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

[rbstern]

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

When Irma came along, we were surprised at how long it took the county and local EMC to get everyone back online. Also, for outages where power is down but phone is up, I can still be connected to the Internet for my work, and sometimes my responsibilities to my clients are urgent enough to bear the expense for backup power.

 

[MossRoad]

Since you have two meters, is it legal to run wiring between the two to run them both off of one generator?

If yes, you could probably run a feed between the two, and use a kirk key setup for lockout of utility power before being able to feed the old house from the new house.

KIRK(R) - The Leader in Trapped Key Interlocks

These were suggested a few years ago by member Aczlan in another generator thread. They seem like a really simple, yet elegant solution.

Put a kirk key in the old house to make it switchable between utility power OR new house power. It can't be fed from both at the same time due to the key. It's an on-off-on arrangement. No possible way to mix feeds.

 

[rbstern]

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!

Wells around us are typically 200 to 300' deep. Doubt that could get done for $4500. It's a possibility.

 

[rbstern]

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.

You are correct.

 

[Jcoon]

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.

I have a main panel out front, and a panel in the house and then A panel in the garage, all are neutral ground bonded. All are fed by 3 wire. 2 ground rods at each.

 

[Jcoon]

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.

Obviously that痴 what where all saying is power the pump by the new house with a wire in the new trench.

 

[rbstern]

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.

I could live with that solution. The only downside I can think of is, when we're dead and gone, somebody may want to sell this property as two homes. But I suppose that's not really any more problematic than both homes being on a single well.

I'll ask the power company engineer to weigh in on this when he/she comes to the property.

 

[CobyRupert]

I have a main panel out front, and a panel in the house and then A panel in the garage, all are neutral ground bonded. All are fed by 3 wire. 2 ground rods at each.

I assume the main panel feeds the house and garage panel. By code, the ground and neutral should only be bonded with each other at the main panel, and isolated from each other in the sub-panels.
While not to code, what helps in your case is the ground rods at each panel keeping "ground" close to 0 volts even though (normal) neutral current may be flowing on ground conductors.

Neutral current should only be on (white) neutral conductors.
Ground conductors (green) should have no current on them.
It's against code for neutral current to run on ground conductors.

 

[CobyRupert]

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.

Yes, it's assumed "power to the well or pump" means through the pressure switch, regardless of where the power source is.

 

[Jcoon]

I assume the main panel feeds the house and garage panel. By code, the ground and neutral should only be bonded with each other at the main panel, and isolated from each other in the sub-panels.
While not to code, what helps in your case is the ground rods at each panel keeping "ground" close to 0 volts even though (normal) neutral current may be flowing on ground conductors.

Neutral current should only be on (white) neutral conductors.
Ground conductors (green) should have no current on them.
It's against code for neutral current to run on ground conductors.

Well mine is to code it was inspected this summer of 17 by two different electrical inspectors. Again I do NOT have a 4th wire ground wire going to my panels connecting them.