Fuse in Bilge Circuit?

[Grant Brown]

I have a 1972 Glastron with a 1987 Merc 70.
I have been cleaning up the wiring and found an in line automotive fuse in the bilge circuit. I am wondering if it's even necessary. I taped it up good but since I run in salt all the time it looks like a real strong potential for corrosion.
I am concerned about the possibility of corrosion and then failure when I need it most. I also think that if I really need the pump to run hard for an extended period then it would be smart to NOT have the fuse to protect the pump. I'd rather run the pump til it melts and destroy the pump to save the boat.
I like all my connections soldered then heat-shrinked and this looks mickey mouse to me.

Any comments?

Thanks,
Grant

 

[dingbat]

Re: Fuse in Bilge Circuit?

If you are running an automatic bilge pump chances are that the pump is wired directly to the batteries so you need a fuse there for protection.

If it?s some cheap automotive holder then change it out for a good quality marine holder. The fuse in my in-line holder looks as good as the day it was installed.

Better to flip the switch and have nothing happen than to look back and see the back of the boat on fire.

 

[Grant Brown]

Re: Fuse in Bilge Circuit?

It's not automatic. There are 12ga wires running to the helm.

 

[Silvertip]

Re: Fuse in Bilge Circuit?

The bigger the wires, the bigger the fire. Fuses protect the "circuit". If you run without a fuse in that circuit and a short develops in those 12 gauge wires you have the equivalent of a cheap electric welder. Ever touch a wrench across the battery terminals on your car or truck. Makes big sparks right? Ever see a wrench "stuck" to a battery and nearly glowing? You don't want that situation on a boat. Fuse it properly or add a circuit breaker.

 

[dingbat]

Re: Fuse in Bilge Circuit?

It's not automatic. There are 12ga wires running to the helm.

You'll have wires running to a 2 or 3 position switch on the helm even with an auto switch.

Not having the pump setup for automatic operation would worry me a heck of a lot more.

 

[littlebookworm]

Re: Fuse in Bilge Circuit?

Most boats I've seen have a 3-way switch, manual, off, automatic. The 3 boats I've owned all had a fuse at the helm to protect the circuit but out of harm's way of salt water. Check at the helm for a fuse and a switch. If neither is there, you might consider adding both. That way, the circuit's protected and you can turn on the pump when you want to clear up the little amount of water that might not trigger the float switch.

 

[Grant Brown]

Re: Fuse in Bilge Circuit?

Thanks for all the thoughtful replies. That's why I keep coming back to iboats - good advise.
I plan to add an automatic float switch to the pump, and move the fuse to the helm under the dash near the switch.
What is an acceptable size fuse for a bilge pump (it is the only load on the circuit)?

Grant

 

[Silvertip]

Re: Fuse in Bilge Circuit?

Fuse size is determined by the current draw of the pump and that depends on the size of the pump. More GPH = higher current. That number is found on the package or the pump housing. Go 10% higher on the fuse or simply use what the instructions tell you. Just make sure the wiring is capable of handling that current or the fuse will be worthless.

 

[dingbat]

Re: Fuse in Bilge Circuit?

You may want to reconsider moving the fuse from its present location.

In order for a fuse to work it must be between the short and the battery. If you put the fuse at the helm a short in the wire running from the battery to the helm could have dangerous consequences. Especially since the wire would most likely be buried under the deck and your first indication of the problem would be smoke.


You might want to read this as well

http://www.boatus.com/boattech/casey/14.htm