Safety Switches (Also known as RCD or Earth Leakage Circuit Breaker)
– Why do you need them and how do they work?
In NSW Safety Switches are mandatory in all new buildings and must be added if extensions or alterations are made to an existing building.
In QLD and VIC it is mandatory for all rental properties to have Safety Switches installed and NSW should be following suit.
If an Electrician works on, or adds a Power or Light circuit he must also ensure it is now protected with a Safety Switch.
Safety Switches must be installed by an Electrician, also there are other things to consider when doing this:
- Safety Switches will not be effective if the Earthing System of the building is not correct
– all metal items like reinforcing steel in concrete, metal frames, water pipes, gas pipes etc must be bonded with an earth cable.
- There must be an Earth Stake installed as close to the switchboard as possible and in an area where the soil remains moist.
- There must be an earth cable installed to all lighting and power outlets/switches/fittings.
- There is a maximum number of circuits that can be protected by one safety switch.
- More commonly these days combo breakers are available and allow each circuit to have its own safety switch and circuit breaker in the one unit.
- Fixed Appliances such as Stoves, Hot Water, and Air Conditioning are not required to have a Safety Switch, in some cases they will have one installed anyhow.
How do they work?
A Safety Switch detects any variation between the Active and Neutral Conductors of the circuit it protects.
The safety Switch will disconnect the power within 30 Milliseconds if a variation is detected.
The variation means that the current is now flowing to Earth, hence why the Earthing System must be functioning properly and installed to Australian Standards.
Here are a few examples of the reasons to have them:
- Standing in the bathroom with a hairdryer and the lead becomes loose from being wound and unwound, the active wire touches your hand.
- A child inserts a metal object into a power point and is sitting on the floor.
- A pet chews through a power cable, power board or extension cable.
In all of these scenarios if there was no Safety Switch installed the outcome would not be good.
If 240V is to pass through the body it can cause irregular heart beat, heart attacks, also there would be burns &/or loss of limbs &/or loss of life.
If you would like more information on Safety Switches AKA RCDs please check out wikipedia: http://en.wikipedia.org/wiki/Residual-current_device
If you require a Safety Switch installed please do not hesitate to contact us here at JBTECH – Electrical & Technology.