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small invertor gen and subpanel?

Post in 'DIY and General non-hearth advice' started by briansol, May 17, 2013.

  1. Joful

    Joful Minister of Fire

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    Nice. Having always lived in big old houses that have seen many additions, I've always wished I had a breaker panel that neat.

    My current main panel has three sub-feeds in it. Two of those three sub-panels have additional sub-feeds to other panels down the line. You get the idea...

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  2. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Every time I think about getting fancy I read these generator threads and just go back to being happy with the four 12/3 extension cords run from the genny shed.
    jharkin, woodgeek and Joful like this.
  3. briansol

    briansol Minister of Fire

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    I hear that. I'm thinking about going this route as well at least at first. Those cords are about $50 a pop these days, So i was thinking for $200 and maybe a little more, could I do it the RIGHT way? And not have to trip over cords, or fish them through cracked windows, etc etc...
  4. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    I think about a neighbor a few lots from mine. After a week long outage in 2009 he had popped $21,000 for a whole house autostart rig complete with 500 gallon propane tank. Since then he has lost power for three hours, one time.
  5. briansol

    briansol Minister of Fire

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    ouch. yeah, i looked at getting a whole house set up. Cheap ones were 8 grand for the unit alone. I see some others are 3500/4000 bucks but those are diy from northen tool/etc and i'm not really up for that. $1500 is about the most i want to spend. That's about what i'll have total in meat at any one time in the house anyway. Above that, it's cheaper to just throw the meat out. lol
  6. Joful

    Joful Minister of Fire

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    $7000 per hour. Wonder what his kWh rate works out to? Hard to criticize the guy though. He'd have looked like a genius if you guys had the week-long Sandy outages most of my neighbors suffered.
  7. begreen

    begreen Mooderator Staff Member

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    BS. When there is a power outage it usually is because a line is down. If that line is down and there are just a few houses between you and the break, a very lethal shock can happen if the linesman thinks the line is dead. Even if not lethal, if he falls from the bucket he is not likely to do well.

    http://www.powerlineman.com/lforum/showthread.php?711-Storm-Death
  8. begreen

    begreen Mooderator Staff Member

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    Backfeeding through a dryer or welding outlet with no neutral is a bad idea, don't do it. Also, backfeeding both buses in the panel could have bad consequences if you have a modern stove or dryer with digital readout, heat pump or heatpump hot water heater, etc. installed and you fail to turn off all 240v breakers first. Repairing fried electronics in some of these appliances can get very pricey. Turn off the main breaker, then turn off all 240v breakers. And if you have a grid-tied solar array, disconnect that too. Play it very safe here folks. If you don't know exactly what you are doing, stick to extension cords or pay an electrician to wire up things correctly. Often the power goes out after dark. When setting up to run from the generator, you don't want to be fumbling, soaking wet in the dark during a big storm. Do some practice runs on a nice dry sunny day to be sure you have the drill down right and tape a preflight check list on the inside of the main panel door to be sure you don't forget anything.
    woodgeek, jharkin and Redbarn like this.
  9. FanMan

    FanMan Feeling the Heat

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    At my cabin (where my electric needs are minimal, just lights, ceiling fan, and stereo) I backfeed the house with a 120V suicide cord from a 650W Honda portable generator into an outdoor 120V socket, and a jumper cable with spring clips to bridge the legs at the main disconnect. Bad, unsafe, whatever, but it works and it's only my wife and I. Our power there has been out since Sandy and we're expecting another month before it's restored.

    At home, I recently replaced my electric dryer with a gas dryer, freeing up the 240V line which I moved to the outside of the house... that will be the generator input, gotta buy a bigger generator before the next hurricane (had week long power outages for both Irene and Sandy).
  10. jharkin

    jharkin Minister of Fire

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    This thread just confirms my plan to steadily eliminate all the 240V loads in my house. The dryer is the only one left and that I can live without in a power failure. I would love to chuck the noisy 3K job for a smaller inverter set.
  11. jharkin

    jharkin Minister of Fire

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    Genius? For that money he could have put his family up in the Ritz all week and still had a lot of cash left over...;)
  12. jharkin

    jharkin Minister of Fire

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    Ha ha sounds familiar. We got rid of all the subs and fuse boxes and managed to consolidate it in one panel with a new main drop off the street.. Yet it still looks like a mess. Lots of splices inside the panel extending old BX runs that were not long enough to reach the breakers etc.

    It is theraputic ripping out old unused lines though inst it? Especially fun when I find live ones hanging cut off in the crawlspace just waiting to torch the place...



    One other point... The 1996 NEC revision introduced the requirement for 4 wire outlets for Dryers and ranges. So you will see a 4 prong outlet in any house built more recently than that. You also are supposed to update to a 4 wire if you "move or substantially modify" an older outlet.

    Even when it was legal, a 3 wire 240/120 outlet was supposed to be wired with SE type cable that has the heavy braided ground and was capable of carrying the neutral load.
  13. Highbeam

    Highbeam Minister of Fire

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    Between my new panel and the ceiling, I installed a large gutter box (metal box) and in this box I spliced on extensions to each circuit so that the wires could make it to their new breaker locations. Whole lotta wire nuts in that box.

    If you discontinue a circuit and pull the wire from the panel, must you remove it from the structure or do you leave it dead in the walls and attic?
  14. Joful

    Joful Minister of Fire

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    Judging by the amount of old knob and tube stuff I find decomissioned in old houses, I'd say most just leave it. I always try to remove when I can, but would not destroy a wall to do so. I have not seen code specifying one way vs. the other.
  15. nate379

    nate379 Guest

    Lineman are trained to treat all lines as live, even if they aren't. They have fall harness on when in the bucket truck.
    A few of my friends are linesman so this is coming right from the source... one is sitting on my couch stealing my beers right now actually.

    A 4-5Kw gen set would have trouble powering more than 1-2 houses unless they hardly had anything on.

  16. nate379

    nate379 Guest

    It's not any different than adding in one of those plugs to backfeed into. Just about every dryer made in the last 10 years uses a 4 wire plug. A welder is normally two hots and a ground but the ground can be run as neutral, the welder doesn't care and it's still prefectly safe. Ground and neutral are bonded in many panels anyhow.

  17. Highbeam

    Highbeam Minister of Fire

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    That's too much. Both items are illegal and unsafe. Maybe I am misunderstanding you?

    The ground in a welder circuit (any big three wire romex) is undersized. It is undersized since the only function is to pop the breaker. Not designed to be a current carrying conductor so trying to make it work as a neutral could burn it up and cause a fire.

    The ground and neutral are only bonded at the main panel. One place only.
  18. Seasoned Oak

    Seasoned Oak Minister of Fire

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    Thats was the second of 2 reasons i got a wood stove in the first place. I could either pay out big bucks for equipment i may or may not ever use(BIg generator) of pay out smaller bucks for something that 1. Would pay for itself. 2.I would use often. And 3 would work and provide heat and cooking ability even if the power went out for a month or more. It was as they say a no brainer.
    briansol likes this.
  19. nate379

    nate379 Guest

    All depends on the wiring I suppose. My welder circuits are 50 amp and use 6 gauge wires. My generator has a max output of 16 amps at 240v. It's plenty big enough wire... by several sizes.

    Yes ground and neutral at the main, that is why I said "many panels" and not all or most.

  20. Dave A.

    Dave A. Minister of Fire

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    From what I'm reading just using extension cords from the gen to your appliances and devices is not so uncomplicated as it seems. First you need to know if the gen has a floating neutral or a bonded neutral. And then you need to sink a ground rod at the gen, hook up ground and possibly bond the neutral and ground at the gen with a dummy plug.
  21. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Joful likes this.
  22. velvetfoot

    velvetfoot Minister of Fire

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    And if a portable generator was connected to house wiring using a power inlet with interlock at the panel, the ground and neutral should not be connected at the generator, only back at the panel? As in, only one place where neutral and ground are bonded?
  23. Highbeam

    Highbeam Minister of Fire

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    There is great mystery and inconsistency with the whole "floating" neutral thing with generators. After much head scratching, it becomes evident that all you do is plug the genny in to the house's inlet plug which has all 4 wires and in no case is the portable genset grounded to rods at the genset. This is one of those internet situations where you can do a search and find no consensus. It might drive you crazy trying.
    Joful likes this.
  24. jharkin

    jharkin Minister of Fire

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    What I read in more than one place is:

    For connection to the house via an interlock or transfer switch where the generator is wired through a 4 wire connection
    • Do not bond the ground and neutral at the generator
    • Do not use a ground rod at the generator
    The theory is that if the ground is bonded at the genny you now have neutral and ground bonded in two places (gen and main breaker box) and its possible for neutral current to flow to the generator over the ground wire. The generator grounds to the house ground rod via the 4 wire cable.​

    For use with extension cords
    • Bond ground and neutral at generator
    • use a ground rod at generator
    My genny had a bonded ground. I rigged it so I can connect/disconnect it as needed and have a piece of welding rod with a thick cable wired to the ground lug that I can use as a simple ground stake when using it as a portable.
    woodgeek and Highbeam like this.
  25. jharkin

    jharkin Minister of Fire

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    Same Ias I have seen. Professional electricians never seem to take the time to rip out old stuff, they just disconnect and run new in parallel. That's if you lucky and they dont do something scary like tie romex into an old KT or other ungrounded stuff. In my house we had remnants of KT, early ungrounded fabric covered NM, armored BX and many different variations of romex, all mixed up.

    (Off topic, but knob and tube is actually quite safe to use if its in good repair, not covered up with insulation and not overloaded or used with anything that needs a ground. But that's almost never the case and insurance companies are afraid of it so we tend to just rip it out as a matter of course)

    In my house .... Everything thats dead that I can get to, I rip out. All the old stuff other than the armored BX that tests with a decent ground I replace with NM-B. Since I have a small cape most of the wiring is exposed in the basement or up in the attic crawlspace. Only whats in the walls of the few unrenovated rooms is left.

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