A nuisance trip is an unwanted operation of a breaker, RCD or relay when nothing needed clearing. Usual causes are cumulative earth leakage from many electronic loads on one RCD, inrush on transformer or LED circuits, harmonics heating thermal elements, poorly coordinated settings and CT wiring errors. Repeated nuisance trips tempt people to raise settings or bypass protection, which is how genuine faults later go unnoticed.
That 30 mA RCD on the server room circuits keeps nuisance tripping, forty power supplies are leaking 22 mA before anything goes wrong.
Also heard as
- false trip
- spurious trip
- unwanted trip
Related terms
RCD
Residual current device: trips when the current going out on the live conductors does not all come back.
Inrush current
Large transient current drawn when a transformer, motor or capacitive load is first switched on.
Selectivity
Arranging protection so only the device nearest a fault operates and the rest of the system stays in service.
Trip
To open a circuit breaker automatically through its protection, or to order a breaker open by command.