AS/NZS 61439 dielectric testing is mandatory for AS/NZS 61439 compliance as per Annex D Section 9. There are two physical tests that must be performed on every switchboard subject to the standard, and the standard does not permit reference to previous testing, or verification by assessment. For reference see the whole standard AS 61439: 2016
We have the specialist equipment and know-how to come to your site and perform these tests.
What is AS/NZS 61439 Dielectric testing?
There are two tests specific to Annex D section 9, The first test is a HiPot test specifically to verify that the creepage distances are sufficient for the rated insulation voltage of the board without a breakdown of insulation. The second test is an impulse test to replicate the effects of transient and lightning surges on the incoming mains and ensure that the clearance distances are all able to cope with these spikes without flashing over causing a potentially catastrophic arc flashover.
The details of the testing are prescribed in AS/NZS 61439 section 10.9, and they are very specific about voltages, current capacities of the test equipment and pass / fail criteria. The tests required to comply with the standard fall well outside the capability of standard insulation testers and HiPot testers.
What is the real-world purpose of these tests?
It is not just about compliance with a mandatory standard just for the hell of it! The purpose of this clause is to minimise the possibility of arc flash events when the board is installed, and all the potential for harm and damage to equipment that these events cause.
The main causes of arc flash events are insulation failure, arcs caused by lightning or transients and human error during maintenance. These essential factory tests and certification are proof that the switchboard is able to cope with the worse situations that the network can present to them, within the specification of the assembly.
Why do these tests need to be done for every switchboard?
Every switchboard or control panel will have busbar spacings, busbar mountings and cable terminations that are unique to the electrician who has built the board, and it is feasible that there could be an issue with build quality:
- Cable lugs too close
- Installed protective devices / switches insulation not at specified level
- Busbar insulators / spacers incorrectly installed
- Stray cable strands
Upon successful completion of these AS/NZS 61439 dielectric tests, the builder can be confident that the assembly can be installed and cause no dangerous insulation failures for its lifetime, under the specified environmental conditions (Pollution class).
Will my board be damaged from executing these tests?
There will be no damage or degradation to any equipment that is rated to the correct level according to the specification of the board in terms of insulation voltage and impulse voltage withstand. Any equipment that fails during this test is out of specification and needs to be returned to the original manufacturer under warranty.
How long does the test take?
The AS/NZS 61439 dielectric test does not take long at all, but there is a lot of preparation and safety precautions that need to be undertaken as it is a potentially dangerous high voltage test. The area around the switch board will need to be cordoned off and many other specific safety measures are needed.
We are also equipped to complete ground bond testing, which is another mandatory requirement for every switchboard as per Annex D, section 5. This is a ground bond test and not a simple continuity test.
See our other blog post describing our capabilities as your partner in achieving AS/NZS 61439 compliance. AS/NZS 61439 Compliance Navigation
Contact us today to discuss your switchboard testing requirements.
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