What Causes An RCD To Trip
This web page lists possible causes of RCD trips.
When investigating a tripping RCD always look for patterns – have you just turned an appliance on? Is it raining? Does the RCD always trip at the same time each day? A pattern will give clues to the cause.
Why An RCD Trips
RCDs (Residual Current Devices) are electrical safety switches that remove the supply to an electrical circuit when the circuit is unsafe; if an RCD ‘trips’ it has tripped for a reason, the problem is rarely a faulty RCD.
Judge Electrical ‘Find & Reset An RCD + Investigate A Constantly Tripping RCD’ web page.
Possible Causes Of RCD Tripping
Faulty appliance – unplug all electrical appliances, does the RCD reset OK? If the RCD resets OK plug the appliances back in one at a time. Reset the RCD as you plug each appliance back in to find the faulty appliance.
Incorrect RCD current rating – RCDs have ‘current ratings’ similar to fuses. The current rating is the current that trips an RCD. The current rating of the RCD could be too low. Seek advice from a qualified electrician. Judge Electrical offer free advice.
Poor quality RCD – poor quality RCDs can trip when they shouldn’t. Seek advice from a qualified electrician. Judge Electrical offer free advice.
Items with motors or pumps starting – many items with motors or pumps, for instance showers and pond pumps, cause momentary electrical spikes that are big enough to trip RCDs. Seek advice from a qualified electrician. Judge Electrical offer free advice.
Older washing machines – aging washing machine heating elements can cause momentary electrical spikes that are big enough to trip RCDs.
Certain wash cycle phases – some cycles of the washing machine, for instance the spin cycle, can cause momentary electrical spikes that are big enough to trip RCDs.
Certain dishwasher cycles – some parts of the dishwasher cycle draw a lot of current, a faulty component, for instance the motor, can trip an RCD.
Overloading a washing machine – too many items in a washing machine can cause certain wash cycles, for instance the spin cycle, to trip an RCD.
Fridges and freezers cooling – the fridge or freezer cooling motor starting.
Turning a sun bed on – a sun bed uses a lot of electrical power, the surge in electrical power can trip an RCD.
Turning an heating element on after a long time of being off – moisture in heating elements can trip an RCD, for instance in a sun bed or electric fire. Try resetting the RCD a few times so that the heating element can cause the moisture to evaporate.
Pond pump faulty – pond pumps sometimes have to ‘work very hard’– for instance when they have ‘digested’ part of a plant from the pond. Check your pond pump for blockages.
Moisture in outside electrical distribution boxes – remove the supply and dry the distribution box. Check the weather seals have not perished.
Moisture in outside electrical sockets – remove the supply and dry the electrical socket. Check the weather seals have not perished.
Ice maker on a fridge – a faulty ice maker on a fridge can cause ‘nuisance’ RCD tripping.
De-frost timer on a fridge or freezer – a faulty defrost element on a fridge or freezer can cause ‘nuisance’ RCD tripping.
Central heating elements – faulty heating elements can cause an RCD to trip when they are turned on by a timer.
Water heating elements – faulty water heating elements can cause nuisance RCD trips when the thermostat tells them to heat the water.
Moisture in wiring – moisture in the electrical wiring is a common cause of RCD trips. Have you just emptied a bath? Taken a shower? Is it raining – rain can get into the electrical wiring under the floors or in the loft.