Residual current devices (RCDs), commonly referred to as ‘safety switches’, are electrical safety devices designed to immediately switch off the supply of electricity when electricity leaking to earth is detected at harmful levels. RCDs offer high levels of personal protection from electric shock.
Workplace fatalities can be prevented by the use of properly installed and maintained RCDs.
Requirements for residual current devices
From 1 January 2013, new requirements for residual current devices (RCDs) will apply to workplaces where ‘plug in’ electrical equipment (electrical equipment supplied with electricity through a socket outlet) is used in the following operating environments:
- electrical equipment is exposed 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 with, an amusement device.
If electricity is supplied through a socket outlet that does not exceed 20 amps, then the RCD must have a tripping current that does not exceed 30 milliamps. This does not apply if the supply of electricity to the electrical equipment:
- does not exceed 50 volts alternating current
- is direct current
- is provided through an isolating transformer that provides at least an equivalent level of protection
- is provided from a non earthed socket outlet supplied by an isolated winding portable generator that provides at least an equivalent level of protection.
Information about the advantages and disadvantages of different kinds of non portable and portable RCDs are described in Appendix B in the draft code of practice Managing electrical risks at the workplace.
You may need to seek technical advice from a competent person about the kinds of RCDs that are appropriate for your workplace.
Testing of residual current devices
The person with management or control of a workplace must ensure that RCDs used at a workplace are tested regularly by a competent person to ensure the devices are working effectively. A record of testing (other than daily testing) must be kept until the device is next tested or disposed of.
The draft code of practice Managing electrical risks at the workplace provides more information about electrical work and risk controls.
Call 13 10 50 for more information about residual current devices.