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small invertor gen and subpanel?

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

  1. briansol

    briansol Minister of Fire

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    I've narrowed down choices on a generator to the 2400 inverter generator with the tri carb from these folks:
    http://www.yamaha-propane-natural-gas-generators.com/ef2400is.htm

    it only has 'normal' outlets, not the big heavy duty generator outlet.
    Rated / Maximum AC Current 16.7 / 20 amps @ 120V

    [​IMG]


    I'd like to hook up my pellet stove, fridge, and oil boiler (for hot water mostly), and maybe a few lights/outlets to it, in rotation. maybe a laptop/etc. not looking for full house use--- just enough to manage.

    since all of these are in various parts of the house, running extension cords is just not a good idea. With them costing $50 + each these days anyway, it's probably cheaper for me to just install a subpanel any way with one cord.

    But, the electric box is in the front of my house (I have underground power in my area) and I don't really want to keep the generator in the driveway. I'd like to have it in the backyard, which is fenced in and if its as quiet as they say it is, provided I don't 'show off my light' no one will know I have it on from any distance. But that means running a long wire. Either an outside cord around, or pass wires in the (finished) basement from the outside back wall to the front wall.

    All of the subpanels i'm seeing for generators seem to want the big boy plugs and more amps 30-60.

    Can I do this with a weaker set?

    Or, am I going about using a portable invertor wrong like this.... its meant to power a few items locally, and not use a house connector. I've never used a generator before on my house for any period of time so i'm completely new to this all.

    thoughts?

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  2. Highbeam

    Highbeam Minister of Fire

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    The subpanel setup is a bad idea. That is an inferior and overly expensive way to switch just a few circtuits to generator power. The superior, both cost and function, method is with an interlock kit on your panel. This is also code legal and allows you to power any and all circuits with a genset. The hardest part will be running the new "generator inlet" cicuit from the panel to a convenient place on the outside of your home for a male plug.

    You only need a 240 genset if you want to power 240 devices but with such a small genset you won't be doing that. So you will be making an adapter that plugs into the house side generator inlet which is usually some sort of 30 amp twistlock and then also plugs into the genset of your choice. The adapter will be configured such that your 120 volt power will feed both legs of the panel.

    If, in the future, you acquire a larger genset capable of 240 then it will likely have the proper plug to allw direct connection to the generator inlet.

    Imagine, you'll be able to walk into any room and flip on the light switch.

    The clean power from that yamaha will be very good for your flatscreen TV, laptops, and even pellet stove. Things should run smoothly and quietly with no hum.
    raybonz and daveswoodhauler like this.
  3. velvetfoot

    velvetfoot Minister of Fire

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    That's what I do.
  4. briansol

    briansol Minister of Fire

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    I have no need/use for 240. The dryer and range are the only things I have that are 240 and the hell with laundry in an emergency situation, and I have a nice grill w/ side burners for cooking with propane (which is why I want the tri-carb anyway-- I plan to stock a few grill tanks as fuel storage) :)


    I'm very capable... younger... no medical/etc equipment requirements. I just want a little comforts should we run into Sandy or a Snowpocolypse again. Lost a lot of food both those weeks and cold showers suck!


    So, interlock kit...

    googling....

    yes, That's what i'm after. a plug on the outside of the house to plug the set into, and that plug is on the panel.

    but again, all these kits i'm seeing call for the larger cord.
    [​IMG]

    How does my 'normal' ac outlet plug on this get hook into these things?
  5. velvetfoot

    velvetfoot Minister of Fire

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    You wire up an adaptor. A 120v on one end and a 240v interlock on other end. The plug is wired as generally described above (they can be customer wired). That's how I did it.
  6. begreen

    begreen Mooderator Staff Member

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    It can work. You don't need a giant generator plug wired in. And the Yamaha genny (same as we have) will do the job well. Without seeing the panel and how it is wired, it's hard to advise exactly, you need to assess the suitability for your panel. Contact your electrician to see if you can install an interlock (main breaker lockout), wire up the remote outlet for the genny, install a 20 amp generator breaker at the top of the panel (which can only be engaged when the main breaker lockout is up) and migrate the genny loads to the leg of the panel that the 120v breaker is on.

    Here are a couple examples of the main interlock. They are with 240v breakers, but it can also be done with 120V breakers. This just means that only one side of the panel will be powered.

    lockout1.PNG wpid-main-breaker-interlock.jpg
  7. begreen

    begreen Mooderator Staff Member

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    raybonz likes this.
  8. briansol

    briansol Minister of Fire

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    My house is fairly new construction (1997) so it should be pretty up to date with hook ups. I do have central air in the house and the breaker box is pretty large. There are open slots. (note, I don't plan to run the c/a on gen).

    I followed you until 'leg of the panel that has the 120'.

    are you saying that in general, one side is all 120 and the other 240, and i'll only be able to chose the lessor 'half' based on where the breakers were put?

    And yes, i'm aware of the linemen danger/.backfeeding/etc. I plan to have an electrician do this for me... and i'll need to get a permit to do it as well.
  9. begreen

    begreen Mooderator Staff Member

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    No, the main panel will have two "legs" or bus bars that the breakers alternatively attach to. Each leg carries 120v. A 2 pole breaker bridges both legs to provide 240v..

    I suggest you have an electrician give you a quote. If he is a good guy you may be able to run the remote leg yourself to save a bit of money, but have a pro do the panel work and wire up the new breaker plus generator interlock. An error could be lethal.

    Inside-Main-Breaker-Box-420.jpg
    briansol likes this.
  10. briansol

    briansol Minister of Fire

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    gotchya. thanks!

    any idea on a reasonable estimate for this? 500? 1000?
  11. begreen

    begreen Mooderator Staff Member

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    Not knowing the house or path of the wiring for the remote outlet it would be just a guess. This should take about 3 hrs. so I'd guess less than $500.
  12. briansol

    briansol Minister of Fire

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    Assume easy. The box is at outside-wall level and there's already gromments through the foundation there to the outside.
  13. Highbeam

    Highbeam Minister of Fire

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    BG sent you down one road with moving breakers but there is a better way. You use your 120 volt genset to feed both sides, phases, legs, (whatever you want to call them) of the panel. You do this by combining the two hot leads within your adapter that goes from a twistlok 30 amp to the 120 volt duplex plug on the genset. This makes it so that no 240 volt device will operate which is fine since you don't have a 240 volt genset.

    My home is equipped with an interlock and a generator inlet on the exterior wall. I used a 30 amp inlet circuit since that is standard and will allow for a 7000 watt 240 volt genset should I ever decide I want to use something that big. Sizing that generator inlet circuit to 30 amps and using regular 10 gauge romex is the way to go.

    Feeding a home equipped with an interlock using a 120 volt genny requires some creativity. The creativity is accomplished entirely within the adapter cord between your genset and the generator inlet.
  14. nate379

    nate379 Guest

    If you just feed 120v into the panel wouldn't only one side of the panel be powered? When you feed with 240v you put 120v on each side of the panel.

    I'm not an electrician and I slept on the couch last night so maybe I'm way off on this.

    My gen set is 240v and I use my ~100ft 6 gauge welder's cord to plug it into the welding outlet. I just made an adapter that goes from the end of the welder's cable to plug into the gen set. I just shut the main off and shut off whatever breakers I don't need to have power to. Yes I know most power companies don't like this. Mine doesn't care, they said my setup is just fine. I have it in writing.
    Dave A. likes this.
  15. woodgeek

    woodgeek Minister of Fire

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    I thought the standard was to power both hots tied together by the interlock? That way all 120V circuits are live and all 240V circuits are dead as doornails.

    IIRC, the 240V plug supply has the 120 V single hot from the genny tied to both hots on the 240V outlet. Wouldn't want to plug that into a live 240V outlet....or am I missing something?
  16. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

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    Be interesting to know who put that in writing if MEA is your electricity provider.

    MEA's Tariff, Section 9.09, says:
    Standby generating facilities shall be installed in accordance with the Association's "Service Assembly Guide" and shall include installation of a double-throw switch on the consumer's side of the kilowatt-hour meter, with capacity in either position equal to the total connected electrical load through the switch. All such installations shall be subject to prior approval of the Association in order to ensure the safety of the Association's personnel.
  17. nate379

    nate379 Guest

    Yeah, double throw switch on consumer side of the meter means the panel main One of their engineers came out and approved it. Same deal they had to do for my solar panel install.
  18. Highbeam

    Highbeam Minister of Fire

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    That's how I thought the world worked but then I came up with this....

    I don't think it is standard and you tie the hots together at your adapter, not the interlock. I may not have invented the theory but I was fighting a genset that only regulated the voltage on one leg of its 240 output and then I thought, why not feed both sides of the panel with the same 120? Easy to do, you just combine the normally out of phase hots from the panel and feed them with the single hot from the genset's 120 output. You need to be sure that your one neutral conductor is up to task because it is doing double duty of a normal 240 setup. Not a problem with these small gensets and larger interlock wiring.

    It's the only way to feed all the 120 volt circuits in your panel with a 120 volt genny.
  19. velvetfoot

    velvetfoot Minister of Fire

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    Plus you want to have the flexibility of plugging in a bigger, 240v. generator.
  20. Highbeam

    Highbeam Minister of Fire

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    With the adapter being the device that combines your 120 volt genset to feed both sides of the panel you have a tool. Use it wisely. If you remove that adapter and plug a standard 240 genset into it, you can run everything including 240 volt appliances.
  21. velvetfoot

    velvetfoot Minister of Fire

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    I just wired a 240 volt plug to feed both legs - there was enough room in there.
  22. Dave A.

    Dave A. Minister of Fire

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    Light bulb lights over head. Didn't realize it could be this easy.

    So I've got my 240v dryer 30a close to an outside window, near where I'll keep the generator/ gen set. (Champion 3500/3000 haven't used it yet and was not looking forward to all the extension cords/ plugging and unplugging ref/freezer, small a/c etc.) So if this works I avoid all that and don't need additional equipment installed or an electrician. Have done some wiring in the past, added circuits/ moved them around in the panel, so have some idea what I'm doing.

    Aside from whether it's technically code and all -- just so I know if I do it right it's safe and will work.
    My dryer is on a 60 amp kitchen/laundry sub panel to 100 amp main panel.

    Anything wrong with any of the following:
    1. So I get a 240v dryer cord/plug and wire that to the interlock plug
    edit: correction s/b locking gen plug
    for gen (my gen is only 120 so will wire black on gen to both red and black on dryer cord. This is what I'm most unsure of)

    Power up gen
    2. Turn off main house breaker. (and put tag warning anyone not to turn back on)
    3. Unplug regular dryer plug (30A)
    4. Turn off breakers I don't want power to or might overload gen
    5. Turn off anything I don't want on.
    6. Plug in dryer/gen cord to dryer wall socket and gen

    Power will go from dryer plug into sub panel both legs (actually the only thing 240v right now in the house is the dryer but I realize you can't have 240 by splitting 120 between the two legs) and from there into main panel (both legs). And all the breakers will work normally.

    Edit: am using the wrong term, meant the locking generator plug, not the interlock.
  23. woodgeek

    woodgeek Minister of Fire

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    At the risk of confusing everything further, I thought the interlock panels forced one 240V breaker to be off whenever the main breaker was on (and vice versa). You **can** backfeed a dryer plug with 120 to power your 120V appliances, but if you used an interlock panel (for safety) you couldn't then run your dryer off grid power.
  24. Dave A.

    Dave A. Minister of Fire

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    Will it not operate at all or would it just operate at 120v?

    Another question if anyone knows. Realize that can't use the dryer if I back feed through that outlet, but was just wondering otherwise if only one leg of the 240v for the dryer is hooked up would it run but just at lower output -- take twice as long to dry?
  25. Ashful

    Ashful Minister of Fire

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    Won't run at all. You would have the same potential (i.e. voltage) on both legs of the 240V circuit, so zero voltage between them.

    No, for reason above. Getting 120V to that dryer would mean tying one of the hot legs to ground or common, something you don't want to mess with.

    What Highbeam has proposed, with regard to running both legs of your panel off the same 120V potential, is an interesting idea. The required neutral would have to handle the combined load, whereas the neutral in a 240V circuit only handles the small difference in load between the two hot legs. In any case, some newer dryers do have a 4-wire hookup, 2 hots + neutral + ground. More common is the 3-wire hookup, meaning there's more often no opportunity to back-feed your panel at 120V from a dryer plug.

    That said, the dryer plug technique is used by many for a 240V back feed, safe or not. The trouble with this setup is more with regard to making a mistake and throwing the wrong breakers in the wrong order, or having someone get at the panel when you're not around, than anything else.

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