Bare or Covered Conductors 310.15 (C)(2)(D)

[BeaKen]

Correct me if I'm wrong, shouldn't this section apply to a different section; Ambient Temperature Correction Factors; T310.15 (B)(1) because it appears to talk about temperature ratings, and not conduit fill Adjustment Factors.

310.15 (C)(2)(D): Where bare or covered conductors are installed with insulated conductors, the temperature rating of the bare or covered conductor shall be equal to the lowest temperature rating of the insulated conductors for the purpose of determining ampacity.

 

[infinity]

Did you mean 310.15(D) in the 2020 NEC?

 

[Dennis Alwon]

Oregon is on the 2020.

 

[Dennis Alwon]

Correct me if I'm wrong, shouldn't this section apply to a different section; Ambient Temperature Correction Factors; T310.15 (B)(1) because it appears to talk about temperature ratings, and not conduit fill Adjustment Factors.

310.15 (C)(2)(D): Where bare or covered conductors are installed with insulated conductors, the temperature rating of the bare or covered conductor shall be equal to the lowest temperature rating of the insulated conductors for the purpose of determining ampacity.

I agree it probably should be under (B) not (C)

 

[BeaKen]

Correct me if I'm wrong, shouldn't this section apply to a different section; Ambient Temperature Correction Factors; T310.15 (B)(1) because it appears to talk about temperature ratings, and not conduit fill Adjustment Factors.

310.15 (C)(2)(D): Where bare or covered conductors are installed with insulated conductors, the temperature rating of the bare or covered conductor shall be equal to the lowest temperature rating of the insulated conductors for the purpose of determining ampacity.

Shucks!!! Correction; that's 310.15 (D)

 

[BeaKen]

Did you mean 310.15(D) in the 2020 NEC?

Yes, I did mean 310.15 (D) of the 2020 NEC. Thank you.

 

[BeaKen]

I agree it probably should be under (B) not (C)

If that is the case, what is the procedure for getting clarification on this code section if I'm not a member of the NFPA?

 

[infinity]

If that is the case, what is the procedure for getting clarification on this code section if I'm not a member of the NFPA?

What in this section do you feel that needs to be clarified? If you have a bare or covered conductor there is no insulation so when calculating ampacity adjustment you would use the insulation value of the insulated conductors. Do you feel that this is in the wrong section?

 

[BeaKen]

What in this section do you feel that needs to be clarified? If you have a bare or covered conductor there is no insulation so when calculating ampacity adjustment you would use the insulation value of the insulated conductors. Do you feel that this is in the wrong section?

Yes, I do feel that it is in the wrong section. Because it deals with temperature would it not be under (B) "Ambient temperature correction factors?"

I also have another question that came up while reviewing this code section in preparation for the Oregon Supervisors Exam. If there were bare conductors in the same conduit as insulated conductors, would the bare conductors be counted when applying T310.15 (C) (1)?

 

[don_resqcapt19]

Yes, I do feel that it is in the wrong section. Because it deals with temperature would it not be under (B) "Ambient temperature correction factors?"
...

It has nothing to do with ambient temperature...it has to do with the temperature increase where there are multiple current carrying conductors in a raceway or cable. It is in the correct location.

 

[BeaKen]

It has nothing to do with ambient temperature...it has to do with the temperature increase where there are multiple current carrying conductors in a raceway or cable. It is in the correct location.

Ahhhh. Ok, I get it. Thank you.

 

[wwhitney]

It has nothing to do with ambient temperature...it has to do with the temperature increase where there are multiple current carrying conductors in a raceway or cable.

That would suggest it should be (C)(3). But it's more general than that, which is why it's a separate subsection of 310.15.

For example, say you have a feeder with 75C insulation for the ungrounded conductors, a bare grounded conductor, and 90C terminations for the bare grounded conductor, and no ampacity correction or adjustment applicable. You'd still be limited to the 75C ampacity of the bare grounded conductor. Presumably because it may be in contact with the 75C rated insulation.

Cheers, Wayne

 

[infinity]

For example, say you have a feeder with 75C insulation for the ungrounded conductors, a bare grounded conductor, and 90C terminations for the bare grounded conductor, and no ampacity correction or adjustment applicable. You'd still be limited to the 75C ampacity of the bare grounded conductor. Presumably because it may be in contact with the 75C rated insulation.

Cheers, Wayne

I'm thinking that you meant SEC's and not a feeder in your example.