1. Breakers for protections against earth faults too small to trip an over-current device:
- Residual-current device (RCD, formerly known as a residual current circuit breaker) — detects current imbalance, but does not provide over-current protection.
- Residual current breaker with over-current protection (RCBO) — combines the functions of an RCD and an MCB in one package. In the United States and Canada, panel-mounted devices that combine ground (earth) fault detection and over-current protection are called Ground Fault Interrupter (GFI) breakers; a wall mounted outlet device or separately enclosed plug-in device providing ground fault detection and interruption only (no overload protection) is called a Ground Fault Circuit Interrupter (GFCI).
- Earth leakage circuit breaker (ELCB)—This detects earth current directly rather than detecting imbalance. They are no longer seen in new installations for various reasons
2. Autorecloser—A type of circuit breaker that closes automatically after a delay. These are used on overhead power distribution systems, to prevent short duration faults from causing sustained outages.
3. Polyswitch (polyfuse)—A small device commonly described as an automatically resetting fuse rather than a circuit breaker.
Source:
http://en.wikipedia.org/wiki/Circuit_Breaker
