2.2.2 Residual current devices
Residual current circuit breaker and device for the protection of individuals (earth fault)
Which protection to choose? => Selection guide
What is the difference between a Residual Current-circuit breaker and an earth-fault breaker?
Earth-fault breakers ensure the protection of individuals in the event of an electric shock, and only this protection. Residual current-circuit breakers protect individuals but also electrical equipment against overvoltage (accumulation of earth leakage protection, magnetic and thermal protection).
What is the purpose of a residual current-circuit breaker?
The RCCB is a compulsory part of your electric panel according to the standard NF C 15-100. It enables to cut the supply of an electrical installation in the event of a current overload, short-circuit or leakage current.
What is the purpose of a residual current device?
We distinguish the residual current-circuit breaker from the thermal magnetic circuit breaker. This one protects the whole installation against short-circuits (magnetic protection) and overloads (thermal protection).
Residual current devices calculate an algebraic difference between the different phases (single-phase or three-phase). It this sum does not equal 0 as it should, this means that the difference goes “to the ground” or somewhere else, and eventually to a human body! Then, the circuit breaker or residual current device will detect this current leakage and trip.
The types of differential protections: A or AC?
There are 3 classes of circuit breakers:
- Differential protections type AC: protect installations against overloads caused by AC (standard circuits such as outlets, lighting).
- Differential protections type A: protect installations against overloads caused by AC or DC (devices consuming a lot of energy)
- Differential protections type F (formerly HPI): protect circuits requiring a continuity, which do not accept power cuts (freezers for example)
To protect your circuit, several devices can be put in place on your electrical panel: isolating switch,thermal magnetic circuit breaker, thermal relay and motor protection.
Examples of circuit breakers’ sizes
The size corresponds to the maximum threshold to which the circuit breaker trip to turn off the circuit. It is in amperes. Thus, it is necessary to choose the size according to the needs of your devices. Examples:
- Lighting: 10 - 16 A
- Outlet: 16 – 20 A
- Washing machine: 20 A
- Cooking hob: 32 A
We offer circuit breakers up to 32 amperes and residual current circuit breakers up to 63 amperes for installations necessitating a higher breaking capacity, such as industrial applications.