Only one conductor per terminal?

[Dale001289]

Is this a true statement?:
"Control wiring should have only one conductor per terminal unless otherwise Listed for more than one." This is coming from one of the inspectors, but I cant seem to find that language in the NEC.

 

[Eddie702]

I don't see how that is possible. I doubt there is an NEC rule on this.

 

[infinity]

Look at 110.14(A).

 

[charlie b]

(OK, Infinity beat me to the draw on this one. But I'll post it anyway.)

How about the "catch all" that tells us to comply with the instructions in the product's listing?

 

[Dale001289]

(OK, Infinity beat me to the draw on this one. But I'll post it anyway.)

How about the "catch all" that tells us to comply with the instructions in the product's listing?

Charlie are you referring to 110.3(B)?

 

[infinity]

Charlie are you referring to 110.3(B)?

Thst would apply. You mentioned control wiring is this a control panel?

 

[Dale001289]

Thst would apply. You mentioned control wiring is this a control panel?

Yes in most cases it will be a control panel application

 

[Little Bill]

@Dale001289
Would you please update your profile to include your occupation? That info was lost when the Forum changed platforms.

 

[infinity]

Yes in most cases it will be a control panel application

I think just about every industrial control panel I've ever worked on had more than one conductor under a DIN rail terminal. I'm not sure if those terminals are listed for more than one conductor or if ANSI/UL 508A Standard for Industrial Control Panels actually permits it. Either way if it's part of a listed control panel IMO the NEC doesn't apply to how it's wired in the factory.

 

[jim dungar]

I'm not sure if those terminals are listed for more than one conductor or if ANSI/UL 508A Standard for Industrial Control Panels actually permits it.

I don't think I have ever seen a terminal block that was not rated for at least (2) #12AWG control size conductors.
I know the panels I built under UL508A often had multiple conductors in terminals.

 

[infinity]

I don't think I have ever seen a terminal block that was not rated for at least (2) control size conductors.

Jim, where would you find that information? I don't recall seeing it on a label in the control panel. Here's an example of factory wiring with more than one conductor under a terminal:

 

[jim dungar]

Jim, where would you find that information?

It would be found in the terminal manufacturer's literature.

 

[infinity]

It would be found in the terminal manufacturer's literature.

If the terminal has multiple conductors and is part of the factory wiring (as in the photo in post #11) is it covered under the NEC? I say no if it's in a listed control panel and therefore the inspector should have nothing to say about the factory wiring.