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Old 07-18-2016, 10:50 PM
Vicsage Vicsage is offline
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Question for electricians

Lets say my city has a blackout. I have a portable generator. I make an extension cord that has a male fitting on each end. I go to the fuse box and turn off the circuit cutting the power to one of the rooms in the house (I know it has no power due to the blackout). The room has 5 outlets. I take the extension cord, plug one end into the generator and the other end into one of the 5 outlets. My questions are, will this supply power to the other 4 outlets? Will the rest of the house still be powerless? Will the power go out to whoever may be working on the powerlines? Will I burn my house down?
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  #2  
Old 07-18-2016, 10:59 PM
beowulff beowulff is offline
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Too many unknowns.
Rooms are not necessarily organized by breaker, and outlets in a single room may be powered by different breakers.

In theory, if everything is working as it should, your idea will work correctly, and you will be able to power just the one room. But, it's against code, and dangerous to linemen, so you shouldn't do it.
  #3  
Old 07-18-2016, 11:17 PM
friedo friedo is offline
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The correct way to do this is with a NEC-compliant transfer switch and an inlet receptacle. The transfer switch ensures that your house is completely disconnected from the grid so you don't electrocute any lineman, and the inlet receptacle is where you plug your generator into. You can set this up to power your whole house or just certain circuits, depending on how big a generator you get.

It is never acceptable to make or use an extension cord with two male ends. Do not do this under any circumstances.
  #4  
Old 07-18-2016, 11:20 PM
Silophant Silophant is online now
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Right. If you flip a breaker, it will cut the connection between that circuit and the rest of the house/grid. If you then plug your suicide cord into one of the outlets on that circuit, all of the other outlets on that circuit will be live. Note that "all of the other outlets" could be no other outlets at all, all the outlets in one room, half the outlets in one room and half the outlets in another, or really any combination of outlets in your home. Any outlets not on the circuit will remain dead.

However, if you mess up and plug into an outlet on a circuit besides the one you opened, every outlet on that circuit and every other circuit (except the one you opened) will become live, and your generator will backfeed through your transformer, energizing the distribution lines and endangering linemen who are expecting everything downstream of the substation breaker to be deenergized. This will also overload your generator, since it'll be attempting to power your whole neighborhood.

Additionally, unless you're in the UK, your outlet doesn't have a circuit breaker or fuse on it (since power's only supposed to be flowing one direction - through the breaker in the breaker box), and you could very easily overload your wiring and start an electrical fire in the wall.

Sicide cords (male on both ends) are called that for a reason. If you wish to have a generator powering your wall outlets during a blackout, have a licensed electrician hook up a transfer switch that will switch the main feed from your service to the generator, both preventing backfeeding to the grid and allowing all your circuit breakers to do their jobs. If you want just specific circuits powered during an outage, rather than buying a generator big enough for your whole house, that's doable too.
  #5  
Old 07-18-2016, 11:38 PM
engineer_comp_geek engineer_comp_geek is offline
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Homes in the U.S. are generally fed from a split phase (aka center tapped) transformer. You have two "hot" lines and a neutral coming into the house. From either line to neutral is 120 volts, and from line to line is 240 volts. From the breaker box, the 120 volt circuits are generally split between the two lines, and the 240 volt circuits use both lines. Breaker boxes vary, but most alternate lines as you go down the row of breakers, line 1, 2, 1, 2, 1, 2, etc. A 240 volt breaker just takes up two slots so it gets both line 1 and line 2.

From the breaker box, the lines run all over the house. In some houses, the wiring kinda makes sense. In others, I sometimes wonder if the electrician that wired the house was drunk at the time.

There are some homes that will have all of the outlets in a room on the same breaker. There's no guarantee of that, though. In my house, the outlets along the outer walls are on one breaker, and the outlets on the inner walls are on a different breaker. It mostly comes down to where it was most convenient for them to run the wires when the house was built.

The proper way to hook up a generator is with a transfer switch, as was already mentioned. Generators that can power an entire house are a bit pricey, so most folks don't have one that can come anywhere close to that. It's fairly common to have two panels. The main electrical feed comes into the first panel, and then that goes to a transfer switch to the second panel, and then all of the loads that the generator can power are attached to the second panel. In normal operation, the second panel feeds from the first panel. When the power goes out, you can switch the second panel over to the generator, which also safely disconnects it from the main panel. Now the generator powers everything on the second panel, and everything on the first panel just has to go without power until the power is restored.

Even a second panel can be a bit costly for many folks. If all you have is a cheapie generator and can't afford a second panel, get yourself some extension cords and power strips if necessary and use those when you run the generator. That way there's no chance of you backfeeding into the house circuits and creating a potential hazard.

Quote:
Originally Posted by friedo View Post
It is never acceptable to make or use an extension cord with two male ends. Do not do this under any circumstances.
That's worth repeating.
  #6  
Old 07-18-2016, 11:42 PM
aceplace57 aceplace57 is offline
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Here's what I did before getting my whole house generator.

I ran standard romex under my house. Putting one plug in my bedroom, 1 living room, and 2 in my kitchen (one for the fridge and one for the hotplate). that's all my 2000W portable Honda gen could handle.

the plugs weren't in the wall. I just drilled through the floor, ran the wire and put it in a standard outlet box. It could be removed in less than an hour. Base molding would cover the holes.

at the end of the Romex wire the last receptacle into a box and have it close to where the generator will operate. Make a cord with double 3 prong plugs. This is safe! Because this circuit does not run into the panel. It's hooked into NOTHING. Plug it into the gen circuit receptacle and the receptacle on your generator. DO NOT FUCK UP and plug it into the generator first! That would be very dumb and lethal.

This beats the hell out of running extension cords all over the house. It's safer too. No tripping hazard. No hazard of the dog chewing the cords. It worked great. i had lamps in three rooms of the house. My fridge ran. I had a outlet to plug in the coffee pot or hot plate. Not bad for a small 2000W generator circuit.

Afterward unplug it from the generator. The circuit is now inactive and ready to use when needed. Sure beats spending thirty minutes coiling up 6 extension cords and storing in a closet.

Last edited by aceplace57; 07-18-2016 at 11:46 PM.
  #7  
Old 07-18-2016, 11:54 PM
aceplace57 aceplace57 is offline
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Be extra, extra, extra safe. You should plug in the generator circuit before starting the generator. That way there is no power. Even if you do something stupid like plugging it into the generator first.

that's how I always did it. Power Failure. Say a few curse words. Drag generator out of closet. Add gas. Plug into my special circuit. Start generator.

Power returns. Stop the generator. Unplug the circuit. Let it cool down. Put generator back in closet.

you're never exposing yourself to voltage.

btw, I used standard quarter round base molding to cover the holes in the floor after getting my whole house generator. Noone will ever know what I did.

Last edited by aceplace57; 07-18-2016 at 11:58 PM.
  #8  
Old 07-19-2016, 12:17 AM
friedo friedo is offline
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Quote:
Originally Posted by aceplace57 View Post
btw, I used standard quarter round base molding to cover the holes in the floor after getting my whole house generator. Noone will ever know what I did.
Good for you. And if you had spent an equal amount of time actually doing it correctly in the first place, there would be no holes in your floor to cover up.
  #9  
Old 07-19-2016, 12:24 AM
aceplace57 aceplace57 is offline
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<shrug> the circuit I ran was standard wiring and could have been run into the panel. Using 12 gauge grounded Romex running into electrical boxes with receptacles. That's a lot better than the 16 or 18 gauge extension cords typically used all over the house during a power failure. I used extension cords for a couple years and despised them. They a are a big tripping hazard.

all I did unusual was not wiring the circuit into the panel. That eliminates any danger of back feed. It's a isolated circuit that's only connected to the generator.

Last edited by aceplace57; 07-19-2016 at 12:26 AM.
  #10  
Old 07-19-2016, 01:38 AM
aceplace57 aceplace57 is offline
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A transfer switch is a better option if you can afford the installation. You'd want a bigger generator too.

I don't recall them in the hardware stores 25 years ago. Electricians could buy them from their electrical suppliers. HD sells them today. But wiring one up is beyond my skill set.

We were just trying to get away from using kerosene lamps and candles during outages. They caused so many fires.
  #11  
Old 07-19-2016, 04:37 AM
bob++ bob++ is offline
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American wiring is weird, with all those breakers connected to random outlets. If I lived there I would want to know which breaker controlled each outlet in the house - maybe an hour's work with a test lamp and someone at the breaker board.

My UK house has three power circuits (and they are circuits since they make a complete ring). One for downstairs powder and one for upstairs; both rated at 16 amps, and one 30 amp line to a box in the kitchen to power my oven. They are all clearly labelled by the installer. 5 amp light circuits are similar, with one for downstairs, one for upstairs and one for garage and external.

Once every year or so, I press the red button that trips all the breakers, just to be sure they still work.
  #12  
Old 07-19-2016, 05:22 AM
FinsToTheLeft FinsToTheLeft is offline
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Quote:
Originally Posted by aceplace57 View Post
<shrug> the circuit I ran was standard wiring and could have been run into the panel. Using 12 gauge grounded Romex running into electrical boxes with receptacles. That's a lot better than the 16 or 18 gauge extension cords typically used all over the house during a power failure. I used extension cords for a couple years and despised them. They a are a big tripping hazard.

all I did unusual was not wiring the circuit into the panel. That eliminates any danger of back feed. It's a isolated circuit that's only connected to the generator.
There is nothing wrong with a completely separate generator circuit. The part that is wrong and dangerous was the suicide cord. If you had just used one of these and a regular extension cord it would have been 100% safe. Under $20 to prevent someone from getting killed seems like cheap insurance to me.
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Old 07-19-2016, 05:55 AM
Crafter_Man Crafter_Man is offline
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Last year I made a "suicide cable" for plugging our Honda gas generator into our home.

It is definitely not to code and I do not recommend anyone else doing it. I am relating this for reference only...

I first installed a 240V/40A receptacle in the basement near an outside door. I then made a 20' cable that plugs between the generator and the receptacle. This cable has a male plug on each end.

When the power goes out, I simply turn off the main breaker in the panel, connect the 20' cable between the generator and the 40 A receptacle, and then close the circuit breaker going to the receptacle.

It works great.

I addition, I built a box that monitors the current and voltage of each 120 V leg of the generator. It also monitors the voltage coming into the house (before the main breaker), and a buzzer will sound to let us know when the power is once again available.
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Old 07-19-2016, 07:04 AM
aceplace57 aceplace57 is offline
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Quote:
Originally Posted by FinsToTheLeft View Post
There is nothing wrong with a completely separate generator circuit. The part that is wrong and dangerous was the suicide cord. If you had just used one of these and a regular extension cord it would have been 100% safe. Under $20 to prevent someone from getting killed seems like cheap insurance to me.
That's a great idea. I'd never seen a male receptacle before. I definitely would have used it in a electrical box to more safely connect my generator.

Hopefully others reading this thread will know what to do from now on.
Quote:
Originally Posted by bob++ View Post
American wiring is weird, with all those breakers connected to random outlets. If I lived there I would want to know which breaker controlled each outlet in the house - maybe an hour's work with a test lamp and someone at the breaker board.

My UK house has three power circuits (and they are circuits since they make a complete ring). One for downstairs powder and one for upstairs; both rated at 16 amps, and one 30 amp line to a box in the kitchen to power my oven. They are all clearly labelled by the installer. 5 amp light circuits are similar, with one for downstairs, one for upstairs and one for garage and external.

Once every year or so, I press the red button that trips all the breakers, just to be sure they still work.
  #15  
Old 07-19-2016, 11:18 AM
Me_Billy Me_Billy is offline
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1. Electricity works backwards! In theory you could send electricity out onto the electric wires on pole outside, it could then travel backwards through the transformer and create high voltage going to the lines on the top of the pole... Then an electrical worker or someone touching a downed power line could be electrocuted - YOU would be at fault!

2. Don't do it!

3. Have a proper transfer switch installed for your specific type of generator. There are details as to if the generator has a GFCI or not and if you would need a "neutral switching transfer switch" or not. Terms like "separately derived system" and "non-separately derived system" are used. Get all the proper installation instructions from the MANUFACTURER of your specific generator for your specific model.

4. Everything has electronic controls these days. Furnaces, A/C, refrigerators, microwaves, TV's, computers, etc. Old style generators create "dirty" electricity. Get an "electronics friendly" generator and your electronic gizmos will be happy!
  #16  
Old 07-19-2016, 11:42 AM
friedo friedo is offline
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Quote:
Originally Posted by aceplace57 View Post
That's a great idea. I'd never seen a male receptacle before. I definitely would have used it in a electrical box to more safely connect my generator.
If only someone had mentioned in an early post in this thread.

Quote:
Hopefully others reading this thread will know what to do from now on.
Indeed.
  #17  
Old 07-19-2016, 02:12 PM
mixdenny mixdenny is online now
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Quote:
Originally Posted by bob++ View Post
American wiring is weird, with all those breakers connected to random outlets. If I lived there I would want to know which breaker controlled each outlet in the house

You're right, and that is the way that most newer homes are wired. In my house a card lists every circuit in the main panel and shows exactly what it is connected to. But there are lots of older homes where knob and tube wiring was originally used and updated God knows how. Plus old fuse panels with 6 circuits have been replaced and added on to. It is just safer to not make assumptions.

In the areas I have wired, like the garage, I follow the practice we used at work, and every outlet is also marked as to what breaker feeds it. This is in addition to the table in the main panel.

Dennis
  #18  
Old 07-19-2016, 03:40 PM
Gorsnak Gorsnak is online now
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Quote:
Originally Posted by Crafter_Man View Post
Last year I made a "suicide cable" for plugging our Honda gas generator into our home.

It is definitely not to code and I do not recommend anyone else doing it. I am relating this for reference only...
No matter how safe you think you are being, the whole point of electrical safety code is to prevent dangerous situations from arising if people screw up, forget things, or have an accident. Because we all screw up, forget things, and have accidents. You system may "work great" but it truly is an accident waiting to happen. Transfer switches just aren't that expensive. Don't make other people's lives depend on your attentiveness.
  #19  
Old 07-19-2016, 03:59 PM
Snnipe 70E Snnipe 70E is offline
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f you don't kill someone it may work.
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