Question

To which wire do you connect fuse wire in a household circuit

Answer 1

Generally the whole house is protected by a circuit panel that uses circuit breakers instead of fuses. We no longer use fuses as a our main method. However, some devices have a built-in fuse protection of that item in and of itself rather than relying on the protection of the circuit breaker. For example, if you have an electrical drill, it might have a fuse, or if you ever used a sewer snake machine, it usually has some kind of overload protection circuit. The fuse is always on the "black wire" or the "hot side". It's never on the "white wire" or the "green wire".   What kind of circuit are you looking to protect and is the circuit an inductive circuit or a circuit carrying light bulbs and other heat producing devices? The answer by Andrew Daviel is pretty detailed and thorough, as well as those of others.