I know its wrong (BACK FEED GENERATOR)

Reply

  #1  
Old 09-07-04, 08:03 PM
stanstuf
Visiting Guest
Posts: n/a
I know its wrong (BACK FEED GENERATOR)

I know back feeding generator current has it's unsafe circumstances but I would like some imput if you will.I have a subfeed in my garage that controls the west side of my home which has all the items needed to substain comfort in case of a power outage .There is a main breaker that isolates this subfeed from the main panel and all incoming utilities.The subfeed has a 220 double throw breaker that connects to a dryer.Here is my ouestion,-If I plug my 8kw generator into my dryer outlet ,switch off the main imput breaker from the main panel to the sub feed,and select the breakers that I want to make hot and not exceed a safe total wattage or amps ,is there any major problem?
 
Sponsored Links
  #2  
Old 09-07-04, 08:13 PM
HandyRon's Avatar
Member
Join Date: Dec 2001
Location: New York
Posts: 1,365
What size wire and circuit breaker is on the dryer circuit?
 
  #3  
Old 09-07-04, 08:43 PM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,930
Upvotes Received: 5
Don't do it!

You cannot guarantee that there would not be any leakage to the outside line or that someone other than yourself would throw an incorrect switch and hurt or even kill an unsuspecting utility worker.
Your sustaining comfort in an emergency situation does not warrant the potential risk to others outside your home.

I suffer occasional power outages and use a generator to power my pumps and a few lights and although what you are suggesting is tempting I find that a few extension cords leave one nothing to worry about.
I'm even going to put a male and female plug on my electric furnace fan motor so I can run the fan for my attached wood burner.

If you want maximum convenience in an emergency, an approved transfer switch is not that expensive.
 
  #4  
Old 09-07-04, 08:43 PM
Member
Join Date: Aug 2004
Location: NA
Posts: 1,065
No, you cannot backfeed your dryer outlet it is a major code violation. You must be connected through an approved transfer switch that prevents the possiblity of a backfeed to the utility. Your method does not prevent a backfeed possibilty i.e. you must physically turn your main breaker to the sub panel off, if you forget and fire up the generator you will backfeed the utility. A transfer switch does not allow any possibilty of backfeed......Roger

Added thought: many utilities must approve any standby system installed in a single family dwelling. Their websites usually give you the requirements for standby installations. They take this very seriously! As linemen have been killed by backfed utilities from home owner installed generators doing exactly what you suggest...backfeeding a dryer circuit. Dont risk it
 
  #5  
Old 09-07-04, 09:03 PM
Member
Join Date: Jan 2004
Location: Oregon
Posts: 1,219
My turn to jump on the bandwagon

stanstuf, you ask 'is there any major problem?' The answer, is that in the situation that you describe, executed _perfectly_, there is no problem.

But most of the electric code is _not_ designed from the point of view of 'what is the minimum that I can get away with if everything works perfectly', but instead 'what is the minimum that will remain safe given the expected failures of equipment'.

If you were to not open the main breaker, then you could kill a line worker. Not opening a switch is an expected failure of the system that you describe. The _significant_ possibility that someone could forget to open the main breaker is the most significant problem with the scenario that you describe.

Roger mentions that you should install a transfer switch. We it so happens that the cheapest (some might say too cheap) transfer switches available are simply subpanels with back-fed breakers (almost exactly what you describe), with an added feature: a little mechanical interlock that prevents both the main and the back-fed breaker from being on at the same time.

I don't believe that these interlocks are available as a retrofit, but you might be able to get one of these transfer switch panels and use it to replace the subpanel in your garage, giving a safe installation.

-Jon
 
  #6  
Old 09-08-04, 04:28 AM
Speedy Petey's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Nov 2003
Posts: 2,455
"I know its wrong (BACK FEED GENERATOR)"
I love this; I know it's wrong but can I do it anyway.?
If I, or someone else, is not perfectly careful, I can kill someone, is this OK?

No matter what we say some #*@% people will do this crap anyway. All we can do is make it perfectly clear just how dangerous and stupid this is. Then maybe when(if) someone's conscience kicks in they will realize what the real deal is.


Folks will spend hundreds to thousands of dollars on the perfect genset but scoff at another few hundred to hook it up safely. I absolutely don't get this!!!
 
  #7  
Old 09-08-04, 04:51 AM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
One other point that many people forget is that the main breaker only turns off the two hot wires. The neutral remains connected. In a perfect setup this by itself is not a big deal, but an incorrectly wired cord and plug (usually a cord and two plugs) could put 120 volts on the power company neutral.

As has been stated, please do not wire your generator in this manner. If you caused someone to become killed or injured, you would be criminally responsible and would likely go to jail.
 
  #8  
Old 09-08-04, 06:33 AM
stanstuf
Visiting Guest
Posts: n/a
Thumbs up generator back feed

Well your answers were what I was waiting for and I purchased a transfer switch today.
 
  #9  
Old 09-08-04, 08:15 AM
GregH's Avatar
Super Moderator
Join Date: Jan 2001
Location: Manitoba
Posts: 9,930
Upvotes Received: 5
Thumbs up

Your utility workers thank you!
 
  #10  
Old 09-08-04, 10:40 AM
dougm's Avatar
Member
Join Date: Sep 2003
Location: The Colony, Texas
Posts: 917
Along this same topic, something I've been wondering about: What happens in situations where people are generating their own power via solar cells or wind mills... and are allowed to back-feed the utility to run their meters backwards. Is there some type of switch installed in these situations that shuts down the back-feed when there is no power present on the incoming line? These setups will probably rise in popularity again (remember the 70's?) with the rising cost of electricity. Given last month's electric bill, I've been considering a treadmill generator for the kids to ride while they're watching TV

Doug M.
 
  #11  
Old 09-08-04, 03:21 PM
stanstuf
Visiting Guest
Posts: n/a
Wink back feed generator

I purchased a SQUARE D double throw switch model #92351 .This switch will make my complete subfeed panel hot. It will contact the utility line and disconnect the generator in the up position and contact the generator and disconnect the utility line in the down position .I can even switch the neutral cable as the switch is a 3 pole setup.I know I will have to watch the total current draw from the breakers that I turn on .Ithink by doing this setup I will have more choices to power up as my subfeed has 20 breakers .If anyone sees a upcoming problem with this please let me know.
 
  #12  
Old 09-08-04, 07:32 PM
HandyRon's Avatar
Member
Join Date: Dec 2001
Location: New York
Posts: 1,365
Feel free to switch the neutral conductor, then you don't have to remove the neutral to ground bond within the generator (most come bonded by default)
 
  #13  
Old 09-09-04, 04:16 PM
WFO
WFO is offline
Member
Join Date: Feb 2004
Location: usa
Posts: 247
dougm said
"What happens in situations where people are generating their own power via solar cells or wind mills... and are allowed to back-feed the utility to run their meters backwards?"

Anytime you feed into the utility system, you have to be capable of several things. First you have to be syncronized with the system, which means you have to be able to have the correct frequency and voltage in phase with the utility. You have to be able to maintain this frequency (and voltage) as well as have overcurrent protection. You would also have to be capable of disconnecting from the system automatically in an outage to prevent backfeeding and "islanding" (ie-trying to run your entire neighborhood off your 5 kw Briggs and Stratton.) This would include the hardware to connect and disconnect as well as the relaying.

Simply plugging in and running the meter backwards is an advertising fantasy the makers of gen-sets like to promote.
 
  #14  
Old 09-11-04, 04:21 PM
jughead's Avatar
Member
Join Date: Oct 2003
Location: Davenport, Iowa
Posts: 597
I parallel with the utility lines when at work sometime. There's a lot of stuff that has to be done exactly right when you do stuff like that. I'm sure the technology is out there to allow someone to do it at home, but the price would be way more than the average Joe would want to pay to do it correctly. Like the others have said, if it's not done correctly there is a real danger to the utility company line men. Also, if you don't do everything correctly there is a real possability to do significant damage to your own generator.
 
  #15  
Old 09-11-04, 05:28 PM
Member
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
Those people who do generate their own electricity have special equipment that allows them to backfeed to the utility. In most places of the country the utility has to accept (and pay them for) their power.

The equipment used makes sure that the power is properly phased and won't allow the backfeed when the utility side has no power to start with.
 
  #16  
Old 09-12-04, 02:03 PM
Join Date: Jun 2002
Location: Long Island, NY
Posts: 1,531
The utility line voltage is normally "stepped down" before entering the building, by a transformer. The transformer can work in reverse when voltage is sent through it in the opposite direction and "step up" the voltage. This stepped up voltage, back-feeding through the utility lines, may electrocute workers that come into contact with the utility lines
 
  #17  
Old 09-14-04, 06:26 PM
Member
Join Date: Sep 2003
Posts: 344
Not only do your utility workers thank you, but all the customer services reps at the genset maker thank you.
 
  #18  
Old 07-30-08, 05:37 PM
Member
Join Date: Jul 2008
Posts: 1
A little understanding here....

OK, last year I lost $700 in food due to a very unusual six day power outage... so I decided to buy a small generator that would give me just enough juice to keep my fridge running a light or two. I knew (know) very little about electricity and have tried to educate myself for three weeks by reading items such as this and learning the ins and outs of what SHOULD be done. Funny thing is alot of people refuse to even discuss the physics and facts of how electricity / grid-tie / power generation EVEN works. I think this guy's question is quite reasonable. Sure, the potential failure in what he is asking - WHICH CAN LEAD TO SOMEONES DEATH - is human error, forgetting to flip the switch... but very few people are even willing to give you the detail about how electricity really flows and why it shouldnt be done. I even called my own power company to ask them about what I should not do.. I mentioned back feeding - AND THEY WOULDNT even talk to me about it! I want to know (as a person that doesnt know this stuff) what expressly to avoid and WHY.. and they get uppity and angered like you are trying to beat the system... I feel for the person that posted this.. he is getting beat up for a legitimate "please educate me" question. Guess we are all to used to being spoon fed and told what to do.

Originally Posted by Speedy Petey View Post
"I know its wrong (BACK FEED GENERATOR)"
I love this; I know it's wrong but can I do it anyway.?
If I, or someone else, is not perfectly careful, I can kill someone, is this OK?

No matter what we say some #*@% people will do this crap anyway. All we can do is make it perfectly clear just how dangerous and stupid this is. Then maybe when(if) someone's conscience kicks in they will realize what the real deal is.


Folks will spend hundreds to thousands of dollars on the perfect genset but scoff at another few hundred to hook it up safely. I absolutely don't get this!!!
 
  #19  
Old 07-30-08, 07:40 PM
Member
Join Date: Jun 2005
Location: ontario canada
Posts: 381
Originally Posted by jhsandusky View Post
OK, last year I lost $700 in food due to a very unusual six day power outage... so I decided to buy a small generator that would give me just enough juice to keep my fridge running a light or two. I knew (know) very little about electricity and have tried to educate myself for three weeks by reading items such as this and learning the ins and outs of what SHOULD be done. Funny thing is alot of people refuse to even discuss the physics and facts of how electricity / grid-tie / power generation EVEN works. I think this guy's question is quite reasonable. Sure, the potential failure in what he is asking - WHICH CAN LEAD TO SOMEONES DEATH - is human error, forgetting to flip the switch... but very few people are even willing to give you the detail about how electricity really flows and why it shouldnt be done. I even called my own power company to ask them about what I should not do.. I mentioned back feeding - AND THEY WOULDNT even talk to me about it! I want to know (as a person that doesnt know this stuff) what expressly to avoid and WHY.. and they get uppity and angered like you are trying to beat the system... I feel for the person that posted this.. he is getting beat up for a legitimate "please educate me" question. Guess we are all to used to being spoon fed and told what to do.
you state you want to know what to avoid and why.???read the posts before yours they all tell you...what to avoid .....backfeeding your home with your own power...why?...if you forget to throw a switch in your haste to get your freezers running because you are worried about that 700 dollars worth of meat or your wife is screaming she can't watch all my children and you send power back to the utilities lines and kill a lineman whom grabs a wire he "knows" is dead and you kill him ...well then i guess you will be educated beyond your wildest dreams

as far as i can see the original poster has been educated..he said he knew it is wrong and every one agreed with him and educated him on why it was wrong.....he could kill someone, himself, and /or fry his own equipment

i have taken the advise on this same question long before..i have no generator yet (but am saving) but i have installed the transfer switch on my central metering pole and am ready when i can afford it and thanks to much good advice from here and the electricians i work around, when i do have my own and the power goes out, i will feel safe knowing my freezers are running, my sump pump is going, my family is warm and my neighbour down the road who is a linesman is in now way going to be harmed by my producing my own electricity as he works through a stormy night to restore power for everyone else
 
  #20  
Old 07-30-08, 07:49 PM
Member
Join Date: Sep 2000
Location: United States
Posts: 18,497
Suppose a stranger comes to your door. He asks you to explain to him what bad would happen if he poured gasoline all over your house later that night and lit it with a match. Would you take the time to explain it to him, or would you throw him out and call the police? The question you asked your utility was very similar.
 
  #21  
Old 07-30-08, 08:00 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,597
Upvotes Received: 13
Trolls aren't usual in these forums but mods, I think this four year old post has been revived by a troll.
 
  #22  
Old 07-30-08, 08:03 PM
Member
Join Date: Oct 2005
Location: USA
Posts: 1,248
Upvotes Received: 2
anyone read 702.6?

"Temporary connection of a portable generator without transfer equipment shall be permitted where conditions of maintenance and supervision ensure that only qualified persons service the installation and where the normal supply is physically isolated by a lockable disconnect means or by disconnection of the normal supply conductors."

So, who or what "qualifies" a person?
 
  #23  
Old 07-31-08, 12:38 AM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Originally Posted by telecom guy View Post
"Temporary connection of a portable generator without transfer equipment shall be permitted where conditions of maintenance and supervision ensure that only qualified persons service the installation and where the normal supply is physically isolated by a lockable disconnect means or by disconnection of the normal supply conductors."

So, who or what "qualifies" a person?

Telecom guy.,,

This kind of methold is common done in commercal and industrail where they have strict LOTO {LockOut TagOut } procdures and they useally have on site electrician on hand and they can do the producre correct however.,,

The resdentail area that is catch 22 situation and many POCO and Inspectors are very strict on this part and need a transfer switch to isolated the supply from the house and generator so it will not backfeed it at all.

And yes there is a code section related to tempory power useage I think it is in either 701 or 703 one of the two location in the NEC . ( There are few other spot but I have to double check before I can post the extra code #'s)

Merci,Marc
 
  #24  
Old 07-31-08, 04:41 AM
Member
Join Date: Jun 2008
Location: Eastern Georgia
Posts: 486
First: Use a transfer switch!
Second: Do NOT switch the neutral every transfer switch I have installed has a solid neutral connection, the incoming neutral, the one from the genset, and the one going out to the load are all landed on the same bus and not switched. I guess it would not be dangerous to do this, just another place for a bad connection to cause problems for you.
Just my 2 cents.
 
  #25  
Old 07-31-08, 03:30 PM
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
The fridge, freezers, and lamps all plug in to household receptacles. As Greg said nearly 4 years ago in a post above, "a few extension cords leave one nothing to worry about."

It means that nothing is connected to anything that could cause harm to others.

Add "convenience" into the mix and you need a way to (1) power certain circuits, (2) do it automatically or with minimal physical effort, and (3) keep you and your family safe.

(1) A transfer switch is the next best thing to extension cords. It will allow current to pass from either the power grid or the generator (which protects the poco workers). It also allows you to select which circuits are hot in the house. Selecting only critical circuits means saving money on genny and fuel costs.

(2) Home backup systems automatically start the generator and flip the transfer switch when the power goes out. Talkin' thousands of dollars. Or you can save a bunch by connecting & starting the genny and manually flipping the transfer switch.

(3) Any other scheme is potentially unsafe. Plugging a genny into a dryer receptacle with no "either/or" switching could energize the entire house and the grid. At best, you'll blow up an expensive genny. At worst, someone could die.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes