Generator and electricity flow

[sdkubota]

The issue is the wire in the wall, which is sized for the service breaker, but which is being driven by the generator over its capacity, by appliances on the same circuit. Because the appliances are on the same circuit as the genny, there is no current flow through the breaker, and the wire is unprotected, except by the genny's breaker which is too large.

Winner, winner, chicken dinner.:thumbsup:

 

[Ken45101]

The issue is the wire in the wall, which is sized for the service breaker, but which is being driven by the generator over its capacity, by appliances on the same circuit. Because the appliances are on the same circuit as the genny, there is no current flow through the breaker, and the wire is unprotected, except by the genny's breaker which is too large.

You have a good point. It would be wrong and dangerous (fire wise) to backfeed a (house) branch circuit with anything more than a 2000 watt generator (or from a generator outlet with more than a 20a breaker on it.) Even then one should make sure they are feeding a 20a rated house outlet.

I'll admit that I don't have much experience with a wide range of generators but all that I have seen only have 15 or 20 amp outlets for 110v. Beyond that, you need to go to a heavier rated 220v outlet and 220v connection which is not what you can feed a typical house branch circuit. Hopefully anyone feeding their house via such a generator connection realizes that they need special wiring and hookup if they want more than 110v 20 amp service or they need the proper wiring and plug to feed a range or dryer outlet.

Bottom line, if you want more than 110v 20 amp (2000 watts), you really need to get a proper connection into your breaker box.

 

[bdeboer]

I'm interested in installing a safe and approved method of plugging my portable generator into my house.
All of the schemes and transfer switches I've found seem to require that I have room for additional breakers.
It looks like all my spaces have been used up. Is there a simple solution for me or do I have to buy a new house?



Thanks for any advice.

View attachment 296419

We have the generlink referenced above, it was installed by our local electrical co-op. They unplugged the meter installed the generlink and replaced the meter. No wiring or breakers were changed. Your panel also has a rating for the number of circuits which may be exceeded if double circuits up, just another spec. to be aware of.

GenerLink.com - About GenerLink - The easy way to connect a home generator

Through the Co-op they installed it for about the same as the online pricing I found.

 

[SlowPocono]

That Generlink device looks pretty slick but If I'm not mistaken it costs about $700.00.
That's a little too nice for me.

 

[Ken45101]

We have the generlink referenced above, it was installed by our local electrical co-op. They unplugged the meter installed the generlink and replaced the meter. No wiring or breakers were changed. Your panel also has a rating for the number of circuits which may be exceeded if double circuits up, just another spec. to be aware of.

GenerLink.com - About GenerLink - The easy way to connect a home generator

Through the Co-op they installed it for about the same as the online pricing I found.

That sounded really good.....until I saw the $700 price! I think I'll stick to running extension cords to the few things that really need power.

But thanks for passing along another idea.

Ken

 

[joshuabardwell]

You have a good point. It would be wrong and dangerous (fire wise) to backfeed a (house) branch circuit with anything more than a 2000 watt generator (or from a generator outlet with more than a 20a breaker on it.) Even then one should make sure they are feeding a 20a rated house outlet.

They say a little knowledge is a dangerous thing. I think we're firmly in that territory now. Assuming that you're backfeeding via a 110v receptacle, which would only feed half the circuits in the house, by the way, you would want to make sure that your supply current was less than the breaker on the circuit you're backfeeding, since the wire on that circuit will have been sized to match the breaker. You say a 2000W genny, but bear in mind that most generators are 240v, and will have two separate 120v legs, each carrying half the generator's rated wattage. So assuming a 20A breaker on a 120v circuit (equals 2400W), you could have up to a 4800W generator without overloading the wiring.

I'll admit that I don't have much experience with a wide range of generators but all that I have seen only have 15 or 20 amp outlets for 110v.

That's my experience too. Standard 120v receptacles are almost always rated for 10 or 15 amps. The 20-amp receptacles have one of the prongs at a right angle, as shown here:

So even if the generator was more than 4800W, it probably won't be putting more than 15 or 20 amps on a single 120v leg. BTW, there is a 30-amp 120v plug and receptacle, but you hardly ever see them.

Beyond that, you need to go to a heavier rated 220v outlet and 220v connection which is not what you can feed a typical house branch circuit. Hopefully anyone feeding their house via such a generator connection realizes that they need special wiring and hookup if they want more than 110v 20 amp service or they need the proper wiring and plug to feed a range or dryer outlet.

No. Hopefully anyone feeding their house this way realizes that the whole idea of backfeeding via a suicide cord is dumb and dangerous and they will think better of it. The reasons we have laid out here are just some of the things that can go wrong. There are many more. If the power is out and your sainted grandmother needs her dialysis machine to live, and the only way to run it is to backfeed, then it might be worth it. But really, you should plan ahead for these things and get an interlock or transfer switch and do it right.

Bottom line, if you want more than 110v 20 amp (2000 watts), you really need to get a proper connection into your breaker box.

Bottom line: you really need to get a proper connection into your breaker box, PERIOD.

 

[bdeboer]

That Generlink device looks pretty slick but If I'm not mistaken it costs about $700.00.
That's a little too nice for me.

I figured $700 or $600 (2 years ago) would be gone quickly when I started looking at other options like moving ciruits etc.

 

[joshuabardwell]

I figured $700 or $600 (2 years ago) would be gone quickly when I started looking at other options like moving ciruits etc.

IMO, backflow breaker with interlock kit is the cheapest and most versatile option. About $200 for the interlock kit, and whatever a new breaker costs you. If your service panel is full, then you have some additional cost to buy half-width breakers and some hassle of re-wiring the panel to incorporate them, but overall, you'll come out way cheaper than a transfer switch and you can power whichever circuits you want, instead of having to pre-select a few.

 

[SlowPocono]

The Generlink device allows all circuits to be available as well. For me, the expense is the issue.
I've ordered a genuine Square D interlock kit for $79. That seems sensible to me.
I still need to buy a few breakers but The total cost will be bearable.

 

[radioman]

I'm interested in installing a safe and approved method of plugging my portable generator into my house.
All of the schemes and transfer switches I've found seem to require that I have room for additional breakers.
It looks like all my spaces have been used up. Is there a simple solution for me or do I have to buy a new house?



Thanks for any advice.

View attachment 296419

If you get a new subpanel for the generator that has saftey interlock - you will be freeing up space in your old panel from whatever circuits you pick. all the black wires needs to be "moved" over to new subpanel. You can just pull out the old breakers for the new transfer switch breaker. If you have other breakers to pull- but no safety plug to back in the door to cover hole - leave them in until you get blanks. Its not safe or to code to have a empty slot and metal slots removed.