difference between over current and over load protection?

Answer Posted / harry

Overcurrent protection is protection against excessive
currents or current beyond the acceptable current rating of
equipment. It generally operates instantly. Short circuit is
a type of overcurrent. Magnetic circuit breakers, fuses and
overcurrent relays are commonly used to provide overcurrent
protection.

Overload protection is a protection against a running
overcurrent that would cause overheating of the protected
equipment. Hence, an overload is also type of overcurrent.
Overload protection typically operates on an inverse time
curve where the tripping time becomes less as the current
increases. Overload relays as well as “slow blow” fuses are
commonly used to provide overload protection.

Some devices provide both overcurrent and overload
protection. A thermal-magnetic circuit breaker has both
thermal (overload) and magnetic (overcurrent) elements. Both
elements operate as described above. Likewise the dual
element fuse has both instantaneous and inverse time
characteristics in the same fuse providing both overcurrent
and overload protection.

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