Swamp cooler water pump ground

The ground pin of the swamp cooler water pump A/C plug pulled out when I unplugged it to lubricate it for the summer so I have to buy a replacement plug. Being cheap, I deeply regret this expense.
My reason for posting: Why would this pump need a ground? It's plastic covered so no personal shock danger. Probably because it operates in such a wet environment. But still, what is it protecting? I'm stupid, obviously.
TIA
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"Where there's smoke there's toast!" Anon






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wrote:

You mean the pump becomes defective, shorts to the water flow, which carries the electric current to the cabinet, which is then is dangerous to touch? Maybe. But I'd think the cabinet would be grounded elsewhere, perhaps though the blower? Might be interesting to check that with an ohmmeter.
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On 3/18/2013 1:06 PM, KenK wrote:

May be, but perhaps it's mounted w/ isolating feet to minimize noise/vibration??? Who knows w/o looking/more detail?
But, my guess is that it was an off-the-shelf production pump and it was simpler to just use the supplied 3-prong plug than rewire it and cheaper than specifying a built-to-purpose pump.
It may be there's a UL (or similar) listing requirement that the motor has to be grounded anyway even if it is direct mounted to the frame just to protect against the possibility of that ground connection via the mounting bolts being violated.
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when

plastic

stupid,

dangerous

elsewhere,

Cabinet is grounded.

was

cheaper

Quite possible.

just

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"Where there's smoke there's toast!" Anon






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when

plastic

Neither. A window unit in a mobile home.
BTW, checked with meter and cabinet is grounded.
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On Monday, March 18, 2013 9:42:34 AM UTC-7, KenK wrote:

Because the plastic doesn't make it 100% waterproof, as a totally submersible pump would be. The metal motor case must be earth grounded.
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snipped-for-privacy@my-deja.com wrote in

Ahhh! I think you may well have hit upon the reason. Thanks.
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snipped-for-privacy@invalid.com says...

There may be metal parts inside which should be grounded. A short to those metal parts could conduct electricity to the water or the plastic exterior if wet.
In addition to the pump being grounded, you would also want the fan motor and metal case grounded.
The more things which are grounded, the safer for you and your family! (And anyone who touches a metal vent... Roof vent connects to house vents, house vents connect to floor heating return vents, kid crawls up to wall and touches floor vent - ZAP!)
Buy the proper plug!
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