On 14 Sep, 11:43, wrote:
I've been doing a major re-wire of the boat we recently bought in
Belgium, it's going pretty well and much of the horror is now tidied
up (it had suffered from the typical car wiring types of bodges, wires
draped around the place, lots of ends poked into one terminal, etc.,
etc.)

I have installed a couple of consumer units to provide switching and
protection for individual circuits but there are still two 'master'
fuses between the batteries (separate leisure and starter batteries)
and the consumer units feeding all the circuits.

The existing fuses are 'bottle' fuses and I'm wondering whether to
retain them or to replace them. *I certainly want easy to replace
fuses (i.e. not needing a screwdriver or spanner) as one doesn't want
to have to find tools in an emergency. *I need something in the region
of 60 to 100 amps though. *Currently one fuse is 63 amps and the other
is 35 amps. *If I stay with the bottle fuses I want to make both 63
amps which means I need to change one of the fuse holders and getting
a replacement fuseholder may be a problem although it looks as if
Farnell have a possible DIN rail mounting holder, I'm not sure how
easy this will be to fit.

So, are there any reasonably economical alternatives with 'replace by
hand' fuses with ratings in the 60 to 100 amps region? *They want to
be reliable as well though don't need to be capable of use at high
voltages, this is a 12 volt system.

Then, in addition, I want to protect the 'heavy' stuff. *The starter
battery also feeds the starter motor (surprise!) and the bow
propellor. *Currently (no pun intended) these are wired direct to the
battery and I'm thinking some sort of protection for this wiring would
be a good thing too. *The connection to the bow propellor in
particular is long and circuitous and a fault could easily start a
nasty fire in an inaccessible place. *The wires from the batteries to
the existing bottle fuses are also unprotected (only a couple of feet
or so, but still a fault is possible).

I'm thinking that the easiest approach for this is a fuse in the
ground wire to the batteries, it's where the battery isolation
switches are already wired so adding a fuse here would be reasonably
accessible. *It looks to me as if a couple of Littelfuse 'mega fuse'
links would do here, they have screw connections but at around 500
amps I guess that's inevitable. *Are there any practical alternatives
to the 'mega fuse'?

--
Chris Green

Most fuses and switches intended for AC mains are not suitable for DC
even thought it's a lower voltage.
That's why a lot of automotive stuff gets used on boats.