More backup generator discussion: Backing up well pump in a different structure

[EarPlug]

A little off topic but you should consider running some data cables between the 2 locations while the trench is open.

 

[CobyRupert]

I presume the well pump is powered from the panel in the existing house. I would consider removing it from that panel, and instead connecting it to the panel in the new home with the generator backup. To do this you need a "home run" direct electric line from the new house to the well pump, bypassing the existing house entirely.

If you do this, your standby emergency generator only needs to heat up the panel in the new house which includes a breaker for power to the well pump.

I would not try to have the generator heat up two separate panels in two separate residences-- seems like way too many things to go wrong.

Do-able, but "permanent" voltage drop issues should be avoided, more than temporarily issues when the genny is running at the new house. Plus if the old house becomes an office, with tax write off "business expenses", keeping the pump on it's meter may have advantages.

As far as one genny feeding power to 2 residences, one has to pay attention to the fact neutral & grounds are bonded at each residence's panel, and you don't want your genny circuit connecting the 2 neutral/ ground systems. i.e. you'd have 1 connected system (when in "emergency" mode) with 2 ground/neutral bond locations. Ground and neutral should only be bonded at 1 location.
Thus you want your transfer switch at the old house to be 3 pole (2 hots, 1 neutral) to not only transfer the circuit(s) power at the old house, but to also transfer the circuit(s) neutral of the genny powered loads to the neutral from the genny (which is bonded to ground at the new house's panel). The transfer switch at the new house would NOT switch the neutral. That is: the transfer switch in the old house should isolate and switch the neutral of the pump (and other genny powered loads) from the old house panel's neutral bus and connect them to the neutral coming from the genny (and new house) when in emergency mode.

Seems like you'd want the transfer switch/panel in the old house to be able to run the heat (controls) as well as the pump. and maybe a few light/power circuits. Load management may be required.

 

[RSKY]

I am a bit of a cheapskate so I have to ask. Aren't you spending an awful lot of money for a two hour outage? For two hours we can rely on bottled water.

Just asking.

RSKY

 

[wagne223]

I like redundicy, I have 2 HVAC system on a house that only needs one. I have 3 generators, 2 freezers, ect.

If I were in this situation, I would install another well for the new house and run a pipe between the houses with necessary valves to feed both houses from either well in the event of a failure.

I would keep them independent and only tie together in an emergency.

Around here, a 4" well with pump and 80 gal tank is around $4500.
Not unreasonable if you are building a new house.

I do understand that wells can be considerably higher depending on geographic location. And this option may not be feasible for everyone.

It would definitely solve your backup power issue though!

 

[Valveman]

I agree a spare well would be nice. Generator at new house with "home run" wire to the pump at the old house will work. You can be out of power and turn the gen set on. But even when you have power pumps always quit on holidays and weekends. Always nice to be able to turn on a spare well until the snow melts or you have time and equipment to fix the main well.

A cistern storage tank and booster pump will give you a day or two of water, but a spare well will keep water running as long as you have power from the grid or the gen set.

 

[Ford850]

I don't understand how a home run wire from the new house to the well will help. Isn't the well pump currently powered through the pressure switch in the old house, at the pressure tank? The new house would need a wire feeding directly to the pressure switch in the old house.

 

[Jcoon]

Do-able, but "permanent" voltage drop issues should be avoided, more than temporarily issues when the genny is running at the new house. Plus if the old house becomes an office, with tax write off "business expenses", keeping the pump on it's meter may have advantages.

As far as one genny feeding power to 2 residences, one has to pay attention to the fact neutral & grounds are bonded at each residence's panel, and you don't want your genny circuit connecting the 2 neutral/ ground systems. i.e. you'd have 1 connected system (when in "emergency" mode) with 2 ground/neutral bond locations. Ground and neutral should only be bonded at 1 location.
Thus you want your transfer switch at the old house to be 3 pole (2 hots, 1 neutral) to not only transfer the circuit(s) power at the old house, but to also transfer the circuit(s) neutral of the genny powered loads to the neutral from the genny (which is bonded to ground at the new house's panel). The transfer switch at the new house would NOT switch the neutral. That is: the transfer switch in the old house should isolate and switch the neutral of the pump (and other genny powered loads) from the old house panel's neutral bus and connect them to the neutral coming from the genny (and new house) when in emergency mode.

Seems like you'd want the transfer switch/panel in the old house to be able to run the heat (controls) as well as the pump. and maybe a few light/power circuits. Load management may be required.

I have 2 panels at my house, one in the house, one in the garage, I backfeed through the garage, both panels are bonded because I have 3 wire service, what’s the issue?

 

[Larry Caldwell]

Are you married to the idea of two separate meters? Another option is to just install a single 400a service, with 200a breakers to each house and a transfer switch on the main panel. That way both houses and the well have generator backup, and you only get a bill for one electrical service.

 

[rbstern]

A little off topic but you should consider running some data cables between the 2 locations while the trench is open.

Yep. Plan to put three Cat 6 cables in the trench.

 

[CobyRupert]

I have 2 panels at my house, one in the house, one in the garage, I backfeed through the garage, both panels are bonded because I have 3 wire service, what’s the issue?

Don't want to distract too far from OP's question, but is one of your panels sub-fed from the other; this is very different than having 2 meters.
If sub-fed, only the main panel should have ground and neutral bonded with each other. The ground bus should be isolated from the neutral bus (green wires separated from white wires) in the sub-fed panel.

The issue/problem if ground and neutral are bonded in 2 places is the ground and neutral conductors between those 2 places are now essentially parallel conductors connecting the same points: so that the neutral current is split with some running through the (green) ground conductor. The problem with this is ohms law. A current running through a conductor (that has resistance) will create a voltage across that resistance (conductor), this is a problem because everything connected to the (green wire) ground conductors should be at 0 volts (grounded). These are things people touch. So now, because current is flowing on the ground conductor, everything people touch (metal enclosures, equipment cases, etc..) connected to the (green wires) ground has a voltage NOT zero. This could be a shock hazard (though most likely just a little trickle). A bigger problem becomes if a neutral or ground connection then fails and the whole ground system (and metal cases connected) goes to 120V.