How does an RCD work?
An RCD constantly monitors the current flow of the Active and Neutral wires that supply current to a piece of equipment plugged into a power point. When running correctly the current flowing between the Active and Neutral wires is equal, but when an earth leakage is detected due to a fault in the circuit or the equipment, this imbalance is detected by the RCD which cuts power to the circuit before injury of damage can occur.
An RCD detects and disconnects in under 20 milliseconds of the leakage current, stopping the flow of electricity potentially through a person’s body to earth, most importantly, the RCD will disconnect the power supply in sufficient time than the cardiac cycle therefore greatly reducing the risk of death or serious injury as detailed below.
0-1 mA – Perception level, slight tingling, minimal reaction in most cases
1-5 mA – Slight shock felt, not painful but tingling sensations. Involuntary muscle reactions may occur
6-15mA – Painful shock, involuntary muscle contractions. Can be difficult to let go of equipment while current is flowing.
16- 40mA – Severe Pain and shock. Potential breathing difficulties above 20mA. Possibility of reversible disturbance to rhythm of the heard and cardiac arrest is possible at higher current levels.
40 -300mA – Very severe and painful shock. With potential for severe muscle contractions and nerve damage, Ventricular fibrillation (uncoordinated / uneven pumping of the heart). Heavy burns into higher current flow with electrocution and full cardiac arrest occurring with a potential of death.