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A QUESTION for home electrical wiring experts

Discussion in 'Work Safe' started by nitesite, Oct 5, 2021.

  1. nitesite

    nitesite Average Guy Moderator "Philanthropist"

    Messages:
    6,135
    Lets just say hypothetically that someone has a small gasoline inverter generator, and a long 12-ga extension cord that has been converted to have male NEMA 5-15 ends on both sides.

    If someone were to plug that cord into a room wall receptacle, say maybe a bedroom or living room or kitchen... and then into the generator, and start it up....

    ... does that energize just the room and whatever else is on that individual circuit breaker?

    Or would it feed the whole 120V side of the circuit breaker box?

    Of course, this is entirely hypothetical and all safety precautions like cutting all main breakers that lead outside, have been done.
  2. Ernst

    Ernst .30-06 Supporter "Philanthropist"

    Messages:
    1,075
    First, and most importantly you must disconnect the service disconnect in your main circuit breaker box so you don't feedback any generator power to the power grid.

    There are two possible scenarios

    If you turn off the circuit breaker which provides power to your selected outlet then only the plugs / lights on that circuit will be powered.

    If you do nothing, other than disconnect the service disconnect, power will be distributed to all 120 circuits on the side of the breaker box where the circuit breaker is located. No other circuits will be powered.

    Here's the consideration. Your 12 GA wire will only power a specific amperage load before it overheats and or pops the breaker on the generator. Be careful.

    If your generator has a 220 outlet I've seen folks induce power through a welder or dryer circuit. This would typically power every circuit in the house.

    The safer way is to run a heavy extension cord(s) from the generator to power your refrigerator and other important items.

    Just be careful.

    Regards
    Woods Wanderer and nitesite like this.
  3. nitesite

    nitesite Average Guy Moderator "Philanthropist"

    Messages:
    6,135
    One of my sons was talking about getting a small inverter gen for storm power outages, because he and his wife and kids couldn't stand being without wi-fi.

    So he asked me about the cord idea and would it just power the room.

    I told him that I had no idea.

    I ain't no electrician!!!!
  4. Ernst

    Ernst .30-06 Supporter "Philanthropist"

    Messages:
    1,075
    Better and safer to run extension cords and just plug in items you want to power.

    Back flowing electricity to circuits possible but dangerous if you don't know what your doing.

    Regards
    nitesite likes this.
  5. John A.

    John A. Unconstitutional laws are not laws. Staff Member Administrator Global Moderator

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    15,983

    Here's a few things. Many breaker boxes don't typically use a "row" anymore. They're more commonly a zig zag pattern inside the breaker box most of the time, but if it's an older box, it may be just the row. If it's newer, it's very likely to be zig zag.

    What you're referring to is often called a suicide cord. It will feed back to everything that is on that circuit and also power whatever is attached in the breaker box (the row or zig zag that was mentioned earlier), so you need to be mindful of what all you are trying to power. It' doesn't take long for a 16ga extension cord to get too hot and melt/burn if too much stuff is on it.

    I used 12ga romex to go from the generator to the small panel. And as I mentioned, I don't have a lot of stuff on the generator either. Certainly no 220v stuff like oven and furnace and dryer and stuff.

    I wired my box a little differently when we did a major remodel a few years ago. My house is old and has a 100A service breaker box. Yeah, I know it should probably be twice as big, but it's worked for the last 70 years so I'm not mucking with it.

    With that said, when we added the addition onto the house, I got a small 8 breaker panel and moved everything that I wanted to run off the generator, so I can knock the 50A double pole breaker that would normally feed over into the small box. This prevents the power from feeding back into the 100A main. And back through your transformer and back out onto the line. But I do also knock my main breaker as well as a failsafe.

    The major things that I moved over to the small panel were all the interior lights, the fridge and deep freezer, a couple of outlets in the kitchen and living room wall (those few outlets are on the same circuit because they're in the same load bearing wall). My generator is small (1500w) but it will keep up with the fridge and deep freezer and a few lights and a tv/dvd player for the grandkids if they want to watch a movie or play their game or something.

    Now, with all of that said I want to bring this to their attention. Where your wifi router is concerned, unless the company that is providing internet has battery backup power supplies in the system to get the internet to you, it's either going to be out, or will very likely be out as soon as the battery backups are drained when the power is out for a prolonged period because throughout the catv and phone system, they have to power it so the amplifiers and other things work and when it's out, so is their service, so unless it's powered from somewhere else from where your home is getting its' electricity, the internet is going to probably be out anyway with or without a generator. I just wanted to throw that out there. You'd need to ask your internet provider that question. Most any service tech can answer that in a few minutes if they're familiar with the system where you live.

    It is generally safer to run an extension cord from the generator to one of those multiple outlet surge protector things when you can. But it is more convenient if you can just power a few breakers in a box, as Ernst mentioned, IF it's not overloaded and it's done right.
    nitesite likes this.
  6. nitesite

    nitesite Average Guy Moderator "Philanthropist"

    Messages:
    6,135
    Now that you mention it, I remember when I was a cop stopping to talk to a cable TV crew who was working on something. I asked, "WTH are those green lights on those grey metal boxes all about?"

    And they said that the green light meant that the internal battery was up and ready to push the signal along. No green light, no battery back-up.
    John A. likes this.
  7. John A.

    John A. Unconstitutional laws are not laws. Staff Member Administrator Global Moderator

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    15,983
    There are many companies who do not have battery backups on their power supplies at all.

    No power, no cable and no internet.

    Though, these days, is becoming more rare not to have them, but there are still a lot out there that don't.
    nitesite likes this.
  8. Bobster

    Bobster .30-06 Supporter

    Messages:
    2,614
    To answer your question in two parts: NO, there should NEVER be any kind of double-male plug cord created for ANY reason--it is a recipe for disaster, fire and/or electrocution. But hillbillies are going to hillbilly ;) so YES, what the cord will do is to "backfeed" 120v all the way to the electrical panel, then feed all of the other circuits on that leg. There will be another 120v leg in the box coming from the pole for a total of two "lines" in totaling 240v and a neutral (white). This is assuming you/he don't have 3-phase which is rare in residential settings and is more commercial as are higher voltages such as 480v. So essentially the cord will power "half" the circuits in the house--whatever is connected to that "side" of the panel. GFCI outlets and breakers will probably not work. You could isolate the circuit by turning off all the other breakers on that leg.

    As John mentioned, the breakers may "zig-zag" in the box--easiest way to find out is to pull the panel cover and have a look. This pic is of a sub-panel at my shop--I needed to get another breaker so I took a pic with my phone and went to the home store. I've turned the pic so it more looks like what you might have at home with breakers up and down. I did not wire this nor did I direct short something at one time (the scorch) :eek: . You can see the black wires going out the top to another sub-panel (and also thicker coming in). One wire going to one leg is just black (line), the one going to the other leg has red tape on it (another line), one has white tape on it (neutral) and one has green tape on it (ground).

    The other pic was something I found on the interwebs and was in my archives... PS: what I call a "leg" is also called a bus or buss bar.

    subpanel90.jpg


    home_electrical_breaker_panel.gif
    Last edited: Oct 6, 2021
    nitesite likes this.
  9. MikeD

    MikeD I'm Your Huckleberry Staff Member Global Moderator "Philanthropist"

    Messages:
    12,443
    I admit to doing this at my cabin but...I only have generater power and I needed a quick way to swap out generaters if my primary failed (which was quite frequently at that time) Also I used a twist lock so it cannot easily fall out or be pulled out.

    That said, I do not recommend it and it retrospect should have wired a male plug to the receiving end. At the time I worked with the materials I had.

    At home most of my friends backfeed through a dryer or AC recepticle.

    One friend wired a sep. curcuit that is only connected to the generator. If the power goes out he just plugs his fridge/freezers/sump into that circuit and plugs it into his generater. That is a much safer way to do it as there is no possability of interation with other electrical. But it does take more effort to set up and is not as adaptable if you move stuff around
    nitesite likes this.
  10. Bobster

    Bobster .30-06 Supporter

    Messages:
    2,614
    In the event of power outage and lines down (ie: hurricane/tornado), the power company MIGHT bypass a "hot" circuit energized by a generator. Usually they are polite and will knock on your door and tell you to turn the damn thing off! ;) Don't forget to turn the main breaker off to eliminate the possibility of backfeeding to the power line! :eek:
    John A. and nitesite like this.
  11. John A.

    John A. Unconstitutional laws are not laws. Staff Member Administrator Global Moderator

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    Yeah, anytime you use a generator or invertor at your house, knock the main first. If it back feeds through your transformer to the main power line, that 120v AC could be bumped up into the 440v territory or more and kill some unsuspecting lineman somewhere down the road.

    You knock the main before you even pull the rope or turn the ignition and start the generator. ALWAYS> !!!!!

    That's like making sure a gun is unloaded before you clean it. ALWAYS>!!!!

    numba won wool.

    [​IMG]
    nitesite likes this.

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