Can you replace a 20 amp fuse with a 15 amp fuse?

Answer 1

Yes you can. It will provide better protection because it will blow quicker than a 20 amp if there is a fault in the circuit.
Not advisable. If the normal current is little more than 15 amps, then the fuse will blow. If the actual current is less than 15 amps, then it would work.

Answer 2

It is not recommended to replace a 20 amp fuse with a 15 amp fuse as it may not provide enough protection for the circuit. Using a lower amperage fuse can lead to overheating and potentially cause a fire hazard. It's best to use the correct amp fuse as specified by the manufacturer.

Answer 3

Yes, but a 20 amp fuse will not protect the #12 conductor from an overload condition like a 20 amp circuit breaker will. The fuse will only protect against high current in a circuit.

you misspoke a 20A fuse offers far more protection than any circuit breaker

small circuit breakers are sometimes rated for less than 5000A on AIC

small cartridge fuses are rated 200,000 amps

circuit breakers usually fail by welding contacts together on a short

fuses open

Type 1 circuit breakers are the worst possible choice

similar to the clixon in the coffemakers they reset after an arbitrary cool down period and have burned quite a few houses down.

now they must have two fuses in series with the clixon

these are common in battery chargers if the battery is very low they deliver all the power the circuit will supply then open for a while and try again

Type 2 circuit breakers are a bit better they will reset only after removing power

and restoring then will apply full power until they notice the overload again.

Perhaps for sump pumps you could pump out the basement

unplug the sump pump plug it back in, find the rock jammed in the impeller

plug it back in and try again.

Type 3 the only kind almost as good as a fuse must be manually reset

you may have to run up and down the stairs ten times before you notice your fondue pot has melted thru its cord and it needs to be unplugged before you can get the superbowl to come back on.

a fuse will never reset and you are more inclined to spend a couple minutes to find the problem before spending $1 for a new one