When am I allowed to use #2 Al SER on a 100 amp breaker

[strawburner]

Okay could somebody clear this up for me? I am installing a 100A. disco on the outside of a customers house right beside the meter from there I run into the residential house to the breaker panel that supplies the house only. Am I allowed to use aluminum 2-2-2-4 SER cable to the inside panel. Or do I need Al #1? I am on the 2011 code.

 

[Knuckle Dragger]

I have never had an issue installing 2/3 SER from an outdoor disconnect to the 100amp subpanel inside with the AHJ.

 

[iwire]

It carries all the power for the house so that's good.

Is the service 240/120 single phase?

 

[strawburner]

It carries all the power for the house so that's good.

Is the service 240/120 single phase?

Yes 240/120 single phase

 

[strawburner]

So the scenario where that wire would be good for only 90 amps would be if I was sub feeding another panel from this main panel? Correct?

 

[Stevenfyeager]

So the scenario where that wire would be good for only 90 amps would be if I was sub feeding another panel from this main panel? Correct?

One county inspector in IN (uses 2008 NEC), dosent allow #2 AL cable for 100 amps but does allow #2 AL individual conductors for 100 amps.

 

[Smart $]

So the scenario where that wire would be good for only 90 amps would be if I was sub feeding another panel from this main panel? Correct?

Supplying anything less than the whole dwelling... and that qualifies.

 

[infinity]

One county inspector in IN (uses 2008 NEC), dosent allow #2 AL cable for 100 amps but does allow #2 AL individual conductors for 100 amps.

Sounds pretty dumb any reason why?

 

[Dennis Alwon]

I assume it has to do with 60C vs 75C--- the old argument

 

[iwire]

I assume it has to do with 60C vs 75C--- the old argument

I think that is a reasonable conclusion.

 

[infinity]

I assume it has to do with 60C vs 75C--- the old argument

Where in 310.15(B)(7) {2011 NEC} does it say that?

 

[Dennis Alwon]

Where in 310.15(B)(7) {2011 NEC} does it say that?

It doesn't in the table but some inspectors use this

338.10(4) Installation Methods for Branch Circuits and Feeders.
(a) Interior Installations. 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.
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.

 

[infinity]

It doesn't in the table but some inspectors use this

I've heard that argument but I do not see how it applies when 310.15(B)(7) says that you can use a cable in the size listed in T310.15(B)(7).

310.15(B)(7) 120/240-Volt, 3-Wire, Single-Phase Dwelling Services and Feeders. For individual dwelling units of one-
family, two-family, and multifamily dwellings, conductors, as listed in Table 310.15(B)(7), shall be permitted as
120/240-volt, 3-wire, single-phase service-entrance conductors, service-lateral conductors, and feeder conductors
that serve as the main power feeder to each dwelling unit and are installed in raceway or cable with or without an equipment grounding conductor.

 

[Dennis Alwon]

I've heard that argument but I do not see how it applies when 310.15(B)(7) says that you can use a cable in the size listed in T310.15(B)(7).

I agree but some-- Gus is one, I believe , that saw it differently. Of course with the changes in the 2014 it is obviously that the cmp realized this was an issue and corrected it. Now you do have to consider all de-rating and adjustments

 

[augie47]

I agree but some-- Gus is one, I believe , that saw it differently. Of course with the changes in the 2014 it is obviously that the cmp realized this was an issue and corrected it. Now you do have to consider all de-rating and adjustments

I hear that a lot !!!
When Art 338 was changed the chairman of CMP1 was holding a IAEI seminar and he taught that 338.10 trumped 310.15. His opinion was not widely accepted (except for those of us "ones") although later changes in '11 and '14 seem to uphold that opinion (again an opinion).
I grew weary of fighting the battle and eventually accepted 310.15(B)(*) for the specific areas to which it applies ((240/120 residential service & whole house feeders). (ignoring 338.10)
Throughout the years I often find that section misapplied to other feeders, etc.

 

[infinity]

I agree but some-- Gus is one, I believe , that saw it differently. Of course with the changes in the 2014 it is obviously that the cmp realized this was an issue and corrected it. Now you do have to consider all de-rating and adjustments

Yes the 2014 took care of all of these questions with unknown answers. Since the OP is under the 2011 I don't see any wording that says you need to modify what's in the table regarding the use of cables.