On Tuesday, August 25, 2015 at 2:38:23 AM UTC-4, Surge wrote:
On Monday, 24 August 2015 20:10:07 UTC+2, Dave Nadler wrote:
PS: This might be a good time to replace your fusing with current
automotive style blade fuses - they are MUCH more reliable!

I can second that.
Thanks to the recommendations on RAS I'm rewiring my old glider and using blade fuses. Cartridge fuse holders are not very reliable especially if they are mounted on wires that are moved/bumped around a lot.
Blade fuses are cheap, reliable and can be found at any electronics store, fuel/gas station or motor spares stores.

From what I've seen in older gliders the trend appeared to be a main fuse at the battery (or batteries) and one or two main instrument fuses mounted in the instrument panel (usually of the cartridge type). I'm not sure if this was done by the manufacturer or installed later by glider owners but I think it is a very silly set up.
If there is a short circuit in one of the instruments or related circuits, you lose all your instrumentation when the main fuse in the panel blows and you're unlikely going to be able to rectify the short circuit in flight so replacing the fuse will most likely just result in more blown fuses.
The same logic applies to resettable fuses.

Rather fuse each instrument separately according to manufacturer specifications so that if an instrument or related circuit develops a short you only lose that portion of the circuit instead of everything.
I've moved all the instrument fuses (eight of them) behind the instrument panel into a fuse block holder to save panel space and remove the temptation to fiddle when my attention should be outside the cockpit.

10 or 15 Amp fuses right at the battery terminals
14 gauge wire from the batteries to the panel (bit of an overkill)
1,2,3 or 5 Amp fuses for each instrument according to manufacturer recommendations

Sorta agree..... fuses/breakers keep the wires from becoming "candles" when overloaded. Then use a smaller fuse/breaker to protect the next thing in line.
Breakers tend to be "slow blow", which usually "lets the smoke out" before tripping but help prevent/limit fires.
Fuses come in many flavors, from "dual element/motor start" (lots of short overload can go through) to "fast blow" types to save sensitive stuff.

Again, fuse/breaker MUST be equal to or lower than the ampacity of the wire carrying power, fuses/breakers can be even lower than the wire ampacity, but MUST NOT be higher than the wire rating.