Fuse questions

[jbing81]

Hi Guys

I had to go through and rewire a few electrical items I have on the boat and have a few questions as to what amp fuses I should use.

To start I have run 8ft of 10g from the bat (+) to the fuse block and about a foot of 10g for (-). from there I have run 16g from the fuse block to all electrical items

17ft for running lights
3ft for the vhf
3ft for AM/FM
12ft for bilge (which is already up and running on a 2 amp fuse)
and I plan on running a dedicated 10ft line for a cig. lighter on a 10g line with a 15 amp fuse only because I ran out of room on the block.


So now that you have the background...

Ive checked the maunal that came with my vhf and couldnt come across the fuse reccommendation for my model. Its a Cobra MR F45.

Also what is the fuse reccommendation for running lights? I only have 2 bulbs, bow and stern.

Any help would be great!

Also, if anyone has any conceerns with what Ive done so far with the electrical please let me know.

Jeff

 

[fish_on_the_deck]

Re: Fuse questions

Fuses are to protect the wiring not the equipment it is supplying. The device should have an internal fuse to protect it. So since you used 16AWG, which has a max current rating at 18A at 90 degrees C (link), a 15A fuse should be the highest you would use. You obviously could use a smaller fuse if you want, but if you get too small you might blow it without wanting to, and if there really is a short circuit fault scenario, it will definitely blow the 10 or 15A fuse and still protect you.

If you need to figure out how many amps a load draws divide the watts (if you know it) by the voltage (12V in small boats). So if your lamps have 30W bulbs thats 2.5A.