Generator for home without a transfer switch

Dench

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Why no transfer or interlock? I had an interlock put in. Not a hard install and my entire house can be run. An extension cord is going to really, really suck when it's either a blizzard/ice storm/hurricane/wind/rain and you have to run long cords into your home with weather that will be trying to get in, and heat that will be getting out.
 

joe847

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More likely to kill your gennie than a lineman, takes a lot of juice to backfeed those lines. But yeah I wouldn’t want to be one of those guys. Gens and solar everywhere these days... Like above I only recommend backfeeding a spare if you install an interlock. You might remember to do things in order when you test it once a year...I mean month. But @2AM on a Tuesday just you, your britches and a flashlight...forgetting is very easy.
It does not take a lot of "juice" to backfeed those lines. The smallest generator that you can find will have no trouble producing the tiny amount of amperage need to seriously injure or kill a human.

I support the "it's your house do whatever you want" philosophy but once you start sending electrons flowing outside your property you own whatever they do.
 

Robin Proctor

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It does not take a lot of "juice" to backfeed those lines. The smallest generator that you can find will have no trouble producing the tiny amount of amperage need to seriously injure or kill a human.

I support the "it's your house do whatever you want" philosophy but once you start sending electrons flowing outside your property you own whatever they do.

ahh that’s a negative ghost rider. Gens primally produce voltage, with out a load to feed no current comes out. the more voltage needed and the more resistance it needs to overcome the less load(current it can serve) When you run into large resistance like extremely large lines and transformers. The Gen tries to provide the voltage it is rated at , to over come the resistance, and that’s where current comes in. You see this if you plug in a really long and small gauged extension cord to your generator. The voltage at the end of it will be slightly less than the voltage at the beginning of it. It’s called voltage drop. Instead of your one long extension cord it’s trying to provide rated voltage to thousands and thousands of extensions cords”lines” and energize transformers to put the voltage up to rated line voltage. So you wind up with needing more than your little gen can provide. I summarized this explanation as “juice” above.

My profession is electrical testing. I do this type of thing all the time. If you have a large Cogen, like hospitals and manufacturing facilities do then yes you can back feed the lines with hazardous voltages. But those cogens are usually putting out at the line voltage or are transformed up to line voltage before exiting the facility. Your 120/208 gen is in most cases going to hit a single pole transformer right out in front of your house and then have a failure as soon as the voltage tries to energize the lines. The current will rise rapidly as the voltage drops rapidly and best case your circuit breaker trips worst case you need a new generator.....I still advocate for an interlock 100% of the time between your gen and your main because if the sources go head to head then you will at best case have a tripped breaker or at worse case have a fire in your house.
 
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AHM

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ahh that’s a negative ghost rider. <snip>
You could have just told him that his 10KW Radio Flyer home generator
is going to pop its breaker when it tries to power every single refrigerator
in every single house that lost power in the neighborhood.

We lost power from some subtle failure(*) on Saturday night,
and that would have been 95 refrigerators
(assuming no one had a beer reefer in the garage,
or any light fixtures or well pumps that needed electric love).

Which may still send a pulse that stops the heart
of some lineman gnawing the insulation off of a
wire he's about to splice. But let that go.

Or maybe it even pops the 200A house breaker. Who knows?

(*) Half an hour after the failure, a cherry picker drove up the street
right past the first house without power, and then U-turned
at the end of the line and drove back past us. So the failure wasn't
a 300-yo oak tree across the road, or some drunk plowed into an electric pole.
But he got 'er done in a hair over two hours.
 

appraiser

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not to hi-jack... but

I recently picked up a generator too.
Need to find a pro to wire it for me - household electrical is one of those things I never picked up.

Any contractors/electricians on here, please feel free to PM me.
I've got more projects too (i.e. room above garage, run 220 to garage)
Palladin is your man

He is going to put a new panel with an interlock in my Mom's house this summer when I get back from Florida.
 

Robin Proctor

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You could have just told him that his 10KW Radio Flyer home generator
is going to pop its breaker when it tries to power every single refrigerator
in every single house that lost power in the neighborhood.

We lost power from some subtle failure(*) on Saturday night,
and that would have been 95 refrigerators
(assuming no one had a beer reefer in the garage,
or any light fixtures or well pumps that needed electric love).

Which may still send a pulse that stops the heart
of some lineman gnawing the insulation off of a
wire he's about to splice. But let that go.

Or maybe it even pops the 200A house breaker. Who knows?

(*) Half an hour after the failure, a cherry picker drove up the street
right past the first house without power, and then U-turned
at the end of the line and drove back past us. So the failure wasn't
a 300-yo oak tree across the road, or some drunk plowed into an electric pole.
But he got 'er done in a hair over two hours.

you said it better in one sentence then I did in 2 paragraphs.
 

xjma99

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Listen to @Palladin to do it right.

Many people do backfeed through a 30amp twistlock connection. Code says if you do this you have to have an interlock and also break the bond between neutral and ground at the panel. Virtually no one back feeding does this. Some do not wire the ground wire on the 30amp receptical so that if your generator is chassis bonded neutral, then there aren’t two neutral - ground bonds.

Short answer is backfeeding is fairly common just buy that little interlock for your panel to make it dummy proof.

And like everyone said, the load regulation of a generator suffers greatly near its max rating. Two common reasons generators cause issues for downstream equipment:
1) Running at max load and surging causes voltage and frequency variation.
2) Running out of gas and wild surging causing wild voltage and frequency variations.

Both of these get better if you run your gen at ~50% rated load. You have better economy and you also have much better voltage/frequency regulation
Cite code article where you have to open the neutral when running a home on a portable generator, or even a permanently installed automatic backup generator.

I’ll give you a hint, neither of these qualify as a ‘separately derived system’.
 

Palladin

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Cite code article where you have to open the neutral when running a home on a portable generator, or even a permanently installed automatic backup generator.

I’ll give you a hint, neither of these qualify as a ‘separately derived system’.
Doesn't exist. Don't need to switch the neutral as a home generator isn't a separately derived system
 

mac1911

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Hi there we are looking for a generator for our house

We would use for the generator for the following:
sump pump
Furnace (gas)
Tankless water heater (gas)
Coffee maker (not a deal breaker could also do the whole French press deal v keurig)
Fridge
Maybe the tv etc and some lights
Portable heater (dyson)
Washer dryer are electric but wouldn’t plan to run

We don’t have a transfer switch so would just run extension cords.

Thinking of this one thoughts?

Get a transfer switch they are not all that expensive use your extension cord money as a down payment
 

mcb

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The interlock kit itself is an extra $50. Why skinflint on that? You can also throw a power return alarm for another $50 the ultimate in manual generator luxury.
 

RHJJ

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If the op wants to go with extension cords,the only issue would be the furnace. For that they make a UL approved three position switch / box that the female end of elec cord plugs into. You would want an electrician to install that for you.
Take that money and do it right with an interlock.
 

Atlantis

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Sorry if I came off like a certified electrician. I’m just a guy who reads a bit.

Help me out here to clarify my understanding. Perhaps what I am referring to is whichever part of the code says you can’t have more than one neutral-ground bond. I.e. not bonding a sub panel, etc.

So if I have a transfer switch installed, and I have a chassis bonded generator with a ground rod, I would have two ground-neutral bonds. Is this okay per code? If not, what is required to become compliant?
 

Palladin

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Sorry if I came off like a certified electrician. I’m just a guy who reads a bit.

Help me out here to clarify my understanding. Perhaps what I am referring to is whichever part of the code says you can’t have more than one neutral-ground bond. I.e. not bonding a sub panel, etc.

So if I have a transfer switch installed, and I have a chassis bonded generator with a ground rod, I would have two ground-neutral bonds. Is this okay per code? If not, what is required to become compliant?
No, the bond between the neutral and ground on a portable generator should be removed. In my experience, only Westinghouse bonds all generator mounted devices. All others, so far, only bond the 120v receptacles so the GFCIs will function. The 240v receptacle isn't, which allows for it's transfer function.

You only need a ground rod with a generator if you were setting it up as a separately derived system. Meaning you were in the middle of nowhere and we're using it for primary power to a house panel which did not have a utility connection
 

Rob Boudrie

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Listen to @Palladin to do it right.

Many people do backfeed through a 30amp twistlock connection. Code says if you do this you have to have an interlock and also break the bond between neutral and ground at the panel. Virtually no one back feeding does this. Some do not wire the ground wire on the 30amp receptical so that if your generator is chassis bonded neutral, then there aren’t two neutral - ground bonds.

Short answer is backfeeding is fairly common just buy that little interlock for your panel to make it dummy proof.

And like everyone said, the load regulation of a generator suffers greatly near its max rating. Two common reasons generators cause issues for downstream equipment:
1) Running at max load and surging causes voltage and frequency variation.
2) Running out of gas and wild surging causing wild voltage and frequency variations.

Both of these get better if you run your gen at ~50% rated load. You have better economy and you also have much better voltage/frequency regulation
Some generators are neutral-ground bonded. Some of these make it easy to remove the ground so you use only the bond in the house on a backfeed.

Some (like at least some Hondas) are not neutral-grounded bonded, so you just backfeed them and there is still only ground/neutral connection.
 

DPR

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Powering your furnace or fridge (or other appliances) might be an issue on a portable generator. I would review this with whoever does the install. I would also test run the generator to confirm it powers what you need.
 
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Cite code article where you have to open the neutral when running a home on a portable generator, or even a permanently installed automatic backup generator.

I’ll give you a hint, neither of these qualify as a ‘separately derived system’.
This. Why would u ever separate neutral and grounding at a residential service?...not good.
 

Palladin

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Powering your furnace or fridge (or other appliances) be an issue on a portable generator. I would review this with whoever does the install. I would also test run the generator to confirm it powers what you need.
I always test out an installation AND give detailed instructions and run the homeowner thru the entire process of hooking up their generator. After 260 installs, I kinda know what I'm doing
 

Atlantis

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This. Why would u ever separate neutral and grounding at a residential service?...not good.

If you happen to be installing as an SDS that is bonded at the source, I believe code would require it...

Also either the transfer switch is separating, because the B source is already bonded, or as I mentioned, some folks just prefer to not connect the ground from the generator to the ground in the Receptacle being back fed. I guess this is about the same as a dryer plug. Only most new generators have a 4 prong twist lock. So some people advocate not connecting the ground of the generator to that twist lock receptacle.
 

DPR

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I always test out an installation AND give detailed instructions and run the homeowner thru the entire process of hooking up their generator. After 260 installs, I kinda know what I'm doing
That's nice. I was only pointing out to the OP that a newer appliance/furnace might not operate off his portable generator.
 

xjma99

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If you happen to be installing as an SDS that is bonded at the source, I believe code would require it...

Also either the transfer switch is separating, because the B source is already bonded, or as I mentioned, some folks just prefer to not connect the ground from the generator to the ground in the Receptacle being back fed. I guess this is about the same as a dryer plug. Only most new generators have a 4 prong twist lock. So some people advocate not connecting the ground of the generator to that twist lock receptacle.
That’s a hack to make a generator designed to be used as a job site generator with ground fault protection work to backfeed a house panel. Neutral and ground can only be bonded at one spot.
 

AHM

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you said it better in one sentence then I did in 2 paragraphs.
Thank you for generously surmounting my vibes.[bow]
And I wouldn't have jumped up without you addressing the subtopic...

FWIW, I'm braining from general principles - not an authoritative source.
I stand ready to be korected by a cardiologist or a master electrician.

And it took me decades to perceive that One Weird Consequence
of backfeeding a neighborhood -
it didn't jump up and bite me as soon as I heard of the risk.


Just to really give you pause about where all this sage advice is coming from,
I may be the most recent NESer to pop a breaker.[shocked]

Or at least to admit it.[rolleyes]

A few months ago, I was replacing our 1984 dining room chandelier
without turning off the branch -
I don't have every single load detail mapped on the breaker panel,
and I didn't want to be resetting all the digital clocks.

While messing around in the ceiling junction box,
some hot wire that I could have sworn was gonna be switched off
got away from me, went sproing and briefly bounced off of the box
or another connector or something.

POP!

Trudge to the basement.
Quite possibly the first Breaker Pop since we bought the house in '86.

Glad I didn't nuke the new wall switch with leetle Mood Lighting slidy pot.

When I had everything assembled and working,
I discovered a teentsy BB next to my keyboard.
It was a briefly molten sphere of copper.[shocked]
Very glad I didn't put that in my eye.😜

These incidents run in the family. (Stanza #3).
 
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If you happen to be installing as an SDS that is bonded at the source, I believe code would require it...

Also either the transfer switch is separating, because the B source is already bonded, or as I mentioned, some folks just prefer to not connect the ground from the generator to the ground in the Receptacle being back fed. I guess this is about the same as a dryer plug. Only most new generators have a 4 prong twist lock. So some people advocate not connecting the ground of the generator to that twist lock receptacle.
This is not a separately derived system issue, this is a portable generator being hooked up in a single-family dwelling. In a single-family dwelling when you start separating your grounded from your grounding u are Temting fate for some very serious hazards.
 

teamRR

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For temporary use you can just get a generator that meets your needs and budget, shut the main and back feed via a dryer or oven 240 circuit. Then you can use anything in the house that your generator can power.

I got by for years in a place where I lost power once a month via a 5000 watt husky. Was so frequent the generator lived on the deck with the backfeed cord permanently run into the basement, up and running in a couple minutes. Well pump, electric water heater, AC's, all that..

In short if you go that small you need to use your brain. I would shut the water heater off until hot water was needed for the shower and would then shut off anything high draw if the pump and water heater were going to be run. About 1000 hours on that generator and never had an issue. Generally speaking it powered the whole house just you had to be careful about using multiple big power suckers at the same time, far less of an issue if you don't have a well pump.
 
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