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

[aczlan]

My inlaws have a barn on the outside of a paved U shaped driveway and a house on the inside of the driveway.
There is a conduit running to the barn that brings power out from the house, it has 3 #6 stranded wires in it for power, neutral and 4th wire for ground.
We are thinking of setting it up to run a generator out there (to reduce sound in the house), would I be able to share the same neutral and ground to feed back to the panel and just pull new wires for the power wires (so that I can install an interlock in the main panel)?
Currently, the generator I would use puts out less than 30 amps, so a 10/3 would be enough (and would fit in the conduit), but I would like to size the wires to run up to a 50 amp generator in the future and while there is space to put in either a 10/3 or 2 #6 wires, I don't think I could fit 3 #6 wires and a ground.

Aaron Z

 

[MossRoad]

Is there a subpanel in the garage?

 

[s219]

With two interlocks you could just use the existing wiring.

I wouldn't pull new wire in the existing conduit unless you were sure it was large enough to satisfy code. There are rules about the number, size, and current load of wires for a giving conduit size. So you often can't add more wires even though there appears to be space.

Also, be sure to factor in voltage drop if there is a distance from barn to house, so that you don't lose a lot of voltage when running off generator. I had about 100' from generator shed to house, and had to upsize wire by two sizes in order to keep voltage drop low. So consider what is needed for the amperage and then figure voltage drop considerations will drive the size larger.

 

[aczlan]

Yes there is a subpanel in the barn. The conduit is 1 1/4" (I think, haven't measured it, but it looks to be 1 1/4").
It is not more than 100' from the barn subpanel to the main panel in the house.
Looking at the fill table at: http://sparkyjohn.com/pipefill/pipefill.pdf it appears that I could put 11 #6 wires in a 1 1/4" conduit, so conduit capacity shouldnt be a problem as long as I can pull them through (I would prefer to avoid removing the existing wires from the conduit if possible).

Aaron Z

 

[aczlan]

With two interlocks you could just use the existing wiring.

How would 2 interlocks 100" apart work?

I wouldn't pull new wire in the existing conduit unless you were sure it was large enough to satisfy code. There are rules about the number, size, and current load of wires for a giving conduit size. So you often can't add more wires even though there appears to be space.

There should be enough space per the table linked in my last post.

Also, be sure to factor in voltage drop if there is a distance from barn to house, so that you don't lose a lot of voltage when running off generator. I had about 100' from generator shed to house, and had to upsize wire by two sizes in order to keep voltage drop low. So consider what is needed for the amperage and then figure voltage drop considerations will drive the size larger.

Per Voltage Drop Calculator at 150' #6 copper in conduit should be good for up to 50 amps of 240VAC with a 3% voltage drop.

Aaron Z

 

[JBourquin]

I can see putting an interlock in the sub panel but wouldn't one in the main panel prevent you from feeding the sub panel when on grid power? Of coarse with only one in the sub panel it's going to prevent you from feeding back to the main panel in the first place.

 

[GPintheMitten]

Here's a thought but I don't know if it violates code or not. Maybe a pro can weigh in on it.

The idea is to bring your subpanel feeder wires to a 4 wire receptical. Then have a short plug to connect your subpanel to the receptical. Then when needing the generator you unplug the barn panel and plug in the generator. Then you wouldn't need to pull any more wires thru the conduit.

I see two problems with this, but with exercising care one could switch over. One is there would be no proper interlock and two the generator input would be a male plug.

As to using the neutral and ground feeding the panel, I can't think of why that wouldn't be appropriate.

 

[CobyRupert]

How would 2 interlocks 100" apart work?

A Kirk-Key set up, one at the main panel utility main breaker, one at sub-panel branch circuit breaker to the genny. The common key to enable the genny breaker is only released from the main panel's main breaker lock when the main is in the off position & vise versa.

 

[jaotguy]

I see two problems with this, but with exercising care one could switch over. One is there would be no proper interlock and two the generator input would be a male plug.

one could also wire a receptacle to the gen set and make a male to male connection cord ( so no male end is "live" by accident)...

 

[buickanddeere]

Here's a thought but I don't know if it violates code or not. Maybe a pro can weigh in on it.

The idea is to bring your subpanel feeder wires to a 4 wire receptical. Then have a short plug to connect your subpanel to the receptical. Then when needing the generator you unplug the barn panel and plug in the generator. Then you wouldn't need to pull any more wires thru the conduit.

I see two problems with this, but with exercising care one could switch over. One is there would be no proper interlock and two the generator input would be a male plug.

As to using the neutral and ground feeding the panel, I can't think of why that wouldn't be appropriate.

Don't even mention such a code violating and dangerous scheme . Somebody looking for the quickest, easiest and cheapest generator connection is going to look for somebody to "approve" such a hazard.
The transfer switch with the interlocked breakers or the double pole/double throw break before make switch has to be together and at the utility common supply to all buildings.

 

[buickanddeere]

one could also wire a receptacle to the gen set and make a male to male connection cord ( so no male end is "live" by accident)...

No you don't ever use a cord live live male prongs. What is wrong with you jackleg hacks ?

 

[buickanddeere]

Just install a proper auto start Generac or Kohler genset in a sound and weather enclosure at the utility pole. It will switch over and run everything with it's properly installed transfer switch.
Or run a new cable or conduit out from the shed and mount this panel at the central power pole. Then install one of these .Products - Reliance Controls Corporation

 

[jaotguy]

No you don't ever use a cord live live male prongs. What is wrong with you jackleg hacks ?

please note : it was F receptacles on both the wall and gen set .... and a male male extension cord between them ( a lot of the big RV's use them too ) .... nothing live .... please read more carefully ...

special extension is disconnected from both plugs and hung up ... power goes out , plug in the special cord , start the gen set , then set the breakers ON to feed the house ( that has already been disconnected from the mains ) ...

turn gen set off , and breakers ,, ( dead all round ) then remove special cord and hang up till next time ...

if the OP wants to , he can bring in the special switches / wiring / experts and have them "do it right" .. no one is twisting his arm one way or the other ...

 

[GPintheMitten]

No you don't ever use a cord live live male prongs. What is wrong with you jackleg hacks ?

Nothing wrong with this jack leg hack. Ease up Buick.

 

[GPintheMitten]

I wish someone would answer his darn question about using the neutral and ground
How bout you buick. Give us an answer.

 

[milkman636]

A Kirk-Key set up, one at the main panel utility main breaker, one at sub-panel branch circuit breaker to the genny. The common key to enable the genny breaker is only released from the main panel's main breaker lock when the main is in the off position & vise versa.

A solution like this would require pulling no new wires between the house and barn.

 

[aczlan]

one could also wire a receptacle to the gen set and make a male to male connection cord ( so no male end is "live" by accident)...

Ummm, lets start with Nien, Nyet, No.

Just install a proper auto start Generac or Kohler genset in a sound and weather enclosure at the utility pole. It will switch over and run everything with it's properly installed transfer switch.
Or run a new cable or conduit out from the shed and mount this panel at the central power pole. Then install one of these .Products - Reliance Controls Corporation

A genset like that has been discussed, but the house is not currently setup with propane or natural gas and we have a diesel tank for the tractors.
3 problems:
1. U shaped PAVED driveway that goes right up to the front of the barn. No adding any more conduit underground.
2. Why would I want to pull the meter, add in a new panel ahead of the current one, then rewire the panel to split the neutrals and grounds when I can just add a generator breaker and an interlock to the existing panel?
3. Power comes into the house RIGHT next to the living room picture window and very much in view of the (busy) road... I would rather not advertize that we have a genset installed.

please note : it was F receptacles on both the wall and gen set .... and a male male extension cord between them ( a lot of the big RV's use them too ) .... nothing live .... please read more carefully ...

Can you show some examples of this dangerous (and potentially deadly) practice where it has been setup and/or recommended by an RV manufacturer?
I have seen a RV with generator and shore power FEMALE receptacles mounted side by side with a MALE plug going into the RV panel, but there is no way to make the male plug be live until its plugged in.

special extension is disconnected from both plugs and hung up ... power goes out , plug in the special cord , start the gen set , then set the breakers ON to feed the house ( that has already been disconnected from the mains ) ...
turn gen set off , and breakers ,, ( dead all round ) then remove special cord and hang up till next time ...
if the OP wants to , he can bring in the special switches / wiring / experts and have them "do it right" .. no one is twisting his arm one way or the other ...

Thats all well and good until someone is tired, in a hurry or ignorant of the proper procedure and forgets to shut off the main breaker, then either hurts someone or blows up their genset when the power comes back on. Or until the cord comes loose while the genset is running and someone touches the live end. There is a reason those are called suicide cords.
Not going to happen here, I would like to keep my family alive and unharmed thank you very much.
Whatever I do, there will be no way to have the genset hots connected to the "mains" power and no way to have a live male plug.

Currently, its looking like I will be pulling back a pair of #8 or #6 copper wires into the house and sharing the ground/neutral wires with the subpanel feed.

Aaron Z

 

[kenmac]

Don't know if It applies to what you are doing or not. If you are adding load to the existing wires, you also have to figure heat build up of the wires in the conduit.

 

[Cat_Driver]

electrical - Can I connect ground to neutral in a 3 wire outlet? - Home Improvement Stack Exchange

If you don't have an EARTH wire DO NOT BRIDGE NEUTRAL + EARTH! This is potentially lethal as AC NEUTRAL is -115VOLTS! Earth is used in conjunction with LIGHTNING ARRESTORS and SHORT CIRCUITS prevention mechanisms! If you want earth- you need to UPGRADE your entire electrical system. neutral to ground should be 0 volts. If it's not, then it's not a neutral. For 220v circuits in the US, you have two out of phase hot connections at 110v each in addition to a neutral. That said, any issue anywhere in the wiring could result in an energized ground

The Definition of Alternating Current illustrates a Sine wave of t(time) in + then the same span in - (50/60hz) . Direct Current is always equal to or greater than 0! The very reason Negative AC is lethal if connected in the incorrect manner! eg. Never use AC negative as a radio antenna! Besides, Neutral in AC is only for distinguishing reasons as in theory there is never a + or - pole in AC

"Neutral Wire Facts and Mythology". There is a difference between neutral and hot even in AC circuits. One of the differences is that the neutral is grounded, therefore you shouldn't receive a shock if you touch neutral. Also notice that some plugs are asymmetrical so that you can't reverse the neutral with hot(the reason for this is explained in the document at the beginning).


I don't believe this is up to code, but it will pass the test from a standard outlet tester. The problem I see is if any device plugged into the outlet comes into contact with a ground (e.g. water) and that path is more efficient than going all the way back on the neutral wire through the house wiring, then hot current going through any appliance and onto the neutral would come out the ground and possibly electrocute anyone in that path.

That said, I've seen this implemented and have lived in a home where this was done without dying, or even getting shocked. But the fact that the electrician that used this trick was missing several fingers should give you pause.

 

[GPintheMitten]

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.