difowler44
Member
in Table 31012(a) it shows that #4 copper thhn could be used for a single phase dwelling service & feeder. For a detached residential garage you can run #4 thhn for a 100amp subpanel?
#4 thhn for detached garage residential service
- Thread starter difowler44
- Start date
- Location
- Illinois
- Occupation
- retired electrician
No, that permission only applies to conductors that serve the dwelling unit itself.
difowler44
Member
do you need a ground rod on the detached garage subpanel?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
This is a service with it's own meter?
letgomywago
Senior Member
- Location
- Washington state and Oregon coast
- Occupation
- residential electrician
You can do #4 cu on a 90a breaker and it's a cheap sweet spot or go to #2 AL. Just need a small enough calculated load of 85a.
It'll need it's own GEC system tied to the EGC not the nuetral even if it's 2 ft away from the house feeding it.
It'll need a EGC with the feeder
Make the builder put in a uffer rebar stub up if before pouring concrete It'll make life better.
It'll need it's own GEC system tied to the EGC not the nuetral even if it's 2 ft away from the house feeding it.
It'll need a EGC with the feeder
Make the builder put in a uffer rebar stub up if before pouring concrete It'll make life better.
- Location
- Tennessee NEC:2017
- Occupation
- Semi-Retired Electrician
#2 AL would be good for 90A
Seven-Delta-FortyOne
Goin’ Down In Flames........
- Location
- Humboldt
- Occupation
- EC and GC
310.12 only applies to the service or feeder for the entire load
So even in a situation where you might have a 320/400A main, and feed 2-200A subs, those feeders between the main and subs must be full sized.
Feeders to accessory structures, ADUs, garages, workshops, etc., can’t use sizing from 310.12.