OK let's divide this into two main sections, with AC power coming and going...
Preface:
I have a 15'x15' detached work shed located about 50' from my house (single family, 150A AC service). The work shed is weathertight, modern asphalt shingled roof, vinyl siding over CDX plywood, with a set of barn doors that open up almost the entire width of one side. The inside is unfinished with studs on 16" centers, and a poured concrete slab floor. There is currently no AC power in the shed, and it is unheated except for occasional use of a kerosene heater. In addition to needing AC power in the shed (which a typical 20A branch circuit will suffice for shop lights and perhaps a block heater for the tractor), I have another goal in mind as well while I have the trench open between the shed and the house. Read on...
1) AC power:
My plan is to run buried 1" dia Schedule 80 PVC conduit from the house out to the shed, using condulets/LB's at both ends to bring the conduit up out of the ground and through the cement basement wall and plywood shed wall. The conduit will be buried 18" the entire length. Through the conduit I would run three lengths of #12AWG THHN/THWN (black/white/green). In the basement, to get to the circuit breaker panel, I would wire-nut the THHN/THWN to 12-2 NM w/ground Romex in the condulet/LB. At the panel i will install a dedicated 20A GFCI breaker for this branch circuit.
At the shed I *believe* that for a detached structure I must use another small sub-panel, in this case a single or dual 20A breaker type (non-GFCI, as it's already protected upstream). I will need a pair of ground rods at the shed, AND I will need to separate N and ground at the small sub-panel. From the small sub-panel I can wire out a pair of outlets via 12-2 NM w/ground Romex and a switch for a cold-rated fluorescent fixture. For the most part I am copying elements of this diagram:
http://losdos.dyndns.org/public/misc/detached-feed-1.jpg
So far so good?
2) Generator backhaul:
I also want to be able to run my generator out in the shed (barn doors wide open of course, or with it out on the shed's cement apron if it is not raining/snowing) and not have to unroll a heavy, long cable back to the basement where the transfer switch will be located.
The generator produces 240Vac split-phase (4 wire output -- L/L/N, with ground) at a continuous 7.5KW with a momentary motor starting peak output of up to 10KW. The generator head has on it a pair of ganged 50A output breakers.
So, in ANOTHER, separate Schedule 80 1.25" PVC conduit in the trench, I would pull qty 3 lengths of #6AWG THHN/THWN(L/L/N), and qty 1 length of #10AWG THHN/THWN (ground). It is a little unclear to me from reading the NEC online info whether the ground needs to be the same gauge as the hots and neutral. From what I gather for this situation, for wiring protected by up to 60A breakers #10AWG ground wire is OK.
On the shed inside wall, after a short section of conduit I will install a box and the mating receptacle for the OEM-supplied generator cable (of course, the end of the cable is female, so there are no exposed energized contacts when the generator is running). For generator operation, I would connect up the heavy output cable to the aforementioned receptacle (which actually has male contacts), start the generator, flip the breakers on, and proceed to the basement.
At the basement end the heavy #6AWG THHN would be run inside conduit up to the transfer switch. The transfer switch would be wired into the main circuit breaker panel for selected circuits (fridge, some lights, well pump, etc) so that when the generator is running these circuits would be powered when the transfer switch is in the generator position.
extra credit) Finally, I would like to run some low-voltage wiring out to the shed as well. I believe I will have to use separate 3/4" PVC conduit for this as well. Primarily I would like to use the low voltage wiring to alarm the shed doors via my current house alarm system. So i would program a new wired loop zone into the system with magnetic door switches or some such out at the shed.
For the most part, the conduit (x 3) would look like this, copied from one of the tacked threads here:
http://losdos.dyndns.org/public/misc/detached-feed-2.jpg
Question:
Is there any reason I can not put the AC power out to the shed AND the generator backhaul wiring in the same (larger) conduit? Both runs would be THHN/THWN and appropriately sized. The low voltage wiring would be in a second, separate conduit.
Thoughts?
Suggestions?
Corrections?
Did I overlook something?
Thanks
Preface:
I have a 15'x15' detached work shed located about 50' from my house (single family, 150A AC service). The work shed is weathertight, modern asphalt shingled roof, vinyl siding over CDX plywood, with a set of barn doors that open up almost the entire width of one side. The inside is unfinished with studs on 16" centers, and a poured concrete slab floor. There is currently no AC power in the shed, and it is unheated except for occasional use of a kerosene heater. In addition to needing AC power in the shed (which a typical 20A branch circuit will suffice for shop lights and perhaps a block heater for the tractor), I have another goal in mind as well while I have the trench open between the shed and the house. Read on...
1) AC power:
My plan is to run buried 1" dia Schedule 80 PVC conduit from the house out to the shed, using condulets/LB's at both ends to bring the conduit up out of the ground and through the cement basement wall and plywood shed wall. The conduit will be buried 18" the entire length. Through the conduit I would run three lengths of #12AWG THHN/THWN (black/white/green). In the basement, to get to the circuit breaker panel, I would wire-nut the THHN/THWN to 12-2 NM w/ground Romex in the condulet/LB. At the panel i will install a dedicated 20A GFCI breaker for this branch circuit.
At the shed I *believe* that for a detached structure I must use another small sub-panel, in this case a single or dual 20A breaker type (non-GFCI, as it's already protected upstream). I will need a pair of ground rods at the shed, AND I will need to separate N and ground at the small sub-panel. From the small sub-panel I can wire out a pair of outlets via 12-2 NM w/ground Romex and a switch for a cold-rated fluorescent fixture. For the most part I am copying elements of this diagram:
http://losdos.dyndns.org/public/misc/detached-feed-1.jpg
So far so good?
2) Generator backhaul:
I also want to be able to run my generator out in the shed (barn doors wide open of course, or with it out on the shed's cement apron if it is not raining/snowing) and not have to unroll a heavy, long cable back to the basement where the transfer switch will be located.
The generator produces 240Vac split-phase (4 wire output -- L/L/N, with ground) at a continuous 7.5KW with a momentary motor starting peak output of up to 10KW. The generator head has on it a pair of ganged 50A output breakers.
So, in ANOTHER, separate Schedule 80 1.25" PVC conduit in the trench, I would pull qty 3 lengths of #6AWG THHN/THWN(L/L/N), and qty 1 length of #10AWG THHN/THWN (ground). It is a little unclear to me from reading the NEC online info whether the ground needs to be the same gauge as the hots and neutral. From what I gather for this situation, for wiring protected by up to 60A breakers #10AWG ground wire is OK.
On the shed inside wall, after a short section of conduit I will install a box and the mating receptacle for the OEM-supplied generator cable (of course, the end of the cable is female, so there are no exposed energized contacts when the generator is running). For generator operation, I would connect up the heavy output cable to the aforementioned receptacle (which actually has male contacts), start the generator, flip the breakers on, and proceed to the basement.
At the basement end the heavy #6AWG THHN would be run inside conduit up to the transfer switch. The transfer switch would be wired into the main circuit breaker panel for selected circuits (fridge, some lights, well pump, etc) so that when the generator is running these circuits would be powered when the transfer switch is in the generator position.
extra credit) Finally, I would like to run some low-voltage wiring out to the shed as well. I believe I will have to use separate 3/4" PVC conduit for this as well. Primarily I would like to use the low voltage wiring to alarm the shed doors via my current house alarm system. So i would program a new wired loop zone into the system with magnetic door switches or some such out at the shed.
For the most part, the conduit (x 3) would look like this, copied from one of the tacked threads here:
http://losdos.dyndns.org/public/misc/detached-feed-2.jpg
Question:
Is there any reason I can not put the AC power out to the shed AND the generator backhaul wiring in the same (larger) conduit? Both runs would be THHN/THWN and appropriately sized. The low voltage wiring would be in a second, separate conduit.
Thoughts?
Suggestions?
Corrections?
Did I overlook something?
Thanks