Residual Current Devices (RCDs), commonly referred to as safety switches, are critical electrical safety devices used across Australia to protect people from electric shock and reduce the risk of electrical fires. 

An RCD is a safety device designed to monitor the flow of electrical current through a circuit. It continuously compares the current in the active and neutral conductors. If an imbalance is detected—indicating leakage to earth—it automatically disconnects the power supply within milliseconds. This rapid disconnection significantly reduces the severity of electric shock and can prevent fatal incidents.

RCD testing is governed primarily by the WHS Regulations 2012 (r165) and guidance on frequency is provided by AS/NZS 3760:2022 In-service safety inspection and testing of electrical equipment.

Key requirements include:

• Regular testing of RCDs in workplaces and certain residential environments
• Maintaining records of testing and results
• Ensuring testing is conducted by a competent person for formal tests 

Typical testing intervals include:

• Push button testing: every 6 months (or more frequently for portable devices)
• Trip time testing: annually or every 2 years depending on the environment 

What is it?

Push button testing involves pressing the “T” or “Test” button located on the front of the RCD.

What does it check?

• Confirms the mechanical operation of the device
• Simulates a small leakage current internally
• Ensures the RCD switches off (trips) when activated 

However, it is important to understand that:

• It does not verify the speed of operation
• It does not test the full electronic sensing capability 

As a result, while push button testing is essential, it is considered a basic functional check only. 

Who can perform it?

• Can be completed by a competent person or user
• No specialised equipment is required 

Testing frequency

• Fixed RCDs: typically every 6 months
• Portable RCDs: before use or at more frequent intervals depending on the environment 

What is it?

Trip time testing is a formal electrical test performed using specialised RCD testing equipment. It measures the actual time (in milliseconds) it takes for the RCD to disconnect power under fault conditions.

What does it check?

• Confirms the RCD trips within required time limits
• Verifies compliance with Australian Standards
• Ensures the device will operate quickly enough to prevent serious injury 

Trip time is critical because the duration of electric shock directly impacts injury severity. 

Maximum trip times (AS/NZS 3760)

• Type I (10 mA): ≤ 40 milliseconds
• Type II (30 mA): ≤ 300 milliseconds 

If an RCD exceeds these limits, it is considered non-compliant and must be replaced or repaired.

Who can perform it?

• Must be conducted by a licensed electrician or competent tester
• Requires calibrated testing equipment 

Testing frequency

• Typically annually in most workplaces
• May vary depending on risk level and environment 

Push button testing and trip time testing serve different but complementary purposes:

An RCD may pass a push button test but fail a trip time test, meaning it operates but not quickly enough to provide adequate protection.

Failure to properly test RCDs can result in:

• Increased risk of serious injury or fatality
• Breaches of WHS legislation
• Insurance implications and potential liability

Regular testing ensures:

• Ongoing compliance with Australian Standards
• Early detection of faulty devices
• A safer working and living environment 

Further information can be found in:

Examples of RCD Test record forms: