in the butt.
 
K8MHZ said:
Welding cable has insulation that is interned for low voltages, like less than 50, and high temperatures. The fine stranding is for repeated flexing. True welding cable is not suitable for voltages even close to 480. It's great stuff to make jumper cables for cars with.

DLO is not the same as welding cable. It doesn't have to be flame retardant. DLO with multiple ratings to satisfy Chapter 3 is available, but I seriously doubt that there is any welding cable with such dual ratings.

Current capability is not a function of stranding. It's a function of how hot the insulation can get before it breaks down. That's why bare conductors are rated higher than insulated ones.
Click to expand...

don's link in post #7 would tend to say otherwise, IMO:
[h=1]SUPER VU-TRON WELDING CABLE 600 VOLT UL CSA RHH RHW[/h]
 
K8MHZ said:
Welding cable has insulation that is interned for low voltages, like less than 50, and high temperatures. The fine stranding is for repeated flexing. True welding cable is not suitable for voltages even close to 480. It's great stuff to make jumper cables for cars with. ...
Click to expand...
Most of the welding cable we see around here has 600 volt insulation, even the stuff that is not dual rated.
 
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