Generator backfeeding into utility lines

[Jay4200]

No, it's not safe for electrical utility workers. It relies on someones memory to actually throw the breaker . There is always the possibility that someone will forget or someone will "do the guy a favor" and fire up the generator for him without knowing that he has to throw the main breaker first.

Nice thought, but not the case. A generator won't energize the lines if you close the main breaker closed. It loads down and instantly blows the generator on-board breakers. Done it.

JayC

 

[chopped]

So your saying if the main is disconnected and then the generator is coming on. and then you throw the main connected to the street it will just load up and blow the breaker on the generator?

 

[hr3]

As a side note to backfeeding the house...I'm just curious as to why my motor home is factory built to backfeed the 5K generator back into the coach using the AC source cord with no transfer switch, just a closed circuit. If it's so dangerous to do that, why would Gulf Stream design it that way?

This has nothing to do with the grid, obviously....I just noticed some saying this was bad for the house in general.

This is a typical rv system.. your transfer switch is in there somewhere,,It's totaly automatic as Airstream is very high end,,

 

[grsthegreat]

This is a typical rv system.. your transfer switch is in there somewhere,,It's totaly automatic as Airstream is very high end,,

Also if the airstream is not plugged into the utility to begin with, it cant possibly backfeed. And if it is plugged in it cant run power from the generator. This is NOT a residential structure that is constantly lugged" into the utility.

 

[doc_cottom]

My neighbor tried to backfeed without shutting of his main. The portable generator would only run for 2 seconds and stalled. Once he threw the main it worked fine. We only have 2 houses per transformer on a 1000 foot rightaway, he was at the beginning.

The only wire I can see being energized is a wire broken at the transformer/pole and still attached to the meter if the main is on..Otherwise the feed is infanite to the rest of the neighborhood, and no non-nuclear generator can handle powering everyone else.

Not advocating this, although I have back fed my house only with no issues.

I back-feed my house a few time a year. The detached garage is 100Amp from the house, underground. My house has an exterior main line disconnect switch. Flip that off, and lock it off, makes sure all the big amp items in the house are off, connect the gen-set to the welder's L-3 connector at the shops panel. and I have 20Amps/220V available. One thing I did was write up check lists, laminate them, and attach them to each point as needed.

 

[BobRip]

Or look into using a Generlink.

www.generlink.com

I have 400 amp service. This will not work for me. Good idea otherwise. One problem I have heard is that it will not connect to the generator if the utility is working. There is no way to test your connection. I may be wrong about this.

 

[daybreak1998]

I have 400 amp service. This will not work for me. Good idea otherwise. One problem I have heard is that it will not connect to the generator if the utility is working. There is no way to test your connection. I may be wrong about this.

Howdy,
Generlink is made for 200amp service. It is a collar which extends your meter out about 4 inches. There is a special cord end which plugs into it. see picture below. The generlink unit favors generator power. In other words, when you attach the cord, your meter disconnects from the utility, and your on generator power. That is how you test. 3 little lites along the bottom by the plug tell you if utility power is waiting on the other side. If its not lit, then the power from the utility is not there.

30amp Generlink cord set


For larger service
I too have 400amp service at a central farm distribution point. It was easier and cheaper to have my utility put in a special hook-up. Transconnect unit. Similar to the generlink, a special collar moves the meter out about 4 inches. It then has a special pigtail which connects another box. The other box has all the automatic transfer and disconnect circuitry. I have a full power plug (dual modular anderson 350amp gray with 2/0 pins) The same which is on the pto generator. see below




This really works well for me. I have feeds going out from here to the shop, run-in shed, barn, and large house. Each with there own panels.:thumbsup:

 

[JB4310]

So your saying if the main is disconnected and then the generator is coming on. and then you throw the main connected to the street it will just load up and blow the breaker on the generator?

Most likely, but not guaranteed. There is also a chance that your feed could go through the transformer and go out onto the primary lines at 12,000 to 18,000 volts. In other words the transformer can work in reverse.

JB.

 

[hr3]

daybreak1998

How does the price of your setup com pair to a 400a transfer switch ?? Looks like a nice setup..

 

[daybreak1998]

daybreak1998

How does the price of your setup com pair to a 400a transfer switch ?? Looks like a nice setup..

Howdy,
A LOT easier and cheaper. I looked all over the place and the 400amp transfer switch is made of gold. A lot really depends on your utility. I am in Northern Virginia, and have Rappahannock Electric Coop. Here is there pricing page of switches REC Electrical Services Prices I talked with them and was able to bump up into the next size switch. I also paid a little more than the $1,400 which is the 25kw.

If you look at the break down of what it would cost with;
400amp transfer switch
wiring
electrician labor
utility to pull meter and put back
permit
it really adds up. I am sure it would be more than the $1,400. And since the utility did it, they have a permanent permit

 

[Redneck in training]

I have a tombstone by the transformer. It has a switch allowing selection of the grid, all off, auxiliary power. If I use a generator I could connect the cable on the AUX terminals of the switch and select auxiliary power. It is simple, no back feeding is possible but it isn't automatic.
The switch is in Grid position.
Handle in horizontal position is all off.
Handle pointing down is AUX power.
I could possibly leave the handle in off position and wire in some way kind of transfer switch to make it automatic.

 

[grsthegreat]

I have a tombstone by the transformer. It has a switch allowing selection of the grid, all off, auxiliary power. If I use a generator I could connect the cable on the AUX terminals of the switch and select auxiliary power. It is simple, no back feeding is possible but it isn't automatic.
The switch is in Grid position.
Handle in horizontal position is all off.
Handle pointing down is AUX power.

Thats a cool idea.. i have never sen anything like that. :thumbsup:

 

[Redneck in training]

I think that this is a standard for farm service in the area we live.

 

[JB4310]

I have a tombstone by the transformer. It has a switch allowing selection of the grid, all off, auxiliary power. If I use a generator I could connect the cable on the AUX terminals of the switch and select auxiliary power. It is simple, no back feeding is possible but it isn't automatic.
The switch is in Grid position.
Handle in horizontal position is all off.
Handle pointing down is AUX power.
I could possibly leave the handle in off position and wire in some way kind of transfer switch to make it automatic.

That would work, it's basically a double throw 2 pole switch.
What do you have connected to the aux lugs now? Is it wired for a generator input somewhere on the house?

Also another set of wires not connected, is that for a future shop/ barn.
I see the double lugs for the load, good idea.

The good thing about that is you can totally disconnect from the grid, from the transformer forward on your property, so you could work on your main panel or whatever with no juice in the box or anywhere in the house. the only bad thing is you have to go out in the yard to operate it.

I don't think you could ever make that automatic though.

JB

 

[Redneck in training]

The tombstone was installed by the power company. The transformer is just behind it. This is where they put the meters. The tombstone has two sides. One is locked and sealed. There is the total power consumption meter. From there are wires to the switch on the "user" side. On the "user" side is also meter for heating.
At this point there is nothing connected to the AUX. The neutral lugs (on the bottom in the middle) look like (in the picture) connected to the AUX terminals but they are not. The picture shows the switch before I connected the wires for the shop.

 

[JB4310]

At this point there is nothing connected to the AUX. The neutral lugs (on the bottom in the middle) look like (in the picture) connected to the AUX terminals but they are not. The picture shows the switch before I connected the wires for the shop.

Ok I see in the close up, thanks.
You could of run extra wire in the trench for the aux line. or are you thinking of just putting the generator right next to the meter/ switch. That is, if you have plans for a genny at this time.

I'm sure it must be deceiving in the picture, but it looks very close between the neutral bar/lugs and the hot lugs.

JB

 

[BobRip]

Howdy,
Generlink is made for 200amp service. It is a collar which extends your meter out about 4 inches. There is a special cord end which plugs into it. see picture below. The generlink unit favors generator power. In other words, when you attach the cord, your meter disconnects from the utility, and your on generator power. That is how you test. 3 little lites along the bottom by the plug tell you if utility power is waiting on the other side. If its not lit, then the power from the utility is not there.
View attachment 237144
30amp Generlink cord set
View attachment 237145

For larger service
I too have 400amp service at a central farm distribution point. It was easier and cheaper to have my utility put in a special hook-up. Transconnect unit. Similar to the generlink, a special collar moves the meter out about 4 inches. It then has a special pigtail which connects another box. The other box has all the automatic transfer and disconnect circuitry. I have a full power plug (dual modular anderson 350amp gray with 2/0 pins) The same which is on the pto generator. see below

View attachment 237146 View attachment 237147
View attachment 237148 View attachment 237149

This really works well for me. I have feeds going out from here to the shop, run-in shed, barn, and large house. Each with there own panels.:thumbsup:

Thanks for the clarification. Good to know.

 

[daybreak1998]

The tombstone was installed by the power company. The transformer is just behind it. This is where they put the meters. The tombstone has two sides. One is locked and sealed. There is the total power consumption meter. From there are wires to the switch on the "user" side. On the "user" side is also meter for heating.
At this point there is nothing connected to the AUX. The neutral lugs (on the bottom in the middle) look like (in the picture) connected to the AUX terminals but they are not. The picture shows the switch before I connected the wires for the shop.

Howdy,
That unit looks really nice for a new installation. I too would suggest that anyone with a new installation look into having a meter with switch like this, or a panel with gen lockout kit. Like anything, it is a lot easier to start with these plans in mind, and build it that way. Coming back later, just involves so much more work and changes. I used a Milbank rural service meter panel outdoor 3r combo with generator lockout installed for a remote Ag well.

 

[timswi]

This is a typical rv system.. your transfer switch is in there somewhere,,It's totaly automatic as Airstream is very high end,,

I don't disagree with you although I have a Gulf Stream.

The point I was trying to make (not very well as it appears) is that some were trying to say that feeding the house was dangerous with a generator....I wasn't referring to the overheads, that's a whole other issue.

If Gulf Stream (more or less) backfeeds the coach with a run of the mill 5k Generac, then why is it dangerous to feed the house with a generator that is sized to the house useage?...Overheads out of the question, as mine won't power the other 4 houses...It'll die trying.

 

[hr3]

As a side note to backfeeding the house...I'm just curious as to why my motor home is factory built to backfeed the 5K generator back into the coach using the AC source cord with no transfer switch, just a closed circuit. If it's so dangerous to do that, why would Gulf Stream design it that way?

From what I have read about the Gulf Stream system it dosn't feed back it has a built in transfer between your shore power and the Gulf Stream generator.. If you walk into your trailer and turn a light on and it's not plugged into shore power the genny will start.. am I right on this ?? and if you walk in and turn on the same light and your plugged in the genny dosn't start,, " No Back Feeding involved"

I don't disagree with you although I have a Gulf Stream.

The point I was trying to make (not very well as it appears) is that some were trying to say that feeding the house was dangerous with a generator....I wasn't referring to the overheads, that's a whole other issue.

If Gulf Stream (more or less) backfeeds the coach with a run of the mill 5k Generac, then why is it dangerous to feed the house with a generator that is sized to the house useage?...Overheads out of the question, as mine won't power the other 4 houses...It'll die trying.

There is nothing wrong with feeding a house with a generator that is sized for the house and has the proper transfer switch installed..