In article ,
Duane Bozarth wrote:
I'm still curious as to why a residential well pump is on a 40A circuit?

Maybe because his well is very deep? Our well is 750 feet deep, and
has a 3HP pump (14.5A when running) on a 240V 30A circuit. I have
heard of people in the area with 1000 foot deep wells using 5HP pumps;
those would require either 40A or 50A circuits.

Or maybe because he needs lots of water? For example, in our area the
county requires a well to yield 3 GPM before they will permit
construction of a house. If the house has a lot of landscaping that
wants to be irrigated, a small holding tank, and a really good well,
then a 5HP well pump is the cheapest way to get enough water quickly.
A big set of yard sprinklers can run through 30 or 50 GPM in a hurry,
and some wells will give you that much water, but you need a serious
pump to move that water around.

Or maybe because the person who built the circuit had no clue, or had
parts for a 40A circuit sitting around, or was planning to add other
loads to the circuit later (whether legally or illegally is another
question). Or maybe the circuit was planned with addition of a larger
well pump later on in mind.

You are right: For the typical east coast / midwest aquifer (which
often needs a 30 foot driven well with a 3/4 HP jet pump), a 40A
circuit is quite ridiculous. Once you are into deep well with
submerged pumps (common in the west), the situation is different.

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