Residual current devices
A residual current device, or safety switch, protects you from the most frequent cause of electrocution - a shock from electricity passing through the body to the earth. It can also provide some protection against electrical fires.
RCDs are electrical safety devices designed to immediately switch off the supply of electricity when electricity leaking to earth is detected at harmful levels. They offer high levels of personal protection from electric shock.
Workplace injuries and fatalities can be prevented by the use of properly installed and maintained residual current devices.
The managing electrical risks at the workplace code of practice has more information about the advantages and disadvantages of different kinds of non portable and portable RCDs.
You may need to seek technical advice from a competent person about the kinds of RCDs that are right for your workplace.
When RCDs must be provided for use in workplaces
RCD requirements only apply in relation to workplaces where electrical equipment supplied with electricity through a socket outlet (plug-in electrical equipment) is used or may be used in certain higher risk workplaces. These are workplaces with operating conditions where:
- the normal use of electrical equipment exposes the equipment to operating conditions that are likely to result in damage to the equipment or a reduction in its expected life span, including conditions that involve exposure to moisture, heat, vibration, mechanical damage, corrosive chemicals or dust
- electrical equipment is moved between different locations in circumstances where damage to the equipment or to a flexible electricity supply cord is reasonably likely
- electrical equipment is frequently moved during its normal use
- electrical equipment forms part of, or is used in connection with, an amusement device.
Common examples of electrical equipment requiring an RCD include:
- hand-held electrical equipment, for example drills, saws, hair dryers, curling wands and electric knives
- electrical equipment that is moved while in operation, including jackhammers, electric lawn mowers, floor polishers and extension cords
- electrical equipment that is moved between jobs in ways that could result in damage to the equipment, for example electric welders, electric cement mixers, portable bench saws and extension cords.
Additional RCD requirements may be included in AS/NZS 3000:2007, local building and electrical safety laws.
Testing of residual current devices
If you are a person with management of a workplace, you must make sure that RCDs used at work are tested regularly by a competent person to make sure they are working effectively.
A record of testing (other than push button testing) must be kept until the device is next tested or disposed of.
The managing electrical risks at the workplace code of practice provides more information about electrical work and risk controls.