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

[GPintheMitten]

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.

Cat driver, he's not asking about a 3 wire sub. He's stated he has 4 wires going to the sub.

 

[aczlan]

Cat driver, he's not asking about a 3 wire sub. He's stated he has 4 wires going to the sub.

Correct. I have 4 wires going to the subpanel (which is currently bonded, but I will get that fixed this winter).
My question is if I can share the neutral and ground from the subpanel with the genset.

Aaron Z

 

[kenmac]

Sounds like you're just back feeding from 1 box to another ?? This will work. I do this from my swimming pool sub panel . Would it pass code. I doubt it. But, It works for me

 

[CobyRupert]

Correct. I have 4 wires going to the subpanel (which is currently bonded, but I will get that fixed this winter).
My question is if I can share the neutral and ground from the subpanel with the genset.

Aaron Z

Yes. Just make sure the neutral of the gen set isn't bonded/jumpered to the genny's frame/ground lug. The ground to neutral bond should only be at 1 spot, which already exists at your main panel. (Unless you install a transfer switch that has a switched neutral, which would be rare, but they do exist.)

 

[CobyRupert]

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

What type of interlock are you referring to? The danger with generators is not being isolated from the utility line (i.e. running generator with your main panel main circuit breaker feeding into the utility line). This presents a danger to utility linemen who may be working on the line. The problem you have is wanting the sub-panel's breaker on when you have both utility power and when you are using it to back-feed the main panel (if that is what you are suggesting?).

 

[GPintheMitten]

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.

 

[aczlan]

What type of interlock are you referring to? The danger with generators is not being isolated from the utility line (i.e. running generator with your main panel main circuit breaker feeding into the utility line). This presents a danger to utility linemen who may be working on the line. The problem you have is wanting the sub-panel's breaker on when you have both utility power and when you are using it to back-feed the main panel (if that is what you are suggesting?).

A physical interlock that will keep the genset breaker and the main breaker from being on at the same time.
My plan is to run new power wires (red/black) from the subpanel to the main panel, share the neutral and ground wires and just use the subpanel as a junction box, the generator will not connect to any breakers in the sub panel.

Aaron Z

 

[aczlan]

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.

Exactly in the case of the power wires. My purpose in starting this thread was to see if the neutral and ground can be shared.

Aaron Z

 

[buickanddeere]

if there was male prongs on both ends of the cord then it's dead wrong.

 

[boggen]

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 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.

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.

but for a 30 amp unit, i would say save your cash on wiring, and get a honda unit, they are the quitest units i have found, granted ya pay for brand name with them, but for small generators. they really can not be beat. and i seen same like comments over and over again over the years on the internet and word of mouth from other folks. heck 30amp unit is set outside main door of a 20x24 cabin, and powers cabin, ((completely off grid)) granted only a couple lights, can be on, and needing to turn stuff off to run a small microwave, or run a small a/c window unit, but shrugs. 30amps not that much, and fairly easy to over use them to point ya get brown out condition (not enough power coming out of them) and overload switch gets thrown.

larger diameter wire able to hold a little bit more amps/watts on a generator can go a long ways. been there done that. from regular 12/3 to 12/3 wiring, to extension cords. a small little 30 amp generator just does not have the power to handle long lines of wire when undersized, or barely meet specs for regular 110v stuff.