100A detached garage subpanel

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Short.Circuit

Short.Circuit

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i've been reading some thread regarding this. have 2-2-2-2 al SER cable feeding a squareD homeline 100A subpanel in detached garage, there is a 100A bolt-on main in the sub. so, insp. sez, #2AL is good for 90 A (really, should have to go on 60C col, but no worries). i'll search around for a 90A breaker for the main panel in the house that's feeding the subpanel. fine... my question is, can the garage main breaker just used as a disconnect ? or do i have to find out if sqD even sells a 90A bolt-on main breaker for the subpanel. i don't think i can just remove the thing & make it a lug-panel (based on it takes more than 6 throws). thanks for any help...
 
augie47

augie47

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Tennessee
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State Electrical Inspector (Retired)
It would appearer the inspector overlooked a few things, but to the point of your question, the 100 amp breaker is fine as the "disconnect". The conductors are protected by the feeder breaker.
 
Sierrasparky

Sierrasparky

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Electrician ,contractor
Short.Circuit said:
i've been reading some thread regarding this. have 2-2-2-2 al SER cable feeding a squareD homeline 100A subpanel in detached garage, there is a 100A bolt-on main in the sub. so, insp. sez, #2AL is good for 90 A (really, should have to go on 60C col, but no worries). i'll search around for a 90A breaker for the main panel in the house that's feeding the subpanel. fine... my question is, can the garage main breaker just used as a disconnect ? or do i have to find out if sqD even sells a 90A bolt-on main breaker for the subpanel. i don't think i can just remove the thing & make it a lug-panel (based on it takes more than 6 throws). thanks for any help...
Click to expand...
Yes, you can use it as a is.
I always wondered is it possible to use the 90 deg colum use a 90 deg connector and tail of a piece of larger wire to the breaker. and rate the circuit as 100 amps?
 
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augie47

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Sierrasparky said:
Yes, you can use it as a is.
I always wondered is it possible to use the 90 deg colum use a 90 deg connector and tail of a piece of larger wire to the breaker. and rate the circuit as 100 amps?
Click to expand...

The breaker & terminations would prevent that per 110.14(C)
 
Sierrasparky

Sierrasparky

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Location
USA
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Electrician ,contractor
inspector 102 said:
Would table 310.15(b)(6) apply here since it is a feeder for the original service. #2 Al would be allowable for 100 amp in that case, correct. I see no problem with the install.
Click to expand...
I don't think is supplies a dwelling. But is a feeder in a SFD.
 
raider1

raider1

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Logan, Utah
inspector 102 said:
Would table 310.15(b)(6) apply here since it is a feeder for the original service. #2 Al would be allowable for 100 amp in that case, correct. I see no problem with the install.
Click to expand...

The garage feeder would not be a dwelling unit main power feeder and therefore you can't use Table 310.15(B)(6).

Chris
 
W

wwhitney

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Location
Berkeley, CA
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Retired
Sierrasparky said:
I always wondered is it possible to use the 90 deg colum use a 90 deg connector and tail of a piece of larger wire to the breaker. and rate the circuit as 100 amps?
Click to expand...
Yes, I believe it is allowed, as long as your 90 degree conductor terminates at both ends at 90 degree rated connectors, not at 75 degree rated terminals.

Cheers, Wayne
 
jwelectric

jwelectric

Senior Member
Location
North Carolina
ARTICLE 338 Service-Entrance Cable: Types SE and USE
II. Installation
338.10 Uses Permitted.
(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.
FPN: See 310.10 for temperature limitation of conductors.
(b) Exterior Installations. 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. Type USE cable installed as underground feeder and branch circuit cable shall comply with Part II of Article 340.

It wouldn?t make any difference how you tapped another conductor to the cable it would still be rated at 60 degrees.

Short.Circuit said:
i've been reading some thread regarding this. have 2-2-2-2 al SER cable feeding a squareD homeline 100A subpanel in detached garage, there is a 100A bolt-on main in the sub. so, insp. sez, #2AL is good for 90 A (really, should have to go on 60C col, but no worries). i'll search around for a 90A breaker for the main panel in the house that's feeding the subpanel. fine... my question is, can the garage main breaker just used as a disconnect ? or do i have to find out if sqD even sells a 90A bolt-on main breaker for the subpanel. i don't think i can just remove the thing & make it a lug-panel (based on it takes more than 6 throws). thanks for any help...
Click to expand...
If it is aluminum it must be protected by a maximum 75 amp overcurrent device.
 
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