dpb wrote in :

On 3/18/2013 1:06 PM, KenK wrote:
wrote in
:

On 18 Mar 2013 16:42:34 GMT, wrote:


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

I'd guess something to do with the cabinet being metal, potential for
shock. (SWAG)


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.

May be, but perhaps it's mounted w/ isolating feet to minimize
noise/vibration??? Who knows w/o looking/more detail?

Cabinet is grounded.

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.

Quite possible.

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.

--





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