no fusing in boat wiring runs

[WTM]

ive been seeing this a lot on diy and even "pro" installs along with unlabeled conductors, no B+ or L+ terminal protection, undersized overcurrent protection to name a few. one thing to remember fuses proctect conductors, not devices, from catastrophic failures. ifin you decide you dont need a fuse within 7" or (42" if in conduit or sleeving) of the battery on that 10ga conductor and think that a fuse at the load end will protect that conductor than you have basically created a filament wire with that conductor on the unfused length, if it gets damaged and shorts to ground, ie B- short or an aluminum hull. also stay away from cheap chinese fuses and breakers. use good fuses ore breakers like bussman, little fuse, blue sea, etc.

here is some pretty good info on boat wiring and other stuff. although the ABYC standards only really includes inboards, doesnt mean that outboards are safer and shouldnt use those rules and standards.

Fusing & Termination Voltage Drop - Marine How To

5A Fuse - 5A Load As boaters looking for optimal charging performance we need to keep in mind that the path between the charge source and battery has voltage drop. This is just a fact of life. For charge sources that

marinehowto.com

you might think that i have an LFP battery and the BMS takes care of that with short circuit protection. well, take a look at this video on a well known LFP brand. scroll to almost the end if you dont want to watch the whole video. spoiler, the short circuit test failed miserably.

 

[WTM]

also this seems to be popular for some reason, cutting out the provided barrel fuse and using a fuse block instead. that particular fuse is a device protection fuse. fusing should be cascaded beginning at the battery with a higher rated fuse to protect the whole circuit and conductor then cascaded down to the device fuse with the largest allowed fuse, again protecting the conductor.

this allows the conductor to be protected and not be turned into heating element or cutting torch while keeping voltage drop to a minimum. ive seen a bass tracker burn up because the starter circuit was not protected and burned into the plastic gas tank. contrary to popular opinion, starting circuits can be fused if the max cranking amps can be determined.

back to the included garmin barrel fuse. ifin you remove it, you run the risk of voiding your warranty:

 

[WTM]

another example. this is a pro's boat with diehard agm's. no battery boot on the B+ posts. a disaster waiting to happen. 5 bucks worth of protection.

 

[FLTENNHUNTER1]

Great info thank you!