Most modern consumer units will have more than one RCD or RCBO fitted therefore it is essential that there are monthly checks carried out to make sure they are functioning properly. These checks should be carried out regardless if you own a property or if you are renting the property to someone else.  

The reason that RCD’s need to be tested is because that they work through moving parts and electromagnets. These magnets are only active when there is a fault therefore it is quite common for these parts to seize up. This won’t be detected during normal operation therefore testing is the only way to rule out these types of faults. If the RCD has seized it won’t be able to operate therefore it won’t be able to protect you from harm and in the worst case it could cause a fatal electric shock.

The consumer unit itself should have a label attached to show the requirements and how often the RCD’s need tested, often by pressing the test button when the electric supply is on.  When you push the test button this should disconnect the power supply and move the switch to an off position. Moving the switch to the “on” position will re instate the power which will indicate your RCD is functioning properly.

If the RCD does not trip the circuit it means you are not protected in the case of a fault as the power is not cutting out. In this case you should contact your electrician so they can fix the problem; most often this is done by replacing the RCD.