07 September 2013

The RCD that automatically resets itself


NUISANCE TRIPPING is one of the most common electrical faults that Sparks has to deal with on a regular basis. Because this type of fault is intermittent it can prove extremely difficult to find unless the fault is present at the time of testing or unless it is visually apparent. Consequently, finding the cause of nuisance tripping can become a major exercise for an electrician to trace.

An RCD (aka Interruptor Diferencial) that annoyingly trips out every now and then with no apparent indication why, is not only frustrating but a major concern when leaving a property unoccupied for any length of time. I have several instances on people returning home to the stench of rotting food where the fridge freezer has defrosted due to the RCD tripping out while they were away because of a temporary fault on their electricity supply.

An RCD monitors your electricity supply 24/7, if the device spots an imbalance or leakage it disconnects the power supply to prevent the risk of electric shock. However inconvenient it may be that your electricity cuts off you should never disconnect or bypass an RCD. It is there to prevent serious electrocution, removing it could prove fatal.

There are several ways on how to approach locating this type of fault depending on the installation, all of which use the process of elimination until the fault is found. Another option is to fit an automatic resetting RCD.

An automatic resetting or restart RCD is an earth leakage protection device that is technically referred to as a “recloser”. The automatic resetting function allows reclosing of the RCD after clearance of the fault and following insulation monitoring. The benefit of insulation monitoring offers maximum continuity of supply. This also provides optimal protection and safety, achieving peace of mind. Some models are fitted with an auxiliary contact that allows an installation to be monitored remotely.

An RCD with an automatic recloser can differentiate between a temporary power fault and a permanent power fault and quickly restore power without human intervention. This helps reduce power outages and improve the reliability of the power supply.

Automatic recloser RCDs are useful for applications that require an essential power supply. They are most commonly used for commercial and industrial applications such as bank cash points, cold storage rooms, telecommunications, street lighting and illuminated traffic signs. However, they can also be useful for home applications such as fish tanks and fridge freezers, as well as for community supplies powering urbanisation lighting and TV-SAT/internet services.

Sparks recommends the RED - Multi 9 automatic recloser for earth leakage protection manufactured by Schneider Electric. Click here for the full technical specification.