Hendrix
Senior Member
- Location
- New England
Is this 75 or 90 degree cable??
#6 Alum. SER xhhw
- Thread starter Hendrix
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- Massachusetts
As odd as it sounds it depends which year NEC you are under, what you are using the SER for and how its run.
So add some details for us.
No a simple question to answer.
IMO, the key, and complication, comes from the fact that it's SER which trumps the XHHW.
Therein lies a problem, 338.10 regulates SER and it references other Sections for installation and handles the ampacity differently depending on the Code Cycle.
In the '08 Code for interior installs 338 requires SER be treatexd as NM which makes it a 90° cable which must be terminated as a 60° cable.
In '11 its'a 60° termination when it is in insulation and so forth. The answer therefore lies in the Code Cycle and the details of the insulation.'
(was typing as iwire gave a far simpler answer)
IMO, the key, and complication, comes from the fact that it's SER which trumps the XHHW.
Therein lies a problem, 338.10 regulates SER and it references other Sections for installation and handles the ampacity differently depending on the Code Cycle.
In the '08 Code for interior installs 338 requires SER be treatexd as NM which makes it a 90° cable which must be terminated as a 60° cable.
In '11 its'a 60° termination when it is in insulation and so forth. The answer therefore lies in the Code Cycle and the details of the insulation.'
(was typing as iwire gave a far simpler answer
)
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
The cable is 90C but it may be rated 60C or 75C depending- as the others stated
Hendrix
Senior Member
- Location
- New England
It is feeding a sub-panel. We're on the 2014.
I believe Art 338.10 is the same in '14 as it is in '11.
With that in mind:
Where installed in thermal insulation, the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.
If not installed in thermal insulation, you are back to 110.14 as your governing factor where, depending on termination, it may be terminated a 60° or 75° cable (most likely 75°) even though the actual cable may carry a 90° rating.
This would be the case regardless of whether you look at it as a SE cable or XHHW conductors.
With that in mind:
Where installed in thermal insulation, the ampacity shall be in accordance with the 60°C (140°F) conductor temperature rating. The maximum conductor temperature rating shall be permitted to be used for ampacity adjustment and correction purposes, if the final derated ampacity does not exceed that for a 60°C (140°F) rated conductor.
If not installed in thermal insulation, you are back to 110.14 as your governing factor where, depending on termination, it may be terminated a 60° or 75° cable (most likely 75°) even though the actual cable may carry a 90° rating.
This would be the case regardless of whether you look at it as a SE cable or XHHW conductors.
Carultch
Senior Member
- Location
- Massachusetts
So SER/SEU wire when in thermal insulation is treated by a similar rule as ROMEX, where the 60C ampacity is a new governing factor, regardless of the conductor's rating (usually 90C) or the termination ratings (usually 75C). Do I understand this correctly?
I suppose the rule may exist for Romex, because it is very common for it to be in thermal insulation.
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