Nuisance tripping of residual current circuit breakers: A practical case

• Residual current circuit breakers (RCCBs) are used to provide protection against indirect contacts.
• Nuisance tripping of RCCBs sometimes become a serious problem.
• Low-order harmonics with small values it is improbable that can explain the tripping of an RCCB.
• Strong perturbations in the supply voltages produce leakage currents and cause RCCBs to trip.

Residual current circuit breakers (RCCBs) are often used to provide protection against indirect contacts in a grounded electrical installation. However, there are situations where the use of RCCBs presents certain problems. In some installations, tripping may occur for no apparent reason. Furthermore, it is very laborious and difficult to find the cause of such nuisance tripping in RCCBs. This article presents a case studied by the authors in the La Fe Hospital in Valencia (Spain), where the nuisance tripping of RCCBs became a serious problem. The methodology followed to find the causes and the solutions adopted are described.