What does an RCD do?
An RCD is a sensitive safety device that switches off electricity automatically if there is a fault.
It is designed to protect against the risks of electrocution and fire caused by earth faults. For example, if you cut through the cable when mowing the lawn and accidentally touched the exposed live wires or a faulty appliance overheats causing electric current to flow to earth.
How does it work?
An RCD constantly monitors the electric current flowing through one or more circuits it is used to protect. If it detects electricity flowing down an unintended path, such as through a person who has touched a live part, the RCD will switch the circuit off very quickly, significantly reducing the risk of death or serious injury.
Types of RCD protection.
Fixed RCDs or RCBOs - These are installed in the consumer unit (fusebox) and provide protection to individual or groups of circuits. A fixed RRCD or RCBO provides the highest level of protection as it protects all the wiring and outlers on a circuit, and any connected appliances.
RCDs protect a group of circuits usually on a split load fuseboard, whereas an RCBO device individually protects each circuit. An RCBO can be a lot more user friendly than an RCD.
Socket-Outlet RCDs - These are special socket-outlets with an RCD built into them which can be used in place of a standard socket-outlet. This type of RCD provides protection only to the person in contact with equipment, including its lead, plugged into the special socket-outlet. This are usually used if the fuseboard does not have RCD protection but the customer wants new equiptment that is required to be protected by RCD.
How do I check whether I already have fixed RCD protection?
To check if you have fixed RCD protection, go to your consumer unit and have a look to see if there is a device with a pushbutton marked ‘T’ or ‘Test’. This ‘test’ button is part of an RCD. If an RCD is fitted, there should also be a label on or near the consumer unit stating ‘test every 6 months’. This test can be carried out by anybody and just requires somebody to press the test button. If the RCD is functioning correctly once pushed the RCD should trip and cut power to the protected circuits. If the RCD does not trip when pressed you should contact a qualified electrician to look into this and possibly replace it.
Type A & Type AC RCD Devices.
Type AC devices can detect and respond to AC sinusoidal wave current only. Type A RCDs are used for alternating sinusoidal residual current and for residual pulsating direct current up to 6 mA. Regulations now state that all RCD devices should be A Type, so when carrying out changes to an existing circuit or installing a new circuit, you may be required to replace your current RCD.
Post Written by Perry McGowan @ VoltsCoventry
Comentários