what size fuses?

[bodieb20]

okay so I'm going to run 8 gauge wire from my battery to my fuse panel and then probably use 16 gauge to each of my devices. What size fuses should I use for nav lights, a fish finder, and bilge pump?

 

[YN2(SS)]

Re: what size fuses?

Bodie,
Im faced with a very similiar situation. I have a 89 Sylvan 21' bowrider and I have to replace the ignition switch, all the panel switches as well as the circuit breakers. I have been looking on here and cant find any sort of guide so far as to what to use for the nav light circuit or courtesy light circuit that I have, but I have found info on the box for my blower saying it requires a 6 A breaker/fuse and my bilge pump which requires a 2 1/2 A breaker/fuse. That is where I am starting to build the info. If you find anything on here that is solid info, let me know. When I look at my boat tomorrow, I will look to see what the old breaker/fuses are and use them as a guide.

 

[Silverbullet555]

Re: what size fuses?

Keep in mind what you are fusing. If you are fusing the 8 gauge within 6" of the batteries as you are supposed to then you are fusing the wire and not the devices. Find the capacity of the wire and you know the max fuse size.

 

[colbyt]

Re: what size fuses?

I saw this post yesterday and did not reply since I have no real information to offer.

I can offer a few tips to help you out. As YN2 posted some items will have a label and that should be your guideline for those. Be sure to match the short wire runs to the fuse size used. Lights and stuff you can most likely compare the the wattage to what is in you car an use the same size wire and fuse. If in doubt use a larger wire that you guesstimate along with an inline fuse holder so that you can safely increase the fuse size if necessary.

My old fish finder has a rather small wire and I suspect they all don't pull much power.

 

[NYBo]

Re: what size fuses?

The purpose of the fuses in the fuse panel is to protect the (16 gauge) wiring, so 5 to 10 amp fuses will be fine unless any of the devices draw more than that. The bilge pump would be the only one of the devices you listed that might draw more than 5. The fishfinder will draw less than 5 amps, so you could go smaller to prevent the smaller wires from frying and causing a fire.

 

[MH Hawker]

Re: what size fuses?

The 8 gage main is 50 amps depending on how long the run is and yes it should be fused at the battery.

 

[bodieb20]

Re: what size fuses?

yea the 8 gauge wire will only be ran 2ft maybe? And I know 8 gauge wire is kind of big for this situation but I would rather be safe then sorry. And okay I figured the fuses would need to be bigger then that for that 16 gauge but thanks for the advice! I love iboats people are always willing to help.

 

[MH Hawker]

Re: what size fuses?

Try to remember fuses are to protect the wiring not a device so 16 gage will handle a max of 10 amps, so that allows you to use smaller fuses for the device and still be safe.

 

[Silverbullet555]

Re: what size fuses?

yea the 8 gauge wire will only be ran 2ft maybe? And I know 8 gauge wire is kind of big for this situation but I would rather be safe then sorry. And okay I figured the fuses would need to be bigger then that for that 16 gauge but thanks for the advice! I love iboats people are always willing to help.

Here is how I fused my ACR when I did it.

I already had a switch that was factory. I added the second battery, used the blue sea add a battery set up including 2 battery switch and made my own cables using a hydraulic crimper, marine ring terminals and marine shrink wrap with adhesive.