250.119 Re-Identifying equpment grounds

[Greg1707]

250.119 allows the equipment ground in a multi conductor cable to be re identified. It seems to specifically allow this in NM cable. What is the need for this change?

 

[LarryFine]

I don't now the specifics, but generally the rules allow us to use cables the way they're manufactured.

 

[infinity]

250.119 allows the equipment ground in a multi conductor cable to be re identified. It seems to specifically allow this in NM cable. What is the need for this change?

Which part of 250.119 allows an EGC to be re-identified when using NM cable? 250.119(B) allows another conductor to uses as an EGC. You can use a 3-wire NM or MC cable for something like an isolated grounded circuit where you need two EGC's. The red conductor is taped green and used as the IG.

 

[LarryFine]

You can use a 3-wire NM or MC cable for something like an isolated grounded circuit where you need two EGC's. The red conductor is taped green and used as the IG.

With MC, I use the green conductor as the IG and strip all the red to use as the EGC.

 

[infinity]

With MC, I use the green conductor as the IG and strip all the red to use as the EGC.

That works too for MC cable.

 

[tom baker]

I have used this exception for multi conductor tray cable that is black white blue and reidentify the blue as green

 

[letgomywago]

It made more sense when people wanted isolated grounds in the home office too.

 

[don_resqcapt19]

It made more sense when people wanted isolated grounds in the home office too.

If the wiring method is NM, the receptacle was in a non-metallic box, and the breaker supplying the circuit was in the service panel, nothing was gained by adding an additional EGC for an isolated ground receptacle.

 

[tortuga]

I have used this exception for multi conductor tray cable that is black white blue and reidentify the blue as green

Yeah some tray cable does not include a green, which is odd.

 

[wwhitney]

Aside: what code section(s) specifies which conductors have to be insulated, as opposed to just covered?

For example, suppose I need to run 4 ungrounded conductors (including switched conductors), a grounded conductor, and an EGC between two non-metallic boxes on a 15A branch circuit using NM cable. Is it permitted to run (2) 14/2 NM cables, using one bare conductor as the EGC, one bare conductor as the grounded conductor (which would everywhere be either covered by the NM jacket or field insulated with white insulation/tape), and the four insulated conductors as the 4 ungrounded conductors? We could route the two cables one on top of each other to avoid creating a current loop and associated EMI.

Obviously that doesn't seem right, but am looking for the exact code citations. In particular if there's a section which says the grounded conductor for a branch circuit has to be insulated.

Thanks,
Wayne

 

[Greg1707]

250.119 allows the equipment ground in a multi conductor cable to be re identified. It seems to specifically allow this in NM cable. What is the need for this change?

I raised this issue after taking a code update online program. This update was covered and it was mentioned that this was intened to apply to NM cable. I asked because I did not understand the need for this change to the code.

 

[infinity]

I raised this issue after taking a code update online program. This update was covered and it was mentioned that this was intened to apply to NM cable. I asked because I did not understand the need for this change to the code.

What code cycle had a significant change and what was the change? I don't see much difference over the last 4 code cycles.

 

[tortuga]

Aside: what code section(s) specifies which conductors have to be insulated, as opposed to just covered?

310.3(D)

For example, suppose I need to run 4 ungrounded conductors (including switched conductors), a grounded conductor, and an EGC between two non-metallic boxes on a 15A branch circuit using NM cable. Is it permitted to run (2) 14/2 NM cables, using one bare conductor as the EGC, one bare conductor as the grounded conductor (which would everywhere be either covered by the NM jacket or field insulated with white insulation/tape), and the four insulated conductors as the 4 ungrounded conductors? We could route the two cables one on top of each other to avoid creating a current loop and associated EMI.

Obviously that doesn't seem right, but am looking for the exact code citations. In particular if there's a section which says the grounded conductor for a branch circuit has to be insulated.

Thanks,
Wayne

It would violate 300.3 and 310.3(D)

 

[suemarkp]

Maybe applies to repurposing old NM cable with no ground to a grounded circuit with a taped green ground. But you would need to be converting a -3 cable to a -2 type usage which seems uncommon.

 

[don_resqcapt19]

I raised this issue after taking a code update online program. This update was covered and it was mentioned that this was intened to apply to NM cable. I asked because I did not understand the need for this change to the code.

The only change since the 99 code was the removal of these words in the 2020 code.

Where the conditions of maintenance and supervision ensure that only qualified persons service the installation

The substantiation for this change was:

There is no logical reason why the requirement "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" exists for re-identifying conductors of a multi-conductor cable. No such requirement exists for reidentifying conductors sized 6 AWG or smaller in 200.6(A) or for conductors sized 4 AWG or larger in 200.6(B). No such requirement exists in 200.6(D) for reidentifying conductors of different systems that are installed in a raceway, cable, box, auxiliary gutter, or other type of enclosure. Section 210.7(C)(1), which covers the use of conductors in (multiconductor) cables with insulation that identifies them as grounded conductors, permits conductor insulations to be reidentified to indicate its use. Specific instructions are given for such reidentification. In addition, specific requirements are provided for use of reidentified conductors for switch loops. This reidentification of conductor insulation is permitted without a requirement for qualified persons in qualified occupancies. No such requirement exists in 210.5(C) for branch circuits for "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" only qualified persons perform these identification tasks. The identification of the grounded conductor in feeders simply refers back to 200.6 without additional requirement. Extensive requirements exist in 215.12 for identification of equipment grounding conductors and for ungrounded conductors. No requirement exists for such tasks to be performed by only qualified persons in qualifying facilities. General requirements for identification of conductors is found in 310.110. There is no requirement for identification "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" in Article 310. General requirements for identifying equipment grounding conductors are found in 250.119. As found in 250.119(A), re-identification of conductors 4 AWG or larger can be performed by anyone without restriction. Many other sections of the NEC permit or require identification. So far as this submitter can determine, there is no requirement similar to "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" to perform such identification. A companion public input intends to correct 200.6(E).

And the panel statement in accepting this change was:

The Panel edits the text. Many other sections of the NEC permit or require identification. There is no requirement similar to "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" to perform such identification.

There was no mention of NM in this change, and this change simply made this rule match similar rules in other code sections.

 

[wwhitney]

It would violate 300.3 and 310.3(D)

No 300.3 violation, but 310.3(D) is what I was thinking of, thanks. I see that the allowance for the grounded conductor to be bare or covered is limited to service conductors, e.g. 230.41.

Cheers, Wayne

 

[tortuga]

For example, suppose I need to run 4 ungrounded conductors (including switched conductors), a grounded conductor, and an EGC between two non-metallic boxes on a 15A branch circuit using NM cable. Is it permitted to run (2) 14/2 NM cables,

This part about using two 14/2 cables in your example is the violation of 300.3 (B)

 

[wwhitney]

This part about using two 14/2 cables in your example is the violation of 300.3 (B)

It is not, it is allowed under 300.3(B)(3) "Nonferrous wiring methods".

Cheers, Wayne

 

[don_resqcapt19]

This part about using two 14/2 cables in your example is the violation of 300.3 (B)

Not really. List items 300.3(B)(1) through (B)(4) act as exceptions and 300.3(B)(3) would permit that installation.

 

[wwhitney]

So does anyone makes NM cable with an insulated ground?

Cheers, Wayne