I am running service from my house to a detached garage through 90' of
buried conduit. I will be operating flourescent lights on one circuit
and outlets on another. The outlets will power a fridge, an
occasionally a battery charger, small tools, space heater, etc...
Initially my plan was not to install a sub panel in the garage, but
rather run two separate circuits from the service panel in the house
to the garage. In the future I'd like to have the option to expand my
voltage in the garage to 240V but at the current time this is not
needed. I think I may have made an early mistake that is not to late
to fix. So far I have run 2 lines of 14/2 romex through the conduit.
I understand that this is only 15 amps on each circuit and I was
thinking I should use 20 amp circuits (I know I should have used 12/2
wire). Howver, I purchased the 14/2 and don't have any 12 guage to
use. If I leave the 14/2 in will this be enough to power the garage
effectively? Also, does this give me the option to create a 240V
circuit in the future? If I did decide to switch to 12 guage wire
would it make sense to use a single 12/3 wire hooked to 2 separate 20
amp breakers at the main service in the house and split these in the
garage to the two 20 amp circuits through 12/2 wire? Both circuits in
the garage will be protected with GCFI outlets.
A buried conduit is considered a wet location, except possibly in dry areas.
Romex has type thhn conductors in it, which are NOT for use in wet
locations. You don't give the size of the conduit, but without installing
panels or grounding rods, you can run two 20 amp circuits, which could be
accomplished with a 12/3 UF cable or four individual # 12 THWN or similar
conductors. This would give you 20 amps 120/240 volts and would be adequate
for what you've described
If it's a decent, fairly straight and clean run, you could pull 3 #8 and
1#10 for the ground,THWN conductors, use a six circuit panel two ground rods
connected with #8 and a 40 amp breaker in the main panel
To run an electrical service to detached building, you didn't necessarily
have to pull a ground conductor with the feeder, you could establish a new
ground at the detached building by driving ground rods, which now is a
requirement for any service larger than two 20 amp circuits. The down side
of establishing an independent grounding system at the detached building is
that you can't run anything between the buildings that could become a ground
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