Low Volt / Low Amp - Boat Lift Motors

casey344

We are dock contractors in SC.

Customers of ours who are too cheap to have professionals like yourselves run electrical between their home and dock run their boat lifts motors off of drop-cords run from the closest outlet.

This seems to cut the life of what would normally be a motor that lasts 20 years to about 2-3 years. When the motor fails they call wanting to cash in on a warranty.

The motors are A.O. Smith 110V and draw 6-8 amps (while running), installed properly they are installed alone on 20 amp breakers.

I'm looking for a clearer explanation to tell our customers, something a little more in depth than drop-cords are bad. Can you help?

Is there a way to tell the difference between a motor that simply failed because it was bad and one caused by a drop-cord install?

mickeyco

Are you (your electrician) accounting for voltage drop?

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casey344

We aren't accounting for anything.

We install the lift, test and lube it by hooking it to a 7500W gas generator and tell the customer to call their electrician.

Someone from our office looked at the motor yesterday, here is the info I received:
"I looked at Daly’s lift yesterday and it has been run off an extension cord since it was installed. He has a 220 circuit run down the hill to the pier and then an outlet to plug the cord into. I tried to find the wire size for the circuit coming down the hill but the wire jacket was too weathered to read. It does look on the small side for the distance it is running."

House to dock is approximately 300'. At 220V our lift manufacturer recommends a #6 wire.

Casey

mickeyco

When you said "Low volt / low amp - boat lift motors", I was thinking a small 120 V geared motor. I was thinking a long run and a voltage drop problem, it may still be a voltage drop problem. But that's a long run run and there's going to be some other requirements, a disconnect, a GFCi breaker and ?. Are you saying that it's a 300' extension cord? I'd wait for the electricians here to give you a bit more info.

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__________________
Some people climb mountains. I take out the trash. But we both do it for the same reason.

CNC

Was the motor that just failed, 220v or 120v? im confused.

casey344

They can be wired either way ... this one apparently was 220V.

Speedy Petey

Voltage drop is the issue. This is due to too small of a wire at that distance and also the cord ends are not up to the task of that load, for that long, in those conditions.

If you want an opinion, I'd put it writing in your contract with these folks that if the lift is run off an x-cord ALL electrical warranties are void. PERIOD.

It KILLS me that folks who can afford water front property, and a dock with a boat lift, are that cheap (read: STUPID) to have a job done properly by a professional.

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casey344

Great ... thank you for the feedback.

How does the voltage drop over time kill these motors? Or does it?

CNC

Inductive loads, (like a motor), will overheat if its not supplied with the correct voltage. I like the idea of writing it your contract, this seems like its not the first time.