Ampacity of SER as feeder

[Srv52761]

What is the ampacity of 2-2-2-4 aluminum SER used as a feeder for a sub panel.

I was just told you must use the 60° column and not the 75° column.

I just had my sub inspected at 90 amps and passed.

 

[infinity]

This section has changed several times, what code cycle are you under?

 

[Srv52761]

2017

 

[augie47]

Under the '17 Code, 90 amp is correct.

 

[Srv52761]

so, under the 2020 code we need to use the 60° column. What article/code is that under?

 

[infinity]

so, under the 2020 code we need to use the 60° column. What article/code is that under?

That's only for cables with a condcutor size of #10 or smaller in thermal insulation.
{338.10.(B)(4)(a)(3)}

338.10(B)(4) Installation
(a)Interior Installations.
(1) In addition to the provisions of this article, Type SE service-entrance cable used for interior wiring shall comply with the installation requirements of Part II of Article 334, excluding 334.80.
(2) Where more than two Type SE cables containing two or more current-carrying conductors in each cable are installed in contact with thermal insulation, caulk, or sealing foam without maintaining spacing
between cables, the ampacity of each conductor shall be adjusted in accordance with Table 310.15(C)(1).
(3) For Type SE cable with ungrounded conductor sizes 10 AWG and smaller, where installed in contact with thermal insulation, the ampacity shall be in accordance with 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 ampacity does not exceed that for a 60°C (140°F) rated conductor.
(b)Exterior Installations.
(1) In addition to the provisions of this article, service-entrance cable used for feeders or branch circuits, where installed as exterior wiring, shall be installed in accordance with Part I of Article 225. The cable shall
be supported in accordance with 334.30.
(2) Type USE cable installed as underground feeder and branch circuit cable shall comply with Part II of Article 340.
Exception: Single-conductor Type USE and multi-rated USE conductors shall not be subject to the ampacity limitations of Part II of Article 340.

 

[Greentagger]

Final ampacity will be based on equipment terminals which are normally limited to 75 degree chart. Thats where your 90 A breaker came int play.110.14(C)(1).

 

[infinity]

Under the '17 Code, 90 amp is correct.

I agree, #2 Al is rated at 90 amps from the 75° C column in T310.15(B)(16).

 

[Little Bill]

What is the ampacity of 2-2-2-4 aluminum SER used as a feeder for a sub panel.

I was just told you must use the 60° column and not the 75° column.

I just had my sub inspected at 90 amps and passed.

Just to be clear, the ampacity is not determined by what it's being used for, such as a feeder in your case. It would be determined on terminal temp ratings and, in some cases, what material it runs through, such as thermal insulation.