1. Welcome Hearth.com Guests and Visitors - Please enjoy our forums!
    Hearth.com GOLD Sponsors who help bring the site content to you:
    Hearthstone Soapstone and Cast-Iron stoves( Wood, Gas or Pellet Stoves and Inserts)
    Caluwe - Passion for Fire and Water ( Pellet and Wood Hydronic and Space Heating)

generator suggestions? Have a well and electric hot water heater

Post in 'DIY and General non-hearth advice' started by DianeB, Oct 27, 2012.

  1. DianeB

    DianeB Feeling the Heat

    Joined:
    Apr 26, 2012
    Messages:
    397
    Loc:
    Foot Hills of the Berkshires
    What size generator would I need to operate both or would I operate only one at a time. Also would like to keep Fridge running. Don't "need" the TV in an outage, but a few lights would be great and enough juice to operate radio.

    Helpful Sponsor Ads!





  2. seige101

    seige101 Minister of Fire

    Joined:
    Mar 25, 2008
    Messages:
    530
    Loc:
    Palmer, MA
    Running an electric water heater off a generator is impractical. You would need a 10,000 watt generator to run your well pump and hot water heater at the same time. Then 80% of the time you would have that large generator running drinking gas like crazy when it has barely any load on it. Depending on how much power you well pump draws and especially at startup you could get away with as small as a 5500 watt continuous. You will be able to keep the majority of the house running and off less fuel to boot. Remember last year a lot of gas station didn't have power so it was important to conserve fuel so you didn't have to wait in a several hour line daily to get gas.

    I did have a friend who wanted to be able to run the entire house (electric hot water, well pump and central air) he bought a 12,000 watt pto driven generator for his tractor. He went with the PTO generator because he usually has 150-250 gallons of diesel on hand. However he is going through approx 25 gallons of fuel running all day or 15 shutting it down so often.
  3. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,026
    Loc:
    The island of Rhum Boogie
    Your well pump is going to require 230v, so think of that for starters. Around 5000 watts is a typical size for running a well pump. If you want to nail it down you're going to have to do the math and add up everything you think you're likely to need. Important thing to remember is starting watts is different than running watts. As an example my old generator was 4000w, but had a surge up to 5700 and it handled everything you're describing. Some generators list their surge as their capacity (or put the surge in BIG letters!).

    An important consideration when shopping for a generator is how you're going to wire it to your house. If you're looking at back-feeding and using an interlock it's important to buy a generator that is of a "floating neutral" design. Many portable generators have a bonded neutral and can cause problems when hooked up in this way (never knew it, never seen it, but I've heard about it and now I worry about it). For this type of generator (bonded neutral) you need a transfer switch that will break neutral as well as hot leads.
  4. EatenByLimestone

    EatenByLimestone Minister of Fire

    Joined:
    Jul 12, 2006
    Messages:
    4,822
    Loc:
    Schenectady, NY
    Get it sized to run one of them. Probably the well pump. Run it only when you need to refill your containers. Then start up the fridge/freezer to rechill it.

    You don't want it to drink all the gas that the generator would if you ran it constantly. You would be going through 20 gallons a day. For a week you would be storing an awful lot of gas.

    There are charts that you can use to calculate your usage. Pay special attention to the care that any medication or medical devices have. Keep in mind the gas usage of your generator and make sure you can run it for a week without power. Plan on only plugging in appliances once in a while when they are needed. They don't all have to be plugged in at the same time. The fridge can probably survive if plugged in for an hour a day.

    Matt
  5. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,026
    Loc:
    The island of Rhum Boogie
    I've got a 6000k genset that will burn about 1/2 gallon per hour to keep the lights, fridge furnace, lights, outlets and well pump running during the day. We usually will run for 4 hrs in the morning, shut down and then run at night. Typically 5 gallons will last the day.

    The hard part for the OP is going to be the hot water. Because its an electric hw heater, that's a big load. When I had a smaller genset I would shut down the boiler while taking a shower, because the combined load was a little too much for it when the well pump was running. I could get a couple showers before having to let the hw tank recover.

    Check the wattage on the tank. If its 4k or below you could possibly do the same thing.
  6. jharkin

    jharkin Minister of Fire

    Joined:
    Oct 21, 2009
    Messages:
    3,277
    Loc:
    Holliston, MA USA
    From what Ive read bonded are more common than floating in portables. Its assumed most of the time they will be running things on extension cords so you need to the reference to ground for safety. (Speaking of when you do use it with extension cords its a good idea to rig up a small grounding rod - most sets have a lug to wire one to).

    The few portables that can float often have a selector switch - Honda's for example do.

    You are not out of luck if you have a bonded neutral, you just have to lift it. On my genset, the white neutral lead from the outlet bank was jumpered to the generator shell behind the end cap, I just disconnected it an taped it off. One of these days I intend to put in a selector switch.
  7. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,026
    Loc:
    The island of Rhum Boogie
    I pulled mine off and ran a longer jumper down to the ground lug on the frame, so if/when I use it as a portable I can just reattach it. Right now it's capped off and out of the way. Generac (my brand) is quite specific that messing with it will void the warranty, and I always worry a little bit about modifying a listed product. If I was putting a system together from scratch I'd follow the rules, but I'm certainly NOT buying another generator or replacing the transfer switch over something so insignificant.

    I like the idea of a selector switch, but have read that it's iffy to have a splice in a grounding conductor.
  8. jharkin

    jharkin Minister of Fire

    Joined:
    Oct 21, 2009
    Messages:
    3,277
    Loc:
    Holliston, MA USA
    Your solution is simpler and more reliable BT... so simple I didn't think of it. duh. [my set is a Generac also]

    Your probably right about avoiding splices in the ground. You want the path to ground to have the absolute lowest resistance possible, so in case of a fault its the path of least resistance for current to flow.
  9. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,026
    Loc:
    The island of Rhum Boogie
    Trust me, I didn't think of it. I always cheat from the smartest person I can find.

    I'm sure a switch is fine, and probably less likely to be forgotten.
  10. BrotherBart

    BrotherBart Hearth.com LLC Mid-Atlantic Division Staff Member

    Joined:
    Nov 18, 2005
    Messages:
    28,050
    Loc:
    Northern Virginia
    I know squat about electricity. But these portable gennies with bonded grounds, how does that work? I only use them with cords, not into the house wiring.
  11. heat seeker

    heat seeker Minister of Fire

    Joined:
    Feb 25, 2011
    Messages:
    1,949
    Loc:
    Northern CT
    Some well pumps are 115V, mine is. My hot water is oil, so I can run the genny and take a shower without taxing the generator, which burns about ½ gallon per hour. I run the generator only when I need to pump up the well tank or run the oil burner for heat or hot water, or run the 'fridge.

    My loads are balanced across the 220, so the loads on the generator are fairly even across the phases.

    Unless I need to run the heat, I can run the generator on a gallon a day, since our lighting is with LED lanterns, which will run 150 hours on 3 "D" cells. We cook on the propane grill, or a propane camp stove.

    So, power loss is an inconvenience, but far from the end of the world for us. Most of our neighbors have generators, but the Yuppies next door just leave for elsewhere for the duration.
  12. DianeB

    DianeB Feeling the Heat

    Joined:
    Apr 26, 2012
    Messages:
    397
    Loc:
    Foot Hills of the Berkshires
    I probably need something in the 4,000 range. Would prefer it attach to the panel and perhaps would have to do this anyway for the well pump as that is not somehting I could just plug into the generator. Lived here for many years and the past couple are the only ones where power outages have lasted up to a week. Our governor threatening the power companies to have plans in place for these kinds of storms. Last year we had lots of tree crews in but no coordination with the line crews. This year, expecting more coordianation, but having a generator would be a plus
  13. jharkin

    jharkin Minister of Fire

    Joined:
    Oct 21, 2009
    Messages:
    3,277
    Loc:
    Holliston, MA USA
    Hey Bart... You probably know that in your house electrical system the neutral is attached to a center tap of the secondary winding of the utility transformer at the pole. The AC voltage coming out of the xformer floats and its possible that the neutral could give you a shock if we didn't have a way to hold it at the same zero volt level of the house grounding system. Bonding the neutral to your local ground at the service panel does that.

    One very important point is you only ever bond the neutral and ground at one point in the system. Otherwise neutral return current can potentially travel on the bare ground wires back to the panel.


    The AC output of a portable generator floats just like the output of the mains transformer. Most portables have a grounding lug on the outlet panel that grounds the entire frame, the ground prongs of the outlets are also attached to the frame. Then the neutral output of the generator is also bonded to the frame at some point. (so neutral and ground are at the same "zero volt" potential).

    Ideally you should attach that grounding lug on the generator to some actual "ground" when its in use as a portable. For mine I rigged up a small ground rod from a piece of welding rod with a length of heavy gauge wire (#10 solid) soldered to it and then bolted to the ground lug. I tap it in the ground with a hammer when I run the genset as a portable. I keep the neutral bonded

    When I use the genset via the house transfer panel, the 4 wire attachment cable connects the generator ground and neutral to the house ground and neutral in the main panel. I unbond the ground at the gen now since now so we don't get 2 bonding points in the system. In this setup its not critical to use the generators grounding rod either since its tied to house ground.
  14. btuser

    btuser Minister of Fire

    Joined:
    Jan 15, 2009
    Messages:
    2,026
    Loc:
    The island of Rhum Boogie
    I just found out about this, so I'm a 30-minute expert:

    When using a portable generator with cords you WANT the bonded neutral, especially if you'v got GFI outlets because otherwise it may not work properly.

    In the NEC electrical code it's a kinda cardinal rule that the neutral (grounded conductor) is bonded with the ground (grounding conductor) ONLY at one place, and that's usually at the service entrance. Exceptions? Always, but for the most part you don't do it. All sub panels need to have their grounds and neutrals separated all the way back to the main panel. This is to eliminate the chance of "objectionable current loops" through the neutral which can affect electronics, energize conductive parts/enclosures and even cause fires. Once again, this has the potential to screw up GFI and arc-fault breaker protection.

    The problem begins when you hook a bonded neutral genset into a transfer switch (like Reliance or Gentran) that break-before-make only the hot legs and do not break the neutral of the circuit. When you plug in your generator you inadvertently make a second neutral bond connection away from the main panel and that's a no-no. By code you should be breaking the neutral and hot legs for all circuits served by a generator, but apparently it's perfectly safe to use with a "floating bond" generator that doesn't break the circuit neutrals.

    Generac (my brand) doesn't want you messing with their appliance, but they're nice enough to label this jumper for me, and quote a bunch of Canada electrical codes. This is the moment when I call BS, and look for a workaround. I found the neutral bonding jumper, did the unthinkable (by thinking) and altered a UL listed appliance thus voiding the warranty. Now the frame of the generator is grounded through the house grounding conductor when used in standby service, but the frame is NOT grounded in this condition when unplugged from the house, so if a motor winding or something shorted out it could energize and be dangerous. As soon as I shut down and unplug I make sure to reconnect the bond.
  15. jharkin

    jharkin Minister of Fire

    Joined:
    Oct 21, 2009
    Messages:
    3,277
    Loc:
    Holliston, MA USA
    The thing I worry about is with the neutral and ground boned at both panel and generator, the return current could follow the ground path back to the generator (in fact it would be more likely to go that way if the ground is heavier guage and lower resitance than the neutral lead in the generator cable) before jumping to neutral there, resulting in energizing the frame of the genset with current.

    I

Share This Page