RCD protection in the form of RCD’s or RCBO’s has been commonplace in the home for well over 40 years now but as the technology we use evolves so must our safety devices. An RCD is an important piece of safety equipment which is designed to trip to protect you in the event of an electric shock.

There are various ‘Types’ of RCD’s and the most common which has been used for years in a domestic setting is the Type AC RCD and these work very well with resistive loads (Such as an immersion heater) which have very little in the way of electronics.

As time has gone on the types of electrical items we use has changed and there are larger amounts of electronics involved. An example of this change would be old filament or halogen bulbs being a resistive load and new LED light bulbs having electronic components. These electronic components ‘leak’ (see earth leakage helpsheet) DC electricity in to our home wiring which has AC electricity.
When DC voltage passes through an AC voltage RCD, it can ‘stun’ or ‘blind’ the RCD stopping it from tripping when it would normally do so which is a huge safety risk.

If your electrician is adding new wiring in to your home and they can guarantee that there will be no DC leakage then you don’t need to upgrade your RCD, but if there’s no guarantee then your RCD will need replacing for a new Type A RCD.  

Some RCD’s have a little symbol on the front which tells us which Type they are. If you’re unsure you can check yourself, below are the differences in the symbols on a Type AC and a Type A RCD.

                               Type AC RCD                                                               Type A RCD