Electricians, generator hookup advice needed

Electricians, generator hookup advice needed

PostBy: g350h On: Wed Sep 07, 2011 11:55 am

I know a few people that when they lose power they turn off there main breaker, and back feed the panel by hooking a generator to the clothes dryer plug, 220. Is this safe? Would that make all the outlets 220? I don't mess around with electricity, just wanted to know of a safe way next time I lose power.
g350h
 
Hot Air Coal Stoker Stove: Alaska/w homemade air jacket

Re: Electrians,generator hookup advice needed

PostBy: Dann757 On: Wed Sep 07, 2011 12:14 pm

I'm no expert, take no advice from me. That's an interesting idea, no it wouldn't make all the outlets 220. It would feed 110 to each hot leg of the receptacle and back to the panel. Most dryers are 30 amp plugs I think. So if you happened to be running a lot of electrical loads while taking your generator power in through your dryer circuit, I don't know what would happen if your load exceeded the rating of the circuit. I don't know if it would trip the dryer breaker on the panel if it needed to. It is A.C., but your hot legs would be on the wrong side of the breaker, feeding power back through the breaker to the two hot buss bars!
Also, if for some bizarre reason, somebody went to disconnect the dryer wires from the breaker, usually after switching it off, they would be confronted with hot wires where they expected ones that were off!
Somebody here might know more.

During the chaotic emergency of Irene, I hooked a 30 amp 220 extension cord to the panel like this. ( I already bragged about it in another threaed...)The main breaker is in its own box outside next to the meter. When I cut the main 200a breaker, I put a LOCK on that box! Male end went into the generator receptacle. Had to cut off the female end, after the storm everybody sold out of L1430 plugs! It worked very well for the emergency. Now if I wanted to leave the extension cord ready, I would have to put the male plug into a dummy female plug and keep it there with a big ole warning label, because the male legs would be hot as soon as the main breaker is turned on! Or wire it to a dedicated power shutoff switch. However, if that switch was inadvertently left on, the male plug of the cord would still be hot and hazardous as hell. I'm sure they have automatic transfer switches and even manual lockout plates that can be worked in to the setup. I already took out all that emergency wiring I did and put everything back the way it was.
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Re: Electrians,generator hookup advice needed

PostBy: Wood'nCoal On: Wed Sep 07, 2011 1:03 pm

The proper method is with a manual transfer switch.
Circuit breakers are designed and evaluated for use when "Line" and "Load" are connected to specific terminals. Most GFI breakers will be destroyed when backfed.
Specific circuit breakers are made for safe current flow in both directions, such as found when the home has solar panels installed.
Backfeeding through any installed wiring in the home is a mistake because the line from the receptacle where the generator is connected back to the panel is not protected by a circuit breaker. If the load exceeds the wire's capacity the wire can overheat and cause a fire.
A manual transfer switch also isolates the neutral.
http://www.cumminspower.com/www/literat ... C-2-en.pdf

http://www.wagnerequipment.com/PowerSystems/Consultants_Corner/Switching_The_Neutral.pdf
This link is broken, either the page no longer exists or there is some other issue like a typo.


Basically if you don't know what your doing---don't do it!

Hope this helps!
Wood'nCoal
 
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Re: Electricians, generator hookup advice needed

PostBy: Freddy On: Wed Sep 07, 2011 1:27 pm

I guess in one breath I'd say: It can be done safely, but if you AND another adult living under that roof do not understand how to connect & disconnect it, I HIGHLY recommend a professional install a transfer switch. Yes, they seem expensive, but how much is a funeral?
Freddy
 
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Re: Electricians, generator hookup advice needed

PostBy: AA130FIREMAN On: Wed Sep 07, 2011 1:48 pm

The most important thing is to turn OFF the main breaker coming in from the grid if you backfeed from a dryer recptacle, or you will supply power to the grid and potentially have a funeral for the lineman that may be working on the grid.
AA130FIREMAN
 
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Re: Electricians, generator hookup advice needed

PostBy: Dann757 On: Wed Sep 07, 2011 1:58 pm

AA130FIREMAN wrote:The most important thing is to turn OFF the main breaker coming in from the grid if you backfeed from a dryer recptacle, or you will supply power to the grid and potentially have a funeral for the lineman that may be working on the grid.


That raises an important question for myself, after looking through John's articles, I realize that the way I hooked up our generator did not isolate it completely from the street. The neutral leg was still continous to the street. To really isolate the generator, I should have disconnected the neutral leg at the panel.

I did make sure no hot leg could possibly feed back by putting that lock on, main breaker off, but now I'm wondering about the neutral. The neutral is also grounded to the physical ground at the main box, so if I disconnected the neutral leg at the panel, I might have lost ground! Gotta take a closer look, and next time take off for Maine....

EDIT: I just checked the whole situation, the panel is grounded separately out to the neutral, and from there to the ground stake.
Last edited by Dann757 on Wed Sep 07, 2011 2:16 pm, edited 1 time in total.
Dann757
 

Re: Electricians, generator hookup advice needed

PostBy: Wood'nCoal On: Wed Sep 07, 2011 2:04 pm

I guess I have to say it again, it can be done, but it cannot be done safely.

Electric dryer outlets are typically #10/3 wire. Depending on the type of insulation that wire can be rated for30/35/40 amps. If you have a generator capable of producing 40 continuous amps and wire rated for 30 amps then guess what?

Backfeeding through any installed wiring in the home is a mistake because the line from the receptacle where the generator is connected back to the panel is not protected by a circuit breaker


I'm sure most people have a portable generator that won't produce that much current but I'm sure there are exceptions.

http://en.wikipedia.org/wiki/American_wire_gauge

The neutral leg was still continous to the street. To really isolate the generator, I should have disconnected the neutral leg at the panel.


It looks like isolating the neutral has to do with GFI circuits and protection.

A friend of mine asked his electrician friend about backfeeding and neutral isolation and his reply was to make sure to shut off the main breaker. :roll: :o
Wood'nCoal
 
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert

Re: Electricians, generator hookup advice needed

PostBy: grumpy On: Wed Sep 07, 2011 3:08 pm

Here's my set up, no neutral kit in this switch..
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Re: Electricians, generator hookup advice needed

PostBy: coal berner On: Wed Sep 07, 2011 3:23 pm

Dann757 wrote:
AA130FIREMAN wrote:The most important thing is to turn OFF the main breaker coming in from the grid if you backfeed from a dryer receptacle, or you will supply power to the grid and potentially have a funeral for the lineman that may be working on the grid.


That raises an important question for myself, after looking through John's articles, I realize that the way I hooked up our generator did not isolate it completely from the street. The neutral leg was still continues to the street. To really isolate the generator, I should have disconnected the neutral leg at the panel.

I did make sure no hot leg could possibly feed back by putting that lock on, main breaker off, but now I'm wondering about the neutral. The neutral is also grounded to the physical ground at the main box, so if I disconnected the neutral leg at the panel, I might have lost ground! Gotta take a closer look, and next time take off for Maine....

EDIT: I just checked the whole situation, the panel is grounded separately out to the neutral, and from there to the ground stake.

You also need to ground the Gen that's there are grounding post on the Gen stick a grounding rod in ground the Gen to it
coal berner
 
Stoker Coal Boiler: 1986 Electric Furnace Man 520 DF
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Re: Electricians, generator hookup advice needed

PostBy: Freddy On: Wed Sep 07, 2011 3:25 pm

Even a transfer switch does not break the neutral.
Freddy
 
Stoker Coal Boiler: Axeman Anderson 130 (pea)
Hot Air Coal Stoker Stove: Reading piece o' junk in the barn (rice)
Coal Size/Type: Pea size, Superior, deep mined

Re: Electricians, generator hookup advice needed

PostBy: Dann757 On: Wed Sep 07, 2011 3:41 pm

Freddy wrote:Even a transfer switch does not break the neutral.


Glad to hear that :!: I guess with the right switch you can if you want to. John's articles had a lot to do with GFI devices.

Cool setup Grumpy! The coal ash on your ammeters looks exactly like the coal ash on my TV. :lol:
Dann757
 

Re: Electricians, generator hookup advice needed

PostBy: jpete On: Wed Sep 07, 2011 3:54 pm

I did it to both my house and my in laws after the storm. The most important point is shutting the main off.

My generator has breakers on it at all the outlets. My 240V outlet is 20A and my dryer is 30A so I wasn't all that concerned about the breaker in the house. If I drew too much, it would trip the generator breaker first.

I used 4' of 8/3 wire between the generator and the dryer outlet so I had plenty of capacity there.

The other point is the GFI outlets. I don't have any in my house nor do my in laws but a friend does and he blew one out back feeding his welder outlet in his garage. And they fail spectacularly so if there is anything flammable nearby, you'll be in a world of hurt.

It certainly isn't right, and it might not even be legal, but in a pinch, it CAN work if done correctly. A transfer switch and generator socket is the "right" way to do it though.
jpete
 
Hand Fed Coal Stove: Harman Mk II
Coal Size/Type: Stove, Nut, Pea
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Re: Electricians, generator hookup advice needed

PostBy: grumpy On: Wed Sep 07, 2011 4:16 pm

You need a switch or some other way to make it either or, if not you are not legel in most places. Remember that, the consequences could be severe, just saying.

Besides, it really is fun to pull the big red switch and hear it go clunk.... :D
grumpy
 

Re: Electricians, generator hookup advice needed

PostBy: WNY On: Wed Sep 07, 2011 5:55 pm

This is similiar to the one I have, with an outside plug for the generator. At least I haven't had to use it, yet.

http://www.amazon.com/gp/product/B000BQ ... B000BQN4T2
WNY
 
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Re: Electricians, generator hookup advice needed

PostBy: 009to090 On: Wed Sep 07, 2011 6:14 pm

I feed my genertor into a dedicated 30 amp 240vac circuit breaker in the Main Panel. I have an InterLock, so I cannot have the Generator's Circuit Breaker and the Main Breaker both on at the same time.
Neutral feeds to gtround, eventually. No Need for seperate shut off for it.

Grumpy, nice switch. Looks like you could switch off New York City. How many Amps is that rated for?
009to090
 
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