Generator backfeeding into utility lines

[JDgreen227]

I was remembering this morning about someone who told me how he rigged up his generator to plug into his 240 volt dryer outlet, thus energizing his service panel without having the expense of a transfer switch. He claimed that by tripping the main breaker in his service panel, the danger to utility workers was completely eliminated while using his method.

That was a long time ago, and I have sometimes wondered if the method he used was as practical and as safe as he claimed it was. Can anyone here tell me if it would work as he described, and in addition, if you tried his method and left the main breaker on, how far could the current from a mid size generator....say 7000 watts output, carry with enough amperage to endanger someone working on the lines?

DISCLAIMER: I am in NO WAY suggesting I would try a generator hookup by this method, and am in NO WAY endorsing anyone else try such a hookup. Thanks.

 

[hawkeye08]

Technically if all the connections are broken back to the utility, it would be safe. Generally, only the hots are disconnected. I read about an add on bracket that used a breaker to the generator and the main breaker. Only one could be on at any given time.

 

[BethesdaEC]

It is completely safe, if you do it correctly, but I wouldn't recommend it and it is not legal. My dad and my uncle did something very similar except they did it with a dedicated breaker and power inlet. Two things can happen somebody turns on the inlet and you have a live male connector or somebody lights up a generator and does not turn off the mains. I have been trying to get them upgrade to an interlock kit because one day I am going to have to oversee their estates and that will never get past an inspection. An interlock kit does this but has a physical plate that prevents both breakers from being on at the same time. Incredible simple and way overpriced but worth every penny.

Generator InterLock Kit

 

[Mace Canute]

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.

 

[MikeD74T]

JD, Something else to think about. Linesmen don't rely solely on rules to keep them safe, they also connect substantial ground wires to sections they're working. These grounds have more than enough capacity to turn your generator into a one shot toaster should you accidentally improperly connect. MikeD74T

 

[JDgreen227]

JD, Something else to think about. Linesmen don't rely solely on rules to keep them safe, they also connect substantial ground wires to sections they're working. These grounds have more than enough capacity to turn your generator into a one shot toaster should you accidentally improperly connect. MikeD74T

Thanks, but I am sure I clearly stated I MYSELF have no intention of making such an unsafe, hazardous connection. Electricity scares me too much to attempt such a hookup. I had just remembered what someone told me a long time ago, after reading his funeral notice. No, he didn't pass away from an electrical shock....it was cancer.

 

[MikeD74T]

Thanks, but I am sure I clearly stated I MYSELF have no intention of making such an unsafe, hazardous connection. Electricity scares me too much to attempt such a hookup. I had just remembered what someone told me a long time ago, after reading his funeral notice. No, he didn't pass away from an electrical shock....it was cancer.

Wasn't trying to imply any potential wrong doing on your part. Your question has been asked & answered many times on TBN. A large portion of responses predict dire consequenses to linemen. In reality, although the open breaker protection is valid until human failure intercedes, the failure of a generator is more likely than injury to a lineman. This doesn't negate that injury to a lineman is far worse than death of a generator. MikeD74T

 

[BobRip]

There is a stiff fine and jail sentence for back feeding. Don't do it. Get the interlock bracket. I made one and it worked great. Last week I bought the commercial one. About 175 after shipping. Rediciously over priced, but I sleep better.

 

[whistlepig]

There is a lot of good information available about back feeding lines. Its easy to do. I was considering this when we bought our first portable generator. From all the information that I have read, mostly from the generator manufacturer and the electric companies, I decided not to back feed the house.

 

[Tractor Seabee]

The $175 cost also includes two 2 pole breakers probably. I had an emergency panel already in my emergrncy panel when I bought the place. It only had a 30 A Generator feed breaker. Last winter I upgraded to 17.5 KW Gen and upgraded it all to a 50 A gen breaker. I did a post elsewhere with all the details in how to do it. The danger to the linemen is that after the gen power hits the utility power it goes through a transformer which ups the voltage to probably 12470 V, the normal utility distribution voltage. Yes the linemen ground what they are working on but they are human too. You would not want to be around if they forget to remove the grounding straps (I have). The big box stores have the kits for all the brands of breakers they handle. Remember you have to have a seperate panel for the circuits you want to power with the Generator as the kit is not available for the panel main breakers. You would need a manual transfer switch rated at the utility power supply or an automatic transfer switch. You can buy a small panel and a bunch of breakers for less than 1/2 the price of a 200A manual transfer switch. Autos are reserved for whole house generator systems and are really spendy. The genset has to be set up for remote start.

 

[JB4310]

There is a stiff fine and jail sentence for back feeding. Don't do it. Get the interlock bracket. I made one and it worked great. Last week I bought the commercial one. About 175 after shipping. Rediciously over priced, but I sleep better.

You mean backfeeding the utility lines? cause I can't see how back feeding your own house, by what ever means could be illegal.

I think those interlock things are the greatest idea since sliced bread. $175. does seem high for a bent piece of sheet metal and 2 screws. There is no great engineering to it, someone else made his own and it worked just fine.
I would have one myself except I have no main in my panel. My panel is so many feet away from the service entrance that it required the main to be outside at the entrance. I'm not sure if I could of had another 200 amp breaker inside as well, but the electrician who did the upgrade didn't put it in

So for now I have to rely on memory if I need to backfeed the house, until I get a 200 amp double pole/throw switch. First of all though, we never lose power, I was actually hoping we would lose power during hurricane Irene just so I could go through a live drill. Second, when you look at a 50 amp 220 volt male/male cord jumper, it is very sobering, it will scare you, and help jog your memory.

JB

 

[kco]

Backfeeding is a greater risk for the public. In our area it is not uncommon for trees to tear down power lines. The utility company's breakers trip to isolate the fault and linemen know how to protect themselves. The general public may assume a downed line is safe because they can see a blown fuse.

There is the possibility that a person may try to move what he assumes is a de-energized conductor from a road. I encountered this exact situation on our road last year. (being an ex-linenman I can't resist patrolling the line when our power goes out). A span was down across the road at the end of a neighbour's driveway. The neighbour and his wife were also looking at it. The fuse about a mile away had blown, but I told him not to go near either broken conductor since someone could backfeed with a generator (there are about 20 homes on the tap feeding our road).

I imagine many people don't recognize the hazard of someone other than the power company energizing a line.

 

[beppington]

With more & more solar system installations, residential generators, & a faltering economy resulting in more shortcuts being taken, it seems to me that linemen should just go ahead & assume at all times that "mistakes" have been made & that many folks are illegally backfeeding the power lines at all times, i.e. assume that they are always hot.

Maybe they already do this ... ?

 

[boggen]

With more & more solar system installations, residential generators, & a faltering economy resulting in more shortcuts being taken, it seems to me that linemen should just go ahead & assume at all times that "mistakes" have been made & that many folks are illegally backfeeding the power lines at all times, i.e. assume that they are always hot.

Maybe they already do this ... ?

i do not think mistakes have been made, but rather, the lines have power regardless in them.

on grid, tie ins, were solar panels, to wind turbines are hooked up. there could be plenty of homes were they sell energy back to the electric co. and be pumping energy back into the grid. and the meter that lets this happens. may not be setup or electronic enough to shut that power off feed back into the grid. when the main grid goes down.

 

[hayden]

i do not think mistakes have been made, but rather, the lines have power regardless in them.

on grid, tie ins, were solar panels, to wind turbines are hooked up. there could be plenty of homes were they sell energy back to the electric co. and be pumping energy back into the grid. and the meter that lets this happens. may not be setup or electronic enough to shut that power off feed back into the grid. when the main grid goes down.

There is a UL spec that any grid-tied solar/wind etc inverter has to meet, and they are tested and confirmed to meet the spec. It ensures they can't backfeed when the grid is down. You can't buy an inverter that doesn't meet the spec. All utilities require the UL certification before you inter tie. It's a non issue.

Another thing to keep in mind with a generator attempting to back feed the grid is that the grid is NOT an open circuit. If you attempt to backfeed, your generator will be attempting to power your neighborhood, and everything between you and where ever the line/failure occurred. Your generator will lose that battle and stall or trip it's breaker. Don't ask me how I know

The only case where you will energize a power line is if it's connected to your house and pretty much nothing else - in other words if the break is between you and all the other houses' loads.

But, just to be clear, I'm not advocating back feeding. An interlocking breaker or a double pole double throw breaker is the correct way to attach a generator.

 

[BobRip]

The $175 was just for the bracket. You may find a better price.

Back feeding is sending power out of your house to the power lines.

You can power up your house legally. Just do it the right way.

 

[hayden]

The $175 was just for the bracket. You may find a better price.

It's certainly expensive for a bracket, but much cheaper than a 200A DPDT switch/breaker which can run $1000 or more. So I guess in comparison it's a bargain.

 

[BobRip]

It's certainly expensive for a bracket, but much cheaper than a 200A DPDT switch/breaker which can run $1000 or more. So I guess in comparison it's a bargain.

Exactly

 

[aczlan]

It's certainly expensive for a bracket, but much cheaper than a 200A DPDT switch/breaker which can run $1000 or more. So I guess in comparison it's a bargain.

It is probably also UL listed, so your insurance company cannot use it as a reason to deny coverage if something happens.
EDIT: ('it' being a UL listed interlock vs a home made one)

Aaron Z

 

[hayden]

It is probably also UL listed, so your insurance company cannot use it as a reason to deny coverage if something happens.
Aaron Z

At the risk of taking this off on a tangent....

I've never read anything in my homeowner's policy that says coverage only applies if things are UL listed. Has anyone seen such language in an insurance policy?