# Will an ammeter register a motor's startup surge?

**URL:** <https://boards.straightdope.com/t/will-an-ammeter-register-a-motors-startup-surge/804955>\
**Category:** Factual Questions\
**Created:** [December 20, 2017, 10:37pm UTC](https://boards.straightdope.com/t/will-an-ammeter-register-a-motors-startup-surge/804955 "2017-12-20T22:37:59Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![boytyperanma](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@boytyperanma](https://boards.straightdope.com/u/boytyperanma)\
**Post date:** [December 25, 2017, 8:59pm UTC](https://boards.straightdope.com/t/will-an-ammeter-register-a-motors-startup-surge/804955/21 "2017-12-25T20:59:44Z")

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> [@Nars\_Glinley](#):
>
> It’s a 3 wire 220 with a double 20 amp breaker. The “first water” in this area is around 25 feet. I’m guessing that the pump is around 60 feet. I can’t imagine that it’s more than 1/2 hp.

If it’s a 3-wire motor there is a control box that will say the hp right on it. Three wires will have red, black and yellow wires. A newer 3 wire has 4 wires die to the additional green wire.

A 2-wire has red-black and sometimes a green as well.

1/2 hp pumps make up the majority of my residential installs, about 70%. Average well depth for my area is 200ft. Static levels average 15ft but wells aren’t always high yielding so the pump pulls the water level down while running.

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**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\
**Post date:** [December 25, 2017, 9:31pm UTC](https://boards.straightdope.com/t/will-an-ammeter-register-a-motors-startup-surge/804955/22 "2017-12-25T21:31:06Z")

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Then I misunderstood. Mine is red-black-green. No control box. Just the electrical box and the pressure switch.

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**Author:** ![ctywkr](https://avatars.discourse-cdn.com/v4/letter/c/ecb155/32.png) [@ctywkr](https://boards.straightdope.com/u/ctywkr)\
**Post date:** [December 26, 2017, 4:09am UTC](https://boards.straightdope.com/t/will-an-ammeter-register-a-motors-startup-surge/804955/23 "2017-12-26T04:09:29Z")

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> [@Nars\_Glinley](#):
>
> It’s a 3 wire 220 with a double 20 amp breaker.

So 220 volts and 20 amps. 220 X 20 amps=4400 watts.

If all you want to power is the well pump 5000 watt generator.

If it works with normal power, it will work with a generator.

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