MythBusters: AS/NZS 61439 edition
Many statements and claims have been made with regard to AS/NZ S61439, the new switchboard standard. Some true, others partly so but a few perhaps misleading. Peter Vandenheuvel gives us a helicopter view.
It’s official! Yes. As this goes to print, the switchboard industry in particular – but also the electrotechnology industry as a whole in a smaller but still important way – will be fine-tuning their practices.
Standards Australia, via Committee EL001, will issue Amendment Two to AS/NZS 3000:2018 (The Wiring Rules) which (in part), will mandate all new switchboards comply with AS/NZS 61439 Low voltage switchgear and control gear assemblies.
Mind you, it is not surprise for most; having already been anticipated when first introduced five years ago in parallel with the ‘to be superseded’ AS/NZS 3439.
Well, AS/NZS 3439 is almost 30 years old and although it served the industry very well, the change offered the opportunity to further align us with IEC Standards. This should see the electrotechnology industry benefit in using the experience from a world-wide industry base. Also, there is now a potential of more access to overseas opportunities for Australian industries – but increased sales from overseas manufacturers into Australia may also result.
In addition, there is a belief by many that as the only Australian Standard for switchboards, it will ‘lift the industries game’. Will it make the large number of highly respected professional switchboard manufacturers delivering world-class high-performance switchboards to satisfied customers be even better? I’m not sure! But it may spur on some of the lesser ‘could do better’ performers.
Is it the end of the world?
Depending on who you ask, some see it (and the apparent need for more testing) as the doom for ‘assembly manufacturers’ – previously known as ‘switchboard builders’ – whereas others will just shrug their shoulders and say it is “business as usual”.
Certainly, the initial rumours about companies needing to either spend megabucks testing or otherwise close up shop forever have so far not materialised. But that’s not to say for many – especially those that may have gotten by so far ‘on a wing and a prayer’ – that undertaking some extra testing has proven to their benefit. However, for those already with considerable test experience, very little has had to change.
How does it compare with AS/NZS 3439?
There is a difference. But it is mainly in its layout, technically not a lot has changed. Why? Because the best-practice switchboard design principles that guided AS/NZS 3439, its predecessor AS 1136 and (for us ‘seniors’ old enough to remember) BS 4070 before that were all technically sound.
After all, the laws of physics concerning Volts, Amps, Watts-loss, heat dissipation, mechanical stresses and magnetic forces were built-in at the big bang and still behave exactly now as then. So, any test – even from before 1970 – is still valid for the same application now; and will continue to be so ad-infinitum in future.
The most stand-out changes?
About the only material changes – aside from the layout which I can only rate about ‘one out of ten’ – are;- the omission of the term ‘partially type tested assemblies’ (PTTAs) but not the concept; the manufacturer now being responsible for the method of verification (aka proving it meets the standard); and the inclusion of two additional and much more detailed (and now varied) temperature-rise test procedures.
The verification of past PTTA-type non-tested parts of assemblies may be somewhat more limited but is still built-in. The additional temperature-rise test procedures are, to quote the Standard, to; ‘avoid unnecessary testing and provide guidance on selecting groups of comparable functional units, apply design rules and assign ratings’’ presumably for what are generally known as ‘modular type’ switchboard systems.
Can specifiers still have ‘a bob each way’?
Performance or prescriptive; this will definitely be more of a challenge because most switchboard specifications include specific prescriptive requirements. It is part of our specifier DNA of ‘putting their own stamp in it’.
Reading the fine print, especially dealing with ‘critical variants’ (key functional units)’ even the adding of a relay or a change in internal layout is noted as possibly requiring further verification. That could result in the specifier’s expectation for further compliance tests being undertaken.
Consequently, with prohibitive testing costs and resultant time-delays, designs will become more cookie-cutter or ‘system-based’. Accordingly, the expectation by some specifiers for every design to be ‘the same but different’ may have to result in a paradigm shift as further testing will not be welcomed by the manufacturer and any last-minute changes will also be more difficult to accommodate.
So the days of getting a ‘bespoke’ design may be drawing to a close when key decision makers involved with projects – the developers, builders and electrical contractors – may have to settle for what’s on offer and may have to evaluate more on what they are getting and less on the lowest price.
Will it grow ‘Part 1’ solutions?
One certainty; It will not reduce them. AS/NZS 3000 Part 2 will require every switchboard to (“shall”) comply with AS/NZS 61439. Any Australian or overseas purpose-manufactured assemblies for whatever reason not verified to it – but otherwise complying with the fundamental requirements of AS/NZS 3000 – will have to be accepted as a ‘Part 1 solution’. This would include for defence and other from offshore sources, as well as for specifically purposed or local specialist installations.
This may create another problem. Because of the complexity in understanding AS/NZS 61439 there will likely be strong (but rightful) refusal by manufacturers to provide their confidential manufacturing and testing intellectual property for fear of it falling into competitor hands.
As only few within the industry will actually have skills to assess compliance, it would likely fall outside the expertise of many engineers and nearly all contractors and inspectors. This will also create its own problems.
This is because all the individuals signing off electrical certificates of compliance or otherwise approving the installation would be very wise to add a disclaimer with regard to the switchboards, in case a later identified shortcoming led to negligence claims in the courts. The well-worn lawyers ‘catch all’ term for a person to “have known or should have known” when calling out poor practices may be one they could become very familiar with.
Also, there may be reluctance in some jurisdictions to accepting ‘Part 1 solutions’ thus adding a further difficulty getting Part 1 solution sign-offs.
Agreement between user and manufacturer
As with the previous Standard, the agreement between manufacturers and users remains, but it will place more responsibility on engineers, contractors and specifiers to provide the information.
This is probably one of the most helpful tables for the manufacturer in both the previous and new standards. But unfortunately, it was also the least used due to final switchboard designs often not being defined until much after the price is locked in.
However, there is now help for the switchboard builder, because – if declared by the assembly manufacturer at the outset – it can take the place of a user–manufacturer agreement. So do not underestimate its value if used correctly.
Albeit there is one warning; unless switchboard buyers – the contractors, engineers and users – become more involved in detailing the switchboard at an early stage it is very likely to go pear-shaped. And the penalty for getting it wrong may include pulling out and replacing a non-complying switchboard after it is paid for and the installation is in use, not a very attractive option!
Will the contractor or user get a test certificate?
Unlikely! Certainly not anything meaningful or one page. And there are multiple reasons; it is the manufacturer’s confidential and sensitive intellectual property; much of the test reporting is in the form of multi-page reports that must be read in their entirety; the specific tests falling under a number of different clauses being reported separately; it not being meaningful to others unless the actual switchboard(s) are identical to the one tested; many assemblers relying on parts of it being verified by different current or past testing data, being just some.
And if I may offer a perspective as a past switchboard manufacturer, it would of very great concern to have this valuable and highly confidential intellectual property circulating within the industry where it may fall into competitor hands.
In addition, with the likely closing of the Lane Cove testing facility later this year, there is likely to be only one test facility in Australia so the available testing capacity and maximum achievable testing values will be reduced.
Given that the manufacturer is the sole verifier of their assemblies, about the best that can be hoped for is a manufacturers’ verification statement. Also, for compliance concerns to be resolved by audit via the contractor or user or where there are confidentiality concerns, by a third-party independent expert.
Is test information validity time-sensitive?
No. This would be totally against the intent of the current standard where in the preface on page two, (here paraphrased) states; “where tests made to IEC 60439, IEC 61439 or AS/NZS 3439 and these tests fulfil the requirements of the relevant parts of AS/NZS 61439 the verification need not be repeated”.
Further, as the last paragraph in the preface of AS/NZS 3439 on page ii notes “all type test approvals gained in accordance with AS 1136 and AS 3439 still remain valid”. So, all previously undertaken test fulfilling the requirements of AS/NZS 61439 remain valid regardless of when they were done. There is no use-by date.
And this is only right! As mentioned earlier, the physics related to switchboard performance has not changed since the creation of the universe. So, it is only fair those industry-leading professional manufacturers who spent substantial testing-dollars since the 1970s continue to reap the benefits of their investments. In fact, it would be an insult to the entire industry if there were a prejudice against earlier testing.
Is a megabucks testing budget needed?
No, not if you spend wisely! There will be great rewards in having a well thought-through compliance implementation plan rather than a knee jerk reaction. First, look at the testing already done to assess its relevance and then carefully design a test strategy that will fill the gaps to give you the best bang for your bucks.
Recognise also, for your own credibility and future success, that having little or no test history, or no test support from a system support provider, or using test reports or certificates different to what you are proposing to manufacture will soon catch you out, and you could be that manufacturer that is pulling out a paid-for in-service switchboard not up to par.
What verification issues are important?
Ultimately, all in clause 10 ‘Design Verification’. But there are some more critical than others. If asked to name the top three most critical it would to be 10.10.9, dielectric properties, 10.10.11 short circuit strength and 10.10.10 temperature rise, and in that order. Why? A brief summary follows.
Dielectric properties: first on the list as it ensures no parts become live unintentionally and no flashovers or arcing faults starting fires are created as the key intent is to protect all near or working on the switchboard from electric shock and minimise fire risk.
Short circuit strength: this not only prevents a switchboard, or parts thereon, from failure during short-circuit faults, but also (and equally as important) confirms the switchgear installed within it does not explode or flash over during its operation, preventing the destruction of the switchgear, it is becoming unfit for purpose or doors and covers from being dislodged and becoming projectiles.
Temperature rise: not exceeding allowable operating limits. It prevents; devices and equipment from overheating failure; premature tripping; connections becoming loose; connection burnouts, arcing faults; unexpected power disruption; switchboard blow-ups and fires.
The other nine verification requirements must also be addressed in an agreed way to complete the package.
Will you comply?
It may be a challenge as AS/NZS 61439 has six parts (0 to 5 with part 0 being a specifiers’ guide). With a document this large it is not something you can comply with other than with proper verification support. Compliance can be further complicated by different parties having interpretations for some clauses. Also, the unwritten words (what is not being said) may carry as much weight as the written ones.
And don’t forget; there is no AS/NZS 61439 court to interpret or police to enforce compliance. It will be a matter of ‘agreeing to agree’, ‘agreeing to disagree’ or compromising.
This makes it extremely important for the verifier (the assembly manufacturer) to have a clear and an auditable trail for their design verification backed up by a robust set of SOPs (standard operating procedures) to prove compliance in situations where there is doubt.
And if it is anything to go by, collectively such SOPs may involve more than many different checks to prove the system and avoid rework.
All the players; the manufacturers, inspectors, contractors, engineers, specifiers and end-users, may all need to become more involved.
Are manufacturers between a rock and a hard place?
Certainly, especially now as AS/NZS 61439 design verification compliance gains traction. It may be advisable for manufacturers not yet doing so, to educate possibly uninterested users to alter any unreasonable user expectation.
Also, those buyers that are not the actual users but initially making the switchboard selecting decision who may still judge purely on price alone may need to have a rethink.
Ultimately, however, those buyers realising that ‘you get only just what you pay for’ (if that), will come to understand there is considerable merit in sourcing only from respected manufacturers.
Likewise, the manufacturers will come to realise there are some customers not worth working for and so not focus on those.
It will be the respected manufacturers whose efforts will be better rewarded.
Any key do’s and don’ts?
DO NOT under-estimate the complexity of AS/NZS 61439. Certainly don’t jump to conclusions just grabbing one sentence or paragraph to find out later it was only half the story.
The Standard has cross-references in most clauses, many having multiple references. All must be traced and ruled in or out. Even a simple verification process may involve referencing 30-60 clauses for consideration to be ruled in or out with few simple yes or no answers as most are conditional depending on other factors.
DO take the time to gather all the facts before making a decision and follow up every reference in case it affects the outcome. Then so as to not have to re-invent the wheel every time the same question comes up, note how the conclusion was reached and incorporate the information in your operating procedures so there is an audit trail if challenged.
Need more information?
In the next edition it is hoped to give some insight on how to best to use AS/NZS 61439 to both the manufacturers’ and contractor/users’ advantage. Watch this space.