Generator in a outside building and powering the panel...

[aczlan]

have you called around, to see how much it would cost... to get one of them machines, that puts cables under roads, and like? no actual digging at surface it is all jetted through with water / drilling under the surface.

I dont need a new conduit, I have a 1 1/4 conduit out the the barn which currently has 3 insulated #6 copper wires and a ground wire in it. The fill table I found says that I should be fine with up to 11 #6 wires in a 1 1/4" conduit. If I have to pull 4 wires instead of 2 wires I will, but if I can run 2 new #6 wires instead of 3 #6 wires and a ground it will be easier to pull and cheaper.

i am a tad iffy on 30 amp generator. they are not that strong, more length of wire ya put on them, the quicker they go down hill.

Hence the reason I am oversizing the wire to make room for a larger one down the road.

i can understand putting a cable from main panel in house, to a generator plug on opposite wall of house. so you could just wheel a small generator over and plug it in. but seems a bit extreme placing it over by barn.
placing it in the shed, has some concerns of exhaust fumes / carbon monoxide gas.
when ya get into 50 amp plus, ok i will bite, placing generator out away from house, and by shed (on the outside) in its own little enclosure if need be, i will bite on that.

The thought down the road is to get something like a MEP-003 which will need to be away from the house. There is a corner of the barn where a generator could be mounted out of the way with a CO2 meter next to it and run the exhaust right outside and have the sound blocked from the house.

Aaron Z

 

[buickanddeere]

I dont need a new conduit, I have a 1 1/4 conduit out the the barn which currently has 3 insulated #6 copper wires and a ground wire in it. The fill table I found says that I should be fine with up to 11 #6 wires in a 1 1/4" conduit. If I have to pull 4 wires instead of 2 wires I will, but if I can run 2 new #6 wires instead of 3 #6 wires and a ground it will be easier to pull and cheaper.

I would be surprised if the electrical authority would allow either the shared neutral or running all conductors in the same conduit. It's what maybe 50-60ft? It's like paying for a 200ft run of 200amp wiring.



The thought down the road is to get something like a MEP-003 which will need to be away from the house. There is a corner of the barn where a generator could be mounted out of the way with a CO2 meter next to it and run the exhaust right outside and have the sound blocked from the house.

The building code requirements to operate a generator inside a building a quit strict and $$$. A generator shack on the side of the building with a roof, two walls and a floor would be better.
I have run Draiger gas tests around running equipment and you would be amazed how much CO there is in and around the area.

Aaron Z

..............

 

[CobyRupert]

If you read his post carefully you would see that he wants to run 2 hot leads from the main braker panel that would be bavkfed with the genny and he wants to install a interlock for the main disconnect and the genny backfed breaker in the same main panel. Its just that the wires from the gen are going to share the conduit between the house and barn.

Ah-ha! Interesting question.
From a practical point:
I don't see any danger with sharing the neutral and the ground as long as the capacity of the generator is equal or smaller than the feed to the subpanel. Presently the #6 neutral wire is (indirectly) "protected" by the (50 amp?) breaker in the main panel that feeds the sub-panel. When used for the generator it will be protected by the 30 or 50 amp breaker of the generator. It's interesting, because when you're running the generator you're using the neutral conductor to return (a smaller possible) neutral current in the other direction, it's not like you're doubling up or adding current on the neutral. There's no danger of it being overloaded. Without looking it up, I believe the ground can be shared.

From a Code compliance point: Wow. The code isn't really set-up for a question like that. There are codes (NEC 200.4 & 210.4, etc..) that say you can't use a neutral for more than one branch circuit without provisions, but your not using it for more than one circuit at a time. It's just that "what that circuit is" changes. It would be interesting to install it and if the inspector has a problem make him cite exactly which code section it violates.

With that being said, there is a code requirement (NEC 310.15(B)(3)(c)) that when you install more than 3 current carrying conductors in the same conduit the allowed ampacity for a given cable size is reduced. 5 conductors means current carrying conductors are rated at 80% of their ampacity. (The "trick" around this is if you based #6 awg ampacity on a 60C insulation rating (55 amps) (because of the terminations (NEC 110.14)) but it's really 75C insulated cable (65amps), you can calculate 80% of the 65amps=52 amps and still be good for a 50 amp breaker.

 

[CobyRupert]

I suppose one could make the argument that when the generator is running this shared neutral violates NEC 300.3(B): "All conductors of the same circuit and, where used, the grounded (neutral) conductor... shall be contained within the same raceway.." in that, although there's only 1 conduit per se, one could argue the neutral of the subpanel feeder is no longer in that raceway, neutral current is now taking the short-cut directly to the generator.
But that's sort of a insignificant mind-exercise/technicality. And also wouldn't apply for nonmetallic conduit. If the inspector has the ability to think-up that logical contortion give him a gold star!

 

[boggen]

pouring a small concrete slab a couple feet wide couple feet long say 4 inches thick, (some 2x4's) and a few bags of pre mixxed concrete. pretty easy job, even if manually mixing it in a wheel barrow.

a couple sheets of plywood and some paint, or a sheet or 2 of metal siding for a metal barn or like. and some 2x4's or 2x2's and you have a mini enclosure / shed / doll house if you will. for generator to set outside. if ya toss in some eye bolt's in while concrete is being poured, you can run a chain through eye bolts and around generator with a paddlock to keep it from being stolen.

working on small engines, (weed eaters, push lawn mowers, etc...) to just driving in vehicles tractors into sheds. exhaust fumes get ugly quickly. and the fumes may not collect in area right were fumes are being created, but be concentrated much more in certain parts of the shed, and move about some with just a smallish fan or little blowing wind / opening a door togo in/out a couple times.

below not best diagram in world. but... *shrugs* maybe some more encourgment in placing genertor outside the shed. if not finding / buying / or building something to enclose generator.

 

[s219]

No one has answered his question if he can use the neutral and ground in the conduit from the main and the sub from his genset.

I can't see why he cant. As he states the are separate at his sub in the barn and bonded at the main.

I am making the assumption that there will be another neutral wire added between the generator and the sub panel as part of this connection. And that neutral is sized the same as the main (or whatever is sufficient to handle the maximum current of the phases and loads of everything). If that's the case, the neutral will only ever see the right flow, and should be fine. The main concern is that the phases/directions are combined OK, and that seems like it will always happen.

But if it was me, I'd put in the proper interlocks and re-use all the wires instead of running two new hots. As long as the barn sub panel isn't needed when running off generator, it seems pretty convenient to use the existing wires....

 

[aczlan]

I am making the assumption that there will be another neutral wire added between the generator and the sub panel as part of this connection. And that neutral is sized the same as the main (or whatever is sufficient to handle the maximum current of the phases and loads of everything). If that's the case, the neutral will only ever see the right flow, and should be fine. The main concern is that the phases/directions are combined OK, and that seems like it will always happen.

Neutral and ground for the run to the genset will match the power output of the genset.

But if it was me, I'd put in the proper interlocks and re-use all the wires instead of running two new hots. As long as the barn sub panel isn't needed when running off generator, it seems pretty convenient to use the existing wires....

The barn subpanel is needed as it feeds the shop, the animal barn (and its water heaters, lights, etc) which could be needed depending on the time of year.

Aaron Z

 

[CobyRupert]

The barn subpanel is needed as it feeds the shop, the animal barn (and its water heaters, lights, etc) which could be needed depending on the time of year.

Aaron Z

....and it still could. Generator plugs into sub panel circuit, sub panel back-feeds main panel when required. Main panel feeds sub-panel when under utility power. A "kirk-key" type interlock at main and sub panel prevents generator feeding utility line. No new wires between subpanel and main panel required.

 

[buickanddeere]

But if it was me, I'd put in the proper interlocks and re-use all the wires instead of running two new hots. As long as the barn sub panel isn't needed when running off generator, it seems pretty convenient to use the existing wires....

So tell me how do you manage interlocks and not have a condition where the generator can be connected direct to the utility ?
The transfer switch has to either be at the utility pole and a pair of conduits run to and from the shed. Or the transfer switch mounted at the shed. With all the utility power being routed to the shed, through the transfer switch and back out a 2nd conduit to the utility pole.

 

[buickanddeere]

....and it still could. Generator plugs into sub panel circuit, sub panel back-feeds main panel when required. Main panel feeds sub-panel when under utility power. A "kirk-key" type interlock at main and sub panel prevents generator feeding utility line. No new wires between subpanel and main panel required.

The Kirk-Key can and does have it's applications but this isn't one of them.