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

[s219]

So tell me how do you manage interlocks and not have a condition where the generator can be connected direct to the utility

That's what the interlock prevents. I can't have both my back feed breaker and main breaker engaged at the same time. I have one of the simple interlocks that is designed and sold by GE for my GE panel. There are far more advanced types out there, off the shelf.

 

[milkman636]

From a practical standpoint the neutral and ground never get disconnected and are already adequately sized for the generator output. Plus the ground would be earth connected at the main panel. So they will work as the OP plans. So, is this a question of whether an inspector will buy into the plan?

 

[MossRoad]

Really, all you are wanting to do is put the generator in the barn and run a long extension cord from the genny to a breaker in your main panel that is interlocked, so that it cannot feed the main panel at the same time that the main power is on.

Your conduit is large enough.

You'll need a cable from the genny to an outlet (assuming you aren't hard wiring it).
An outlet.
A cable that runs from that outlet to the main panel in the house, NOT the sub panel in the garage.
A breaker in the main panel.
An interlock kit for that breaker in the main panel to select grid or genny power.

Don't try and be frugal and double purpose the ground and neutral for both functions. Why?
Because you'll confuse someone, somewhere, someday.

Don't run the wires for the genny through the sub-panel at all. Keep them seperate to avoid confusion.

Take a look at this schematic. It's probably similar to your current setup. Anyway, print it out and add in the genny circuit. Technically, I see no reason why you could not use the neutral and ground for both situations, as only the two hot legs are switched. I just would not do it because you'd have two wires running into the sub panel for the neutral and ground and two wires passing through the sub panel that do nothing. Keeping them seperate just makes more sense.

I have no idea if what you want to do would violate code or not. Running seperate would definately be up to code.

 

[MossRoad]

Thinking about it, all you are doing is saving the money on two lenths of wire. You still have to buy everything else. Its not that much money to do it with four wires instead of two. We know it will work with two, however, we still don't know if its legit to only use two. I guess that's a question for an electrical inspector. Glad we got that cleared up, eh??? :laughing:

 

[CobyRupert]

So tell me how do you manage interlocks and not have a condition where the generator can be connected direct to the utility ? -Kirk- key
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. No transfer switch required. No new cables between main and sub-panel required.

Tell me why again this isn't an application for a kirk key. I didn't understand your explanation.

 

[radioman]

Reading this thread is making my head hurt. Mossroad is the only post that makes the most sense and its pretty much what I did. I put my portable genny in my new garage in back of house. I have a plug from genny to go into the outlet in the new garage feeding 220. I have the plug outlet hard wired to old garage going into the transfer switch that is right next to the main panel. I cherry picked circuits I wanted to be powered by genny and wired in extensions that is only on hot side to transfer switch box. The transfer switch box has the interlock on it so I can turn off the cherry picked circuits to be within the specs of the genny and still know if the power came back on the circuits I did not pick for the transfer switch. This is the ideal setup that I think everyone should follow.

I think azclan should be running complete seperate wires (2 hots,ground,neutral) to the house into the transfer switch from the barn genny plug box.

The question of the day is - is it code/legal to running separate circuit into the SAME conduit? suppose its permitted - what is his plan to pull new wires in the already fulled conduit ? The way I see it he would need to disconnect the wires from breaker in house completely, pull one of wires (preferably the ground wire) with a string attached to it and pull it out if it not tangled. if it is, he looking at pulling the whole shebang wires out and pull it back in with new circuit attached. something tells me this cant be code with two circuits. I am sure you can add another hot and use same ground/neutral for an extra circuit in same direction, but an opposite highway of power in same conduit for two different purposes? no. doesnt sound right. sorry guys.

I really think he should be running a new circuit in new conduit . He would have to dig holes on both side of driveway and tunnel/burrow a hole under the driveway with new conduit. I really dont think its a good idea try to save time thinking it will save money using the same conduit. Suppose it was done and op croaks? then someone else wants to expand/update etc and has bright idea to use the same wires. For all he knows without hiring a professional to trace the circuit underground its just extra wires to use in the future.

 

[buickanddeere]

It's more money that what it's worth compared to a proper reliance transfer switch. Plus somebody will eventually loose the key and there will be no power .
As previously stated the doubling of cables in the conduit requires de-rating.
Doing this job on the cheap is going cost more in the long run.
Just put a Champion 7200/7500 generator in a generator lean to beside the shed. Run a 8/3 cab tire cord from the generator to one of those reliance transfer switches. Be legal, safe and have something that anybody can operate. Instead of some farmer fix cob job that somebody will burn out if you are away or in the hospital when standby power is required.

 

[daybreak1998]

Tell me why again this isn't an application for a kirk key. I didn't understand your explanation.

Howdy,
Because he is trying to be cheap. Any custom kirk key setup would cost more than doing it correctly with all new wire pulls.

Pull new wires through the conduit, and terminate with generator receptacle. A complete simple homerun back to the main panel with the interlock and dual pole 50 amp breaker.

done, functions correctly, and can be used safely.

 

[CobyRupert]

I see that a Kirk key lock is about $40 x2 locations = $80 and about 10 minutes of fastening. Don't think you can by a transfer switch and new cables from main panel (or transfer switch) to sub (or genny) for that. Plus pulling new cables into an existing used conduit and installing a transfer switch is going to take a whole lot of time and require utility power being turned off.
But whatever.....

 

[BX23D]

Really, all you are wanting to do is put the generator in the barn and run a long extension cord from the genny to a breaker in your main panel that is interlocked, so that it cannot feed the main panel at the same time that the main power is on.

Your conduit is large enough.

You'll need a cable from the genny to an outlet (assuming you aren't hard wiring it).
An outlet.
A cable that runs from that outlet to the main panel in the house, NOT the sub panel in the garage.
A breaker in the main panel.
An interlock kit for that breaker in the main panel to select grid or genny power.

Don't try and be frugal and double purpose the ground and neutral for both functions. Why?
Because you'll confuse someone, somewhere, someday.

Don't run the wires for the genny through the sub-panel at all. Keep them seperate to avoid confusion.

Take a look at this schematic. It's probably similar to your current setup. Anyway, print it out and add in the genny circuit. Technically, I see no reason why you could not use the neutral and ground for both situations, as only the two hot legs are switched. I just would not do it because you'd have two wires running into the sub panel for the neutral and ground and two wires passing through the sub panel that do nothing. Keeping them seperate just makes more sense.

I have no idea if what you want to do would violate code or not. Running seperate would definately be up to code.

In Ontario Canada this is not legal. A power supply line needs to be in a separate conduit from a feed line. Four conductor wire will be needed. Any wire, even in a conduit needs to be underground cable. The transfer switch uses all 4 wires and transfers the bonding to the generator. Make sure the generator is set to bonded mode. The cable depth is also regulated and if under a driveway needs further protection.
The bonding must be at the power source, main panel when fed from the utility and at the generator when powered from the generator. Do it right, and do it once. Don't forget to have it inspected.

 

[MossRoad]

Tell me why again this isn't an application for a kirk key. I didn't understand your explanation.

I think its because many folks think he wants to backfeed the main panel AND have power at the sub-panel at the same time. The assumption is a key would be an either/or situation and couldn't do both, but maybe it can?

However, he doesn't want to backfeed the main from the sub. He only wants to use the neutral and ground in both directions.

 

[MossRoad]

One more thing to think about....

If you try to pull new wires into a conduit with existing wire in there, you take a chance of "burning" the insulation with friction during the pull. It gets more likely the fuller the conduit, bends, etc... So, either pull out the old wires with a pull-string attached as you do, to use the string to pull them all back in one pull, or suck a rag or cotton ball on a string through the conduit with a vacuum cleaner, then use plenty of pulling lubricant to make it nice and slippery to help lessen the chance of burning the insulation when you pull in the new wires. Use some common sense.

Hahahaha me telling people to use common sense is like the pot calling the kettle black for sure! :laughing:

 

[MossRoad]

So, now you weigh the cheap, fast, good triangle... You can only pick two.

Cheap and fast, it won't be good.
Fast and good, it won't be cheap.
Good and cheap, it won't be fast.

 

[daybreak1998]

Howdy,
Wire usage in the conduit when he uses a proper interlock at the main service panel, and uses a 50amp dual pole for generator backfeed, under normal use, and then watch his power usage from that sub-panel during generator use.

wire pulling = it will really depend on how long a run and what if any bends.

 

[aczlan]

In Ontario Canada this is not legal. A power supply line needs to be in a separate conduit from a feed line. Four conductor wire will be needed.

Good thing this wont be done in Ontario.

Any wire, even in a conduit needs to be underground cable.

I am curious what type of wire you are talking about here. Do you mean UF cable, THNW or???

The transfer switch uses all 4 wires and transfers the bonding to the generator. Make sure the generator is set to bonded mode. The cable depth is also regulated and if under a driveway needs further protection.
The bonding must be at the power source, main panel when fed from the utility and at the generator when powered from the generator.

Can you give a source for this bonding requirement? Generac sells a CSA approved transfer switch and it ONLY switches the hots, the neutrals are always bonded together.
Transfer switch: Generac Power Solutions | Service and Support | Online Product Support | Generac Power Systems
Manual with wiring diagrams and schematics: http://soa.generac.com/manuals/RTSE200A3CSA/0H4556

Do it right, and do it once. Don't forget to have it inspected.

I agree, do it right and do it once. I will probbaly have it inspected, time will tell. It will be wired in a safe and foolproof manner no matter what.

Aaron Z

 

[aczlan]

If you try to pull new wires into a conduit with existing wire in there, you take a chance of "burning" the insulation with friction during the pull. It gets more likely the fuller the conduit, bends, etc... So, either pull out the old wires with a pull-string attached as you do, to use the string to pull them all back in one pull, or suck a rag or cotton ball on a string through the conduit with a vacuum cleaner, then use plenty of pulling lubricant to make it nice and slippery to help lessen the chance of burning the insulation when you pull in the new wires. Use some common sense.

Lots of pulling lubricant will be used and if we have a slow day at work one of these days, I will ask the plant electrician what he thinks about it.

Howdy,
Wire usage in the conduit when he uses a proper interlock at the main service panel, and uses a 50amp dual pole for generator backfeed, under normal use, and then watch his power usage from that sub-panel during generator use.
wire pulling = it will really depend on how long a run and what if any bends.

Barn to house is probbaly under 100'. Two 90 degree bends for sure, how it runs underground, I don't know, but where it goes into the wall at each end there are conduit boxes with removable covers
As for power usage, the barn subpanel MIGHT see 5 amps (@240vac) in the dead of winter unless I am working in the shop. The animal barn has a 750w heater (to keep the chicken coop above freezing) and up to 230 watts of heated buckets.

Aaron Z

 

[MossRoad]

It sounds doable. Just not sure about using the neutral and ground as you want to do. Good luckm and let us know how it turns out.

 

[buickanddeere]

Still can't share that neutral with the utility and generator.
Can't pull two more live lines from the generator into the same conduit with cables supplied from the utility .
There are transfer switches that do switch the neutral if the generator has the neutral bonded to ground inside the generator. The transfer switches that only switch the lines are for generators where the neutral floats free of earth connection.
What is closer to the barn? The utility pole with the meter base? Or the house electrical panel which is supplying the barn? Is the utility service 60,100 or 200amp ?

 

[MossRoad]

Still can't share that neutral with the utility and generator.
Can't pull two more live lines from the generator into the same conduit with cables supplied from the utility .
There are transfer switches that do switch the neutral if the generator has the neutral bonded to ground inside the generator. The transfer switches that only switch the lines are for generators where the neutral floats free of earth connection.
What is closer to the barn? The utility pole with the meter base? Or the house electrical panel which is supplying the barn? Is the utility service 60,100 or 200amp ?

Regarding transfer switches switching the neutral... Some do. Some don't. You have to check with your local code. If they say you don't have to switch the neutral, then you don't have to switch the neutral. Some utilities only require a double-pole double-throw switch to switch the two hot legs from utility power to generator power. The neutrals are tied together and the ground remains bonded in the main panel.

 

[buickanddeere]

Moss, I told you why the transfer switch does or does not switch the neutral.