Some types of electrical and electromagnetic interference caused by the network or its environment may affect the operation of earth leakage protection devices and causes their tripping without existence of fault ,which is known by Nuisance tripping (tripping in a non-dangerous situation).

This type of tripping is caused by :
1-A transient or continuous high-frequency voltage that is superimposed on the normal network voltage (50 Hz).
2-High-frequency harmonics
3-Low-frequency continuous leakage currents
4-Switching capacitive or inductive components
5-Common mode voltage surges

Type SI RCDs have been designed to avoid nuisance tripping or non-tripping in case of polluted network, lightning effect, high frequency currents, RF waves, etc.

Released for:Schneider Electric South Africa