How to calculate the value of a FUSE which is to be employed in a circuit by wire's resistance and load resistancei read somewhere that 8g of wire needs 50 amp fuse and 14g needs 10 amp,so my question here in second part is how does we relate wieght of wire to the amps of fusekindly proceed for a answerthnx
I suspect that by 8g and 14g, you are referring to guage (awg), the cross sectional measurement of the wire, rather than grams, the weight of the wire. The general rule is 15A for14 awg, 20A for 12 awg and so forth. Once the load of the circuit is determined (say, 8 amps continuous duty and a momentary 18 amp start up), we must also consider the total length of the wire run and the resistance of the wire over this length if the source is a considerable distance from the load. If the run is relatively short and the resistance is negligible in this example, we can calculate the fuse needed to provide the power necessary while protecting the wiring from a short circuit and possible fire hazard.
weight of a wire has nothing to do with the fuse size. After all, the same weight could describe a very long thin wire that could only handle a low current, or a short thick wire that could handle a lot more current. You can look up the wire's current capability in wire tables. Or consult your local wire codes, for house wiring. For example, AWG 14 wire should be fused for 15 amps, AWG 12 for 20 amps. If the fuse is to protect the wire, size it via the wire tables. But often the fuse is to protect electronic components, and it that case, other rules apply. .
