Best Location for In-line Fuse?

[JSU Fishing]

I will soon be pulling new wire for both graphs, using tinned 14 ga. wire, independent runs for each unit, directly to the battery, with both using the same disconnect switch at the battery. The question I have is where I should put the in-line fuse. At the disconnect would be most convenient for troubleshooting, if there was a problem, but is it possible that with the larger wire size, I could potentially be sending too much amperage to the unit downstream from where it transitions to the 18 or 22 ga. wire that plugs into the unit?

[bobcoy]

Fuse at the battery to protect the whole wire. Larger wire is reccommended. Many are using #10 and even larger. Bob
Your units only take what they need no worry about too large wire.

[Wayne P.]

Put the fuse at the battery.

You can't "send" too much amperage. The units use amperage and you use a fuse that the installation instructions state.
The fuse is to protect the smallest conductors and unit in the circuit. The larger wire is to reduce voltage loss due to wire length resistance added to the power cord.

[JSU Fishing]

How do you guys feel about 14 ga. for size if I am running a separate pair for each unit? I have read that a lot of guys are running a pair of 10 ga. to a buss, then 14 to each unit from there.

[LennyB]

14 gauge wire is plenty for electronics. It is generally rated for 15 amps continuous, meaning it is good for carrying 15 amps all day long. The larger Humminbird units (15 inchers for example) have a continuous amp draw of 3.75 amps and a maximum peak of 5.9 amps. Make sure to size the fuse to protect the weakest component, which will be your electronics. Read the owners manual to verify what size the manufacturer recommends for the unit you have.

The 10 gauge to the buss and then 14 out to the unit is good. Make sure to place the fuses near the buss and size the fuse to the manufacturers recommendation for each unit.

[bobcoy]

Lenny, A fuse needs to be at the power source to protect that wire to the buss then the proper fuse size for the electronics at the buss. We are not as concerned with the ampacity of the wire as you stated the units don't draw a great amount. We are however concerned with the voltage drop. Which will increase with time in a wet environment. As long as the feeder to the electronics is a short distance of 14 is ok but 12 would be better. With the relatively short distances on a boat a little larger wire is not going to be a big cost factor. Why skimp? Bob

[riverc]

Fuse at the battery like others have said.Both my Helix 10's have 3 amp fuses and 10 ga wire no problems with voltage drops.

[LennyB]

Yes, I agree.

[LennyB]

Yes I Agree.

[Wallace]

+1

[sfw1960]

Put the fuse at the battery.

X22 ... LOL