9-11 May 2023
ICC Sydney

Navigating RCD Testing Requirements and AS/NZS 3760:2010

Let's talk about RCDs for a moment, how does a residual current device (RCD) work? Hear from 2022 TFX exhibitor Rapid Test Systems as they give you the run down on all things RCD.

An RCD is a lifesaving electrical safety device that can be installed in your switchboard or integrated into a power point or portable for use in various locations.

RCD’s can sometimes be called Safety Switches or ELCB’s (Earth Leakage Circuit Breakers). They are designed to detect any imbalance in the current flowing through the circuit.  They quickly switch the power off should an imbalance be detected which may be associated with electric shock or electrocution.

Why does an RCD need testing?

Research shows that your RCD is more likely to protect you if it is regularly activated/tested.

Of the RCDs tested in the study, the RCDs that were exposed over time to fine particles of dust and moisture (a typical mine site environment), 7.1% of them failed to protect the owner as the moving component seized causing them to move more slowly than intended.

However, only 2.8% of the RCDs that were regularly tested in the same environment failed testing. This indicates that a regularly activated/tested RCD is certainly more likely to be effective at protecting you from serious injury or death in an electrical incident.

In the same way that insurance is only useful if you have paid the premium, you can only rely on an RCD to operate in the event of an incident if you know it’s working.  Hence, regular testing is essential.

Regular Testing Requirements

Australia’s model WHS regulations (as implemented in QLD, NSW, ACT, SA, NT and TAS) state RCD’s must be installed to protect circuits powering items located in a hostile operating environment.   These installed RCDs must then be inspected and tested regularly by a Competent Person and a record is required to be maintained of the testing.   Similar regulations are also applicable in WA and VIC who are yet to implement the model WHS regulations.

Are there specific RCD testing frequencies?

AS/NZS 3760:2010 is the standard that specifies the testing protocols to be implemented by Electricians/Competent Persons, and the retesting frequencies for both Fixed and Portable RCDs.

AS/NZS 3760:2010 makes retesting recommendations based on the hostility of the environment the RCD protecting.

RCD testing and inspection table

What tests need to be completed?

Each facility will have done their own risk assessment, with some requiring specific tests to be conducted to ensure the ongoing electrical safety of all staff, contractors, and visitors.   Additionally, based on your facility type, there may be additional standards to consider. This information below relates to the requirements detailed in Appendix H, 3.1 of AS/NZS 3760:2010.

Single-phase RCDs

A current, equal to the rated tripping current, shall be ‘suddenly’ applied between active and protective earth and the operating time measured

Single Phase RCD Required Test: 30mA RCD

  • Suddenly applied leakage 30mA
    • Leakage 30mA
    • Tripping within 300ms
    • Either 0° & 180°
  • Suddenly applied leakage 10mA
    • Leakage 10mA
    • Tripping within 40ms
      • Random on the sin wave

Three-phase RCD’s

Tests on 3 or 4 pole RCD’s that are used on a three-phase supply shall be undertaken individually on each phase in turn.

Tests not required under AS/NZS 3760:2010 H1.1:

  • Slowly rising current (Ramp test)
  • Half Trip
  • Both 0° & 180°
  • Earth loop impedance
    • Required in AS/NZS 3000 (New installations)
    • Required if altering the circuit in any way

What are the RCD testing apparatus requirements?

The equipment required to carry out the RCD tests should be subject to routine verification at regular intervals to ensure it is working correctly and its accuracy is maintained.

The RCD tester shall be capable of applying a rated tripping current ± 5% and measure time with an accuracy dependent on the nominal tripping time as detailed in Table H1 of AS/NZS 3760:2010:

Tripping time Accuracy
40ms ± 2ms
300ms ± 8ms

 

From experience, we know that some facilities are testing to AS/NZS 3760:2010, and others are testing way beyond those requirements.  We also know record keeping is a huge challenge for some facilities, and for others they have detailed processes in place.

The minimum RCD testing standard we should all be working towards is AS/NZS 3760:2010 to ensure that when the RCD is needed to operate, it has been adequately tested and exercised, so that the RCD trips in the required time thus giving a person the best opportunity to survive an electric shock.

For further information on your RCD testing requirements, and how Rapid Test Systems can work with you to simplify your RCD testing, please call National Sales Manager, Wayne Peters on 1300 78 1300 or visit www.rapidtestsystems.com.au

Rapid Test Systems will not only be exhibiting at TFX on 10 – 12 May at Stand A29, but are the sponsor of our Smart Buildings Theatre. Ensure you meet the team in-person and see their products in action at the show and register online for free entry for TFX here.
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