P323 Main Fuse

[selene]

Hoping somebody can help...

Upgrading electrics in preparation for LiPO4, and better switching than 1-2-both. In my way is the main DC fuse. It has a big plastic cover over it - unfortunately wedged behind the water heater, so cannot be accessed/removed nondestructively. I therefore cannot see the original fuse rating (50,000 amps AC does not help!).

Does anybody have an idea of the correct fuse size for DC Main? I am assuming it is equivalent to a Class T fuse, and therefore needed in addition to the standard BlueSea 30A breaker.

[Last Resort]

on my 1990 31-2, mine was the same "shot gun shell" looking fuse, but only a 40A.  When I found it  (a screw had come loose and was shorting out the connection to my panel), I quickly replaced it with a newer 40A 2 prong push in fuse, like we use everywhere now, but it was MUCH bigger in actual size from an auto fuse.  I just took the 2 wires of the existing holder and joined them with the new 2 prong spade holder (just hanging freely, no mounting at all) and just plugged the new fuse in.  It was a 10 minute job for me as the fuse is located under my aft cabin with my batteries. Maybe you can remove/cut the 2 red wires off and move them to a more workable area. If I was going to do mine today though, I'd use this fuse holder and mount it and not have to join any wires: 

https://www.amazon.com/SCOSCHE-PMFHIKF-Maxi-Fuse-Holder/dp/B072JHSW5J?th=1

I have also switched over to LiP04 batteries and no issues.  Good Luck!!