Testing portable RCDs in New Zealand (residual current devices), commonly known as portable safety switches, involves more than simply pressing the test button. You need to check that the RCD operates correctly, measure its trip time and carry out the required electrical safety tests.
In the video below, we demonstrate RCD operating tests using a Seaward PAC3760 DL, including the manual push-button test and trip-time testing at 0° and 180°.
RCD testing may include:
- Manual push-button testing
- Leakage current testing, where applicable
- RCD trip-time testing
Start With a Visual Inspection
As with any electrical equipment, and according to New Zealand Standards, testing should begin with a Visual Inspection.
Look for damage or deterioration, such as cuts, cracks, exposed conductors, loose components and signs of overheating. Check the plug, cord, casing and protective cover for any visible defects.
Perform the Push-Button Test
First, connect the portable RCD to a suitable mains power supply, following the manufacturer's instructions.
Press the TEST button. The RCD should trip as intended when the button is pressed. If it does not operate correctly, do not pass it for use.
Reset the RCD before continuing with any further tests, following the manufacturer's instructions.
Test the RCD Trip Time
The next step is to measure the RCD's trip time. In this demonstration, we perform two tests: one at 0° and one at 180°.
These tests measure how quickly the RCD disconnects the power, with the result displayed in milliseconds (ms). Select the appropriate RCD test setting for the device being tested.
For a 30 mA RCD, the applicable trip-time limits depend on the relevant standard and the type of device. Always verify the required limits before determining whether the RCD passes or fails.
The RCD will trip during each test and must be reset before the next test is performed.
If the portable RCD has multiple socket outlets, test each outlet as required by the applicable procedure. Record the results and follow the relevant requirements for documenting the test outcome.
Leakage Current Testing
Depending on the device and applicable testing requirements, leakage current testing may also be necessary.
This test measures leakage current under the specified test conditions and helps identify potential electrical safety issues. The test setup and procedure will depend on the equipment being tested and the portable appliance tester being used.
Always follow the tester manufacturer's instructions and the applicable testing standard.
What Happens If a Portable RCD Fails?
If a portable RCD fails its visual inspection, push-button test, trip-time test or any other required safety check, it should not be returned to normal use.
Clearly identify the equipment as faulty and remove it from service until it has been appropriately repaired, replaced or otherwise dealt with by a suitably qualified person.
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