How to check if a fuse is good/bad in a live circuit using Multimeter?

VERY SIMPLE, APPLY BOTH PROBES ACROSS FUSE,SET METER TO AC VOLT.

IF NO READING IS SHOWED, FUSE IS GOOD.

IF SHOWING 120Vac, FUSE IS OPENED.

If the circuit is Live then the fuse is good. If the circuit is dead then the fuse MAY be bad.

If you connect a voltmeter across the fuse, it will read zero volts if the fuse is good. Set the meter on a scale higher than the line voltage, as it will see line voltage if blown.

BUT this is not a guarantee, as if the fuse is open AND there is no load on the circuit, the voltmeter will see an open circuit and, depending on the type of meter, may read zero. An ordinary digital DVM will show a fluctuating voltage near zero as the meter leads pick up atmospheric noise. An analog voltmeter will read zero.

Another method is to connect the voltmeter between the load side of the fuse and neutral or ground. It will read line voltage if the fuse is good and close to zero if the fuse is bad. This method avoids the possible false reading of the first method.

Simple answer: A good fuse will have no Voltage drop

when it's circuit is loaded.