Why No Main Fuse Between Batteries and Battery Switch?


I have a 2007 Jeanneau Sun Odyssey 39i. I noticed that there is no fuse between the house batteries and the house battery switch (they are connected by about 4 feet of 0 gauge wire) and I've seen otherJeanneaus setup the same way, presumably they come from the factory this way. Independent circuits are fused downstream of the battery switch. I've seen your videos suggesting that there should be a master fuse near the battery. Why is it that Jeanneau doesn't think there needs to be, and how important is it for me to add one?  The situation is the same for the startery battery: no fuse between the starter battery and the starter battery switch, nor between the starter battery switch and the starter (though I have heard that the starter motor circuit need not be fused). Thanks, Erik


Hi Erik, good observation, assuming your house battery distribution will NOT start the engine under any circumstances, then yes you should have a fuse in between the battery and the positive distribution. The fuse should be located at or near the battery and is there to protect the wire between the battery and the positive distribution.  The starter motor is a different issue, and starter circuit do NOT need to be fused. Notwithstanding, since the started circuit is NOT fused, you’ll want to make the starter wire circuit is protected against chafe and accidently shorts. Also, make sure you have a protective boot cover over top of the starter solenoid wire connection at the engine.  - Jeff