Residual current devices

Residual current devices minimise the risk of a person receiving an electric shock or being electrocuted when using plug-in electrical equipment on board vessels.

The risk of injury or death increases when electrical equipment and wiring is damaged or when used in wet surroundings. 

Vessel owners and operators must ensure that RCD’s are used whenever 240-volt electrical supplies are in use. This is a part of their general safety duties under the national law.   

How residual current devices work 

RCDs are designed to immediately switch off the power supply when electricity leaks to earth at a level that is harmful to a person. 

If a power tool is plugged into a power socket protected by an RCD, the operator is unlikely to receive a fatal electric shock if the tool, cord or socket happen to get wet. 

Testing residual current devices 

Under state and territory laws, RCDs must be inspected and tested every 12 months to make sure they function as intended and the cut-off is triggering within the specified timeframe. 

They must also undergo a push-button test every three months for portable devices and every six months for fixed RCDs. 

RCDs that are fitted to isolated earthing systems require specific testing procedures. Refer to any instructions provided by the device manufacturer.

You must keep a record of testing until the device is next tested or is disposed of. 

Who can inspect and test an RCD 

Push-button testing can be done by any crew member. 

Yearly inspection and testing of RCDs must be done by a competent person such as a licensed electrician or accredited marine surveyor with accreditation in the appropriate electrical survey categories, or a person trained to use an RCD tester. 

Protecting your crew 

As the owner or operator of a domestic commercial vessel, it is your responsibility to ensure the safety of your crew. 

  1. Do a risk assessment as part of your safety management system to:
    • identify the hazards while using electrical equipment 
    • assess the likelihood and consequences of the risks
    • eliminate the risks, or if this is not possible, reduce the risk of injury (controlling the AMSA661 risks). 
  2. Implement ways to control those risks. For example:  
    • Use battery or pneumatic/hydraulic-powered tools instead of 240-volt electrical tools where possible.
    • Use RCDs on all electrical circuits used to supply electricity to portable electrical equipment.
    • Use portable electrical equipment designed for use in a marine environment. If this is not possible position equipment where they will not come into contact with water (including wave spray and deck flooding).
    • Make sure people using portable electrical equipment are trained on safe usage.
    • Wear appropriate personal protective equipment when using portable electrical equipment such as rubber boots and gloves.

Case study

A deckhand working on a fishing vessel operating in the Gulf of Carpentaria was electrocuted while operating a 240-volt portable angle grinder. The grinder, connected via an extension lead to a power socket within the vessel was not protected by an RCD. The deckhand was not wearing any personal protective equipment. 

While in use, water from a wave made contact with the angle grinder and its plug resulting in electrocution. 

The Coroner agreed with findings that if an RCD had been fitted to the power socket, the deckhand may not have died.

More information

Worksafe agencies and legislation

Last updated: 16 October 2023