Electric Water pump - should I fuse the circuit?

[Mdfatsi]

Today, a hot day in Virginia, the fuse on my (Davis-Craig) water pump circuit blew causing the pump to stop working. Well the car over heated pretty quickly before I realized what happened. Hopefully serious damage was averted- too soon to tell.

The question I have is how many of you out there are running the pumps through a fused circuit> After today I'm thinking of running the pump straight without a fuse.

-Michael Fatsi
Richmond, Virginia

[SaphireSpud]

Warning light after fuse? Regards, John.

[barkerwilliams]

A fuse blows because the current passing through it exceeds its rating. So why did it blow, it there a fault or was the fuse incorrectly specified for the circuit. Any circuit running at its maximum for some time will cause a heat build up in the fuse until pop the fuse goes out in a blaze of glory. (or ignominy)

Could I suggest that a modest increase in the fuse rating would be no bad thing unless you have reason to believe something is amiss, if so then removing the fuse would be an excellent reason to buy an in-car fire extinguisher and check the small print on your insurance policy.

Alan

[trunt]

To answer, yes I have the supplied online fuse in circuit. The Davis Craig has a warning light, do you have it wired in? did it light? Not sure but maybe it would as there is 12v unfused ign. supply to the unit as well..

i asked Davies Craig about that.. will report back.

[trunt]

Scratch that warning light idea... it uses the fused supply so could not light.

I did find that the 115 pump draws 10A max so a 15A fuse is not unreasonable.

[fussydave]

Under no circumstances should you be fitting a fuse that is not of the type and rating that is recommended by a component manufacturer or a circuit designer. There is no doubt that the Davis Craig wiring is not designed to carry a 30 Amp load so do not fit a 30 Amp fuse as has been suggested. I would suggest that the correct fuse may be a surge protection type rated for the circuit cable size and expected load. Such a fuse would handle any initial surge in current when the pump starts but would protect the circuit if an overload or short was to occur.

Fundamentally though, why has the fuse blown? This needs to be ascertained, and until proven otherwise it should be assumed that the fuse was correct and that there is a fault in the circuit. You say that the car overheated. Did it overheat as a result of the pump stopping or was there a failure in the cooling system that caused the car to over heat and possibly over heat the pump or starve the pump of coolant causing it to seize? Has the pump wiring been damaged, has the control unit failed? All needs to be checked.

Dave.