Sub Panel in garage.

[Black_Z28]

Hello, I'm just checking in to ask you guys if this sub panel looks right to you all. I took the panel off the sub, and the doors are open in the main panel. This is in a attached garage, and ran with 2-2-2-4 AL wire, I was told that's good because I can upgrade up to 100amps if I wish to in the future. The main breaker in the main panel is a 60amp breaker. I was thinking about adding a cover over the main wire from the main panel to the sub, just so I don't have to see it and the extra coax cables.

The sub panel is currently servicing a 30 amp GFCI for brewing, 20 amp for a compressor, and addition lighting. I think I may add some addition outlets in the future.

Thanks...

Pictures.

 

[pattenp]

The #2 Al is to be over current protected to no more than 90 amps as a branch feeder.

 

[wyliesdiesels]

Pattenp beat me to it.

Yes the ampacity of #2 AL is often misunderstood. 100a is only allowed if the wire feeds a dwelling. Otherwise 90a....

Your panel looks fine, other than being small. I would have installed a bigger one....

 

[Black_Z28]

The #2 Al is to be over current protected to no more than 90 amps as a branch feeder.

Ahh, thank you sir. I don't think I'll really need much more anyways. We'll probably outgrow the house before I outgrow the garage sub panel.

Pattenp beat me to it.

Yes the ampacity of #2 AL is often misunderstood. 100a is only allowed if the wire feeds a dwelling. Otherwise 90a....

Your panel looks fine, other than being small. I would have installed a bigger one....

Yeah, I know what you mean. But, I really don't need much more. The garage already had two dedicated circuits from the main panel, both 20 amps. So, really I have about 100 amps to the garage. The only other thing I might purchase is a welder...and I've never really welded before, so I won't be buying anything spectacular. So, I'll probably just get a 110v wire feed setup.

Thanks for you helps guys.

 

[Norcal]

Pattenp beat me to it.

Yes the ampacity of #2 AL is often misunderstood. 100a is only allowed if the wire feeds a dwelling. Otherwise 90a....

Your panel looks fine, other than being small. I would have installed a bigger one....

Yeah, cheaping out on the size of the panel can come back & bite you.

 

[MTW]

#2 Aluminum can be used @ 100A for residential feeders in some settings, per the table below.


However in your case a different rule applies because it's used for interior wiring and it's installed in insulation.

338-4-a
(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.

In your case #2 aluminum @ 60 °C, is rated for 75A
See The Table Below



MTW Ω

 

[pattenp]

The SER in insulation rule applies once a certain amount/% of the feeder is within insulation as to the total run. It's something like no more than 10 feet or 10% of the total run not to exceed 10 feet. I can't remember the actual code section but it has to do with wiring that carries two different amp capacities because of installation methods.

Also the 100A on #2 is only allowed if the SER is providing the total load as a service to the dwelling, not as a branch feeder to a sub-panel.

Edit: Selection of ampacity NEC 310.15(A)(2). The exception would apply if only a portion of the SER is within insulation and is less than 10% or 10 feet, whichever is less.

 

[sberry]

That's just dandy and the 60 is plenty. No worries. Never seen one trip in this type of garage. Even with occasional welding and 5 hp comp not that you got to run them the same time. Comp and 13A of air and some lights never.

 

[Executive]

#2 Aluminum can be used @ 100A for residential feeders in some settings, per the table below.


However in your case a different rule applies because it's used for interior wiring and it's installed in insulation.

338-4-a
(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.

In your case #2 aluminum @ 60 °C, is rated for 75A
See The Table Below



MTW Ω

Table 310.15 (B)(6) no longer exists in the 2014 NEC. Installers should check what version of the code is in effect in their jurisdiction. The 2014 NEC has a confusing system using an 83% multiplier to determine the size of service and feeder conductors to an entire dwelling unit.

Chris