SWITCHBOARDS
AND THE IMPLEMENTATION OF AS/NZS 61439 IN MAY 2021, THE NEW AS/NZS 61439 SERIES OF STANDARDS BECAME THE ONLY ACCEPTABLE STANDARD FOR SWITCHBOARD SPECIFICATION. TO SUPPORT MEMBERS WITH ITS IMPLEMENTATION, NECA RECENTLY RAN A WEBINAR, WHICH INCLUDED A DETAILED Q&A DISCUSSION. HERE ARE SOME OF THE KEY QUESTIONS OUR PANEL ADDRESSED. Do the new requirements apply to all switchboards or is there a minimum current limit?
If you add a Circuit Breaker (CB) to an existing switchboard, how can it be verified?
AS/NZS 61439 compliance is mandated in Amendment 2 for assemblies rated greater than 10kA and above, or for assemblies having more than 125A of connected load per phase. This applies regardless of whether or not AS/NZS 61439 is specified by the client/consultant.
Verification of the alteration includes the following:
If a tender was submitted prior to May 2021, can the switchboard still be manufactured to AS/NZS 3439?
No. The new standard applies to switchboards that are being energised from May 2021 onwards, regardless of the tender date. This may vary in certain jurisdictions.
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Is the new CB installed as per the original manufacturer’s instructions, using verified means (busbars, support, size of enclosure etc). This is expected to require consultation with the switchboard builder. Will the new load corresponding to the additional breaker overload the existing busbars? This can be verified by understanding the existing maximum demand on the switchboard section busbars, and seeing if the proposed additional load will exceed the rating of these busbars (as documented by the switchboard builder).
Will the additional load overload the main incoming breaker and/ or distribution breakers? As per the previous step, the existing load is required, and it must be verified that the additional load does not exceed the maximum rating of the supply breaker and/ or distribution breakers feeding the additional load (as documented by the switchboard builder).
What about repairs to existing switchboards? If it’s an alteration, for example adding additional circuits or a new breaker, then it needs to be certified to AS/NZS 61439. The previous question addresses the verification process. If it’s a repair, then it is not required to comply with AS/NZS 61439.
June 2021