And a honkin' big pump as well as I noted elsewhere. The actual pump is
unlikely to be > 2 hp if this is just a residential well. I don't have
a clue as to why it would be on a 40A circuit unless there's another
branch circuit feeding the pump itself or it is, in fact, a much larger
Not true. We have a 3 HP well pump (750 foot deep well), and also a 3
HP pressure booster pump (required because our county requires fire
sprinklers inside the house, so our pump hast to make 50 gpm at 60
psi). One of our neighbors has a 5 HP pressure pump (larger house,
more sprinklers). Admittedly, such large pumps and such deep wells
are somwhat rare in a residential setting, but not unheard off in
areas where the aquifer is deep underground.
That is the big question here. With a 40A circuit, it could be a 5 HP
well; starting that on any consumer-grade inverter is not possible.
There are inverters that can do it (typically used for people who live
off-grid, using wind turbines, solar cells, and big battery banks);
expect to pay 5-figure $$$ amounts for them.
But a 40A circuit could also mean that it is a really small well pump
(1 HP maybe), and a clueless electrician, or an amateur electrician
who likes to overengineer things. The really scary thing might be
that it is a 40A breaker found in the parts bin, feeding a 15A circuit
using 14 gauge wire and a 1 HP pump. I suggest checking out what the
heck is going on (size of pump, current draw, size of wiring) before
making any dangerous moves.
NO DON'T TRUST THAT. You can only trust the circuit breaker size, if
you are 100% sure that the circuit breaker was installed by a
competent electrician, using the usual rules of thumb, and not
modified since. It would be legal (but wasteful and unusual) to use a
very large circuit breaker and very large wiring for a small well
pump. It is unfortunately common for people to use oversize breakers,
for example for emergency repairs. Standard joke: The 15A breaker
kept tripping, so I put a 40A breaker in, and it didn't trip any more,
instead my house burned down.
Example: One of our neighbors just discovered that his 3 HP well (30A
240V breaker) had been wired by the previous owner using underground
feeder cable, with 12-3 cable (two 12-gauge hot conductors, neutral,
and ground). This is slightly wrong, because the neutral is useless.
And it is dangerously wrong, because a 12-gauge cable can't handle
30A, in particular not on a 1000-foot run. Fortunately, our neighbor
noticed it, not because the cable fried or the house burned down (this
setup had been used for about 20 years without problems), but because
he was digging a hole in another place, and unexpectedly tore the
cable up (it wasn't buried where one would expect it). It first
sparked a bit, then it stopped sparking, the well stopped working, and
the 30A breaker popped. Very strange, isn't it. That neighbor is
currently busy digging a new trench, laying conduit, and installing
8-gauge wire for his well.
The address in the header is invalid for obvious reasons. Please
reconstruct the address from the information below (look for _).
First thing you need to know is the starting current and run current of the
well pump. The amperage can be used to calculate the wattage needs of the
Second, a Coleman generator (about 5000 watts) can be had a the discount
houses for about $500. And does have a 220 volt outlet on it.
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