- Feb 12, 2009
- Reaction score
- Clovis Ca
Time delay fuses can very helpful with motors and stick welders. There rated about 3 to 5 times for 10 to 20 seconds for motors or welders to start.As far as fuses vs circuit breakers, I am firmly in the circuit-breaker-only camp.
In industry, where 3-phases are used, you never want to trip off only one phase to motors and such, and so many industries outlaw fuses except in special circumstances.
In residential use, fuses are fine, but are not renewable, and so you have to stock a supply of every size.
You may get slightly better protection with a fuse in some circumstances, but a fuse does not necessarily offer better overcurrent protection than a circuit breaker.
A circuit breaker is comprised of two components, which is an instantaneous-trip magnetic coil, and a thermal element that heats up over time to trip a breaker.
The idea is for a large short circuit, the magnetic portion of the breaker will trip it instantly.
For an overcurrent, which is not a short circuit, but rather a slight excess current above the breaker rating, the breaker is designed to not trip immediately, since it takes time for the bimetalic element to heat up and trip, so that motor staring surges or other temporary surges will not trip a breaker.
Breakers will trip at a lot lower amps.