Nuisance tripping of residual current circuit breakers in circuits supplying electronic loads

• RCCBs are used to provide protection against indirect contacts.
• Nuisance tripping of RCCBs often occur in circuits that feed electronic loads.
• Phase currents suffer high peak values that may also trip the circuit breaker.
• Voltage disturbances in circuits feeding electronic loads 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 circuits that feed electronic loads RCCBs often cause nuisance tripping. This article discusses the reasons why RCCBs trip in this type of circuit based on a previous case studied by the authors at ‘La Fe’ hospital in Valencia (Spain) and several tests performed in a power flexible laboratory. A theoretical circuit used to explain the phenomena is also presented.