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Well pump tripping GFCI

chl

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Indeed but this number ignores the time, either your own experienced time or an expensive electrician, to route circuits from the main breaker to the transfer switch breaker. I had thought the isolation transformer was a good solution, if it does whole house, because it would skip that re-wiring and be cheaper than more expensive transfer switch after you added man-hours.

But all of this is moot for me, I already have the transfer switch, yet it doesn't handle the pump, so I shall get the transformer installed and be happy with everything working.

I think my electrician was a little scared of this new idea and went a little overboard on the hardware but it worked out in the end (minus the well pump).
It looks like a 240VAC 30A transformer (7.2kVA) would cost in the neighborhood of $1700 and up, and would have to be wired to the house as well.

Wiring a transfer switch like the GENERAC 6853 should not cost too much.

Yes, it looks like you have a big Seimens disconnect/transfer switch and a whole separate breaker box too. Definitely on the expensive side compared to a GENERAC 6853 install.

Although the GENERAC manual is a bit obtusely written, basically the wiring is take the hots and neutrals from the circuits you want to back up and connect them to the corresponding hots and neutral prewired in the transfer switch. You also install a 50A breaker in your main service panel and power to the transfer switch when the utility is on (to power the backed up circuits from the utility).
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admo

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It looks like a 240VAC 30A transformer (7.2kVA) would cost in the neighborhood of $1700 and up, and would have to be wired to the house as well.

Wiring a transfer switch like the GENERAC 6853 should not cost too much.

Yes, it looks like you have a big Seimens disconnect/transfer switch and a whole separate breaker box too. Definitely on the expensive side compared to a GENERAC 6853 install.

Although the GENERAC manual is a bit obtusely written, basically the wiring is take the hots and neutrals from the circuits you want to back up and connect them to the corresponding hots and neutral prewired in the transfer switch. You also install a 50A breaker in your main service panel and power to the transfer switch when the utility is on (to power the backed up circuits from the utility).
I still think the isolation transformer would be cheaper. You left out all the breakers you must buy and add to the Generac box, I thought those are like $50 each. Plus that time fishing wire around breaker boxes is not free. The isolation transformer Maquis linked was $700 and I presume the install is much simpler as well as implicitly power the whole panel.

The only downside I'm seeing to the isolation transformer is the power loss people talk about but I have no idea what that loss is in practice.
 

Maquis

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I still think the isolation transformer would be cheaper. You left out all the breakers you must buy and add to the Generac box, I thought those are like $50 each. Plus that time fishing wire around breaker boxes is not free. The isolation transformer Maquis linked was $700 and I presume the install is much simpler as well as implicitly power the whole panel.

The only downside I'm seeing to the isolation transformer is the power loss people talk about but I have no idea what that loss is in practice.
Typical operating losses are 3 to 5% for small dry type transformers. Look for an efficiency curve or data sheet before you purchase. Your electrician can help interpret the data.
 

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Wouldn't replacing your well pump with the appropriate sized Grundfos be the best and least expensive option?
 

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admo

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Yikes. Must be a big ass pump. The 3/4 hp Grundfos installed at our off grid place was like $750 in 2015.
They appear to be ~$2,000 for a 3/4 hp one now. Also have to run the four different copper wires down a 380 foot well, so a lot of copper. And just professional time.

But these numbers are for my situation at 380 feet, I know pumps get exponentially more expensive as you increase their head lift (depth). If you can pump water out from less than 50 feet I bet it is cheap enough to make that option viable.

Part of the wiring cost was them telling me 30 year old copper wire is not up to code anymore, so if they pull it up they have to replace it even if they send the same pump back down. I would be more worried but we had the water tested a year ago so I'm not worried about leaching, although I don't know why the wires are not up to code anymore.
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