Wires run in walls without voltage

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JoeNorm

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I got called on an install where I ran CT wires(for residential monitoring) through the walls not in conduit. I phoned the manufacturer of the product specifically to ask about this because I was concerned. They said it was no problem. Where is this covered in the NEC? What are the important factors to consider? I imagine the listing of the wire plays into it? I am still not sure who is right, me or the inspector.

The wires are twisted pairs probably around 18awg, no outer jacket. I cannot remember the labeling on them. They are connected to CT's that go around the feeders in the main panel. I guess they must induce a little current but could not be too much.

thanks
 
As far as I've seen this is completely unaddressed in the code. They might be Article 725 circuits but I don't know what criteria are used to confirm that, especially whether they might be Class 1, 2, or 3. Sections of article 725 imply that those circuits don't need to be run in raceways, but as far as I've seen there's nothing that explicitly says yay or nay to that.

I'd point out to the inspector that they are not power and lighting circuits and ask them to quote you the code section you're violating. Definitely share what the manufacturer said. I'd be curious myself to see what they have to say, or what others on the forum have to say.
 
Interesting situation. The voltage across the wires from a CT will be quite low as long as it's properly loaded. But if there's an open circuit then the peak voltage could get quite high.
 
It would be under 725. Since the outputs of the CTs are not labeled as to the wiring required, the rule is you must then assume that a Class1, Chapter 3 wiring method is required.

Apparently the manufacturer doesn't know the NEC. Is the product listed?

-Hal
 
hbiss said:
It would be under 725. Since the outputs of the CTs are not labeled as to the wiring required, the rule is you must then assume that a Class1, Chapter 3 wiring method is required.

Apparently the manufacturer doesn't know the NEC. Is the product listed?

-Hal
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Hal, Can you expand on what you said about CTs needing to me labeled........? If the manufacture can provide this data would that suffice?

thanks
 
JoeNorm said:
If the manufacture can provide this data would that suffice?
Click to expand...

No. An inspector can't be expected to be shown something from a manufacturer. The rule is every power source must have a label as to the wiring requirements. If no label then you must default to Class 1.

Besides, you have low voltage wiring entering and mixing with line voltage in the panel. That right there is a violation if it isn't Class 1.

-Hal
 
hbiss said:
No. An inspector can't be expected to be shown something from a manufacturer. The rule is every power source must have a label as to the wiring requirements. If no label then you must default to Class 1.

Besides, you have low voltage wiring entering and mixing with line voltage in the panel. That right there is a violation if it isn't Class 1.

-Hal
Click to expand...

Can you cite the code sections for both those statements?
 
725.124 Circuit Marking. The equipment supplying the
circuits shall be durably marked where plainly visible to indicate
each circuit that is a Class 2 or Class 3 circuit.
Click to expand...

What that says is that if it's not marked as CL2 or CL3 it isn't either so it's Class 1.

See 725.136 for CL3 and CL2 separation from Class 1, power and light.

And what that says is that even if you did have CL2 listed CTs, you can't run the wiring in the panel without either proper separation, a barrier or reclassifying it as Class 1.

So how you want to change what is there is up to you. Could you use NM?

-Hal
 
They may be properly marked but hard to see and I never knew what to look for anyway.

Manufacture instructions are to NOT use NM
 
The CTs hav
hbiss said:
What that says is that if it's not marked as CL2 or CL3 it isn't either so it's Class 1.
Click to expand...

That's quite an extrapolation from the actual language. It also contradicts the exceptions in 725.121.

See 725.136 for CL3 and CL2 separation from Class 1, power and light.

And what that says is that even if you did have CL2 listed CTs, you can't run the wiring in the panel without either proper separation, a barrier or reclassifying it as Class 1.
Click to expand...

..."unless permitted by" one of eight subsections of that section.

I kindof think that CTs deserve their own section there, if they are 725 circuits. The CTs have to be in the same enclosure and can't be separated because their function is to measure the power conductors. And CTs are ubiquitous.

So how you want to change what is there is up to you. Could you use NM?
-Hal
Click to expand...

NM would screw up the CT measurement calibration.
 
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