The fuse protects the wire, not the device
Six rules that prevent fires. All boring.
Six rules that prevent fires. All boring.
Nobody posts photos of their fuse block. It's still the part that decides whether your build is safe.
Rule 1: The fuse protects the wire, not the device. Fuse sizing is based on the wire's safe current capacity. Get this backwards and you'll install a fuse too large to ever protect the cable it's on.
Rule 2: Fuse as close to the source as physically possible. Any unfused length between battery and fuse is unprotected — a short there has nothing to stop it.
Rule 3: Size wire for current AND length. Two separate problems. Current determines whether it overheats. Length determines voltage drop.
Rule 4: Interrupt rating is real. Facing a lithium bank's short-circuit current, a cheap fuse can arc across internally instead of clearing — meaning it doesn't actually stop anything.
Rule 5: Crimps, not twists. Right terminal, right crimper, pull-test every one.
Rule 6: Protect against chafe. Wire moving against metal wears through and shorts. Grommets at every pass-through.
The Power Sizer turns your real appliance loads into a full spec — battery bank, solar array, controller, inverter and roof space — then matches it to gear that actually fits the number.
Open the Power SizerFree · no ads · no signup