Finally installed my fuse box!

[Reducto]

I bought a Blue Sea Systems fuse box months ago on a recommendation from a thread in here but just kept putting off installing it. My wiring is a rats nest of splices and was a problem waiting to happen. It finally DID happen yesterday! I returned to my van after a night out and nothing worked in the back. The big fuse at the battery had blown. I cut a few of the more dodgy bits of wiring out, replaced the fuse, and that one blew too.

I finally installed the fuse box and have started the process of running wires from it to each powered item with its own fuse. The short is in the wire leading to my roof fan, I just need to pull down the ceiling to find the cause.

Luckily I at least had big fuses at the car and house batteries so there was no fire! I wish I had done it right in the first place with individual fuses, it would have saved me some time tracking down the short and re-wiring everything.

 

[GotSmart]

I installed one back about 9 months ago. It has saved me a lot of problems by being another safety in my system. I would recommend bypassing the wire first to see if it is the fan itself, rather than tearing everything out first.

 

[MikeRuth]

It seems when installing the roof vent/fan units that if your close on the 14 x 14 dimension they fit pretty snug and I too had pinched a wire. Same in my case, take a roof panel down and fix.

How big is the "big fuse"? I'm thinking you just got really lucky, in as much my big fuse is 150 Amps and I guarantee that the wiring leading to the fan would have burned up before the big fuse blew. In my case If I hadn't fused down for the fan I would have certainly had burned up wire. If I recall the Factory wire is about 18 gauge and in free air that can handle no more than 16 amps. No way 125 amp fuse is gonna blow.
I'm using the Max Fan vent and I have tested it to 5 amps on high, start-up has a surge of about 8 amps if it's on high but for a very short duration. So I fused it at 7.5 amps.

Mike

 

[Reducto]

The "big fuse" is 80 amps, which is higher than what my alternator can put out. The new one blew instantly so apparently my wiring can take that much pretty easily.

 

[highdesertranger]

well if you are blowing an 80 amp fuse you have a pretty significant short and not in a small wire. like mike ruth said the wire would have fried before the fuse blew. highdesertranger

 

[Wabbit]

...My wiring is a rats nest of splices and was a problem waiting to happen...

PICS!!! Lol, Before and After!!! Hope you get it figured out quickly.

 

[MikeRuth]

WOW as HighDesertRanger said you have one big short going on. I'd be freaking out looking for that fast.

To blow an 80 amp fuse and not have smoke your looking for a really large wire that has shorted or one very close to the fuse.

 

[Reducto]

The short was indeed in a pinched wire at the fan. It just took 3 years to rub enough insulation off and become a problem. I wonder if it was leeching power for a while before this? Maybe I'll have more available now? Oh well.

10 feet of #14 wire is indeed enough to trip the 80A fuse I'm using. It only needs to hold that much current for a tiny fraction of a second.