The recently published Amendment 3 to the Wiring Rules deals in the main with switchboards and there are plans to revise our switchboard standard in the pipeline. Peter Vandenheuvel looks at all the potentially overlooked savings and business opportunities.

It’s fair to say, for a while there, existing switchboards built by switchboard manufacturers to the previous standard SA/NZS 3439 (and before that to AS 1136) got a bit of an unfair ‘bad rap’, with concern about their poor workmanship and these being a hazard.

However, following considerable investigation, it became clear to me the poor workmanship on show was almost entirely by others due to questionable adding to and making changes after the switchboards were installed.

It also showed the often talked about catastrophic hazards that arose from people (for whatever reasons) accessing switchboards without making them safe, not first following isolating procedures or just not replacing covers or locking doors, so not preventing the accidentally making contact with live parts, often with very serious consequences.

Unfortunately, this probably also included some electricians taking shortcuts and not following the “not working on or near live parts” rule, as well as the owners or users accessing or not restricting access to unlocked switchboards, so allowing them to be accessible to unauthorised persons.

And the fact the switchboards are generally safe is also supported by Amendment 3 of AS/ANZ 3000 where the wording in Clause 2.10.3.2 has been changed, with switchboards complying with AS/NZS 3439 as well as those complying with AS/NZS 61439 now being ‘deemed to comply’, with the requirements of AS/NZS3000 Clause 2.10.3.2 – in place of previously only being ‘considered’ to comply – providing either one or both (a) and (b) listed after this in the clause exist.

However, that doesn’t mean any switchboard owner or user with switchboards deemed as complying with AS/NZS 3149 has a cart-blanch excuse to neglect their responsibility. This is because the overriding responsibility of every owner or user is to ensure their workplace – including their switchboards – is safe. So, quite the opposite, as they – in the unfortunate situation where an incident occurs – will soon discover when they get the inevitable visit from their government’s safe-work people.

And, it is also worth switchboard owners and users noting that in all Australian jurisdictions – and most likely also in New Zealand – any workplace-related electrical shock incident must be reported to the authorities within 24 hours.

In addition, this overriding requirement for the owner or user also extends to the electrician or electrical contractor and their employees. They must all abide by safe work requirements. This includes having a safe place of work, including documented safe working methods, a total ban on working on or near live parts, proper safe work training and restriction of access to live parts for all other than those specifically authorised and trained for safe access.

Why the change?

As noted in previous articles, AS/NZS 61439 is very similar in its requirements for switchboard design and verification to AS/NZS 3439, apart from some additional methods of temperature rise verification and testing, where it has more test and verification options. Unfortunately, these can be difficult for the average user of the Standard to understand.

These added temperature rise test methods are then – theoretically at least – able to be used to ‘build up’ any similar arrangement without further testing, using that test data. But this is only if the switchboard manufacturer has done the testing of various arrangements.

To me, the new Standard seems to go to very great lengths to create extremely accurate test information but then uses it in a way where you still end up with only indicative answers, with again no finite number as proof. So, the results will still only be an indicative temperature rise.

All the other verification and testing between the two Standards is very much similar if not the same and has been the same for many years. As far as ease of use and layout are concerned, AS/NZS 3439 is, again in my opinion, much simpler to follow.

However, to be competitive in world markets, and for major projects in Australia and New Zealand, as well as to have the ability to select world-class equipment, we need to have an internationally recognised standard that is accepted worldwide.

This is a major hurdle to developing our Standards, because due to the extremely limited experienced switchboard expert resources we have, that’s really not an option, as we are already taking up all the available resources we have in that industry to just keep up with overseas IEC Standards changes!

So, it makes much more sense to fall into line with other similar countries, as by adopting world-recognised standards we will at least have the ability and resources to fine-tune these for our Australian and New Zealand country-specific requirements.

The coexistence of the two standards

The dust has now hopefully settled on the ‘sort of’ mutual coexistence of Switchboards to Standards AS/NZS 3439 and AS/NZS 61439 with the publication of AS/NZS 3000 ‘Wiring Rules’ Amendment 3 on 19 May 2023, with clearer guidance as detailed in that Amendment (some of which as above).

This is important, as the industry principle has always been to continue accepting all pre-existing electrical installations built to the Standards applicable at the time they were built ‘as is’, with no changes, recall or rework requirement. Also, any subsequent changes to parts of that existing installation, including for switchboards, up to the new Standards release, would not require that part of the installation to comply with the new Standard.

As an example; this would not need for a complete switchboard assembly built to AS/NZS 3439, or any past changes to that switchboard, to be upgraded or replaced with one to the new standard AS/NZS 61439, but with a small caveat; possibly apart from in exceptional hazardous circumstance.

However, although AS/NZS 3000 Clause 2.10.3.2 now still deems switchboards to AS/NZS 3439 to comply, the industry has also been on notice for more than five years of the move to adopt AS/NZS 61439. And most manufacturers and buyers are now firmly committed to the new Standard.

So, it is certainly my recommendation, even just purely from a marketing perspective, that if there are any switchboard builders still relying only on AS/NZS 3439 verification, they consider aligning their designs with the new AS/NZS 61439 standard in a formal way by using one or more of its three verification methods, preferably by an arms-length expert.

In doing this, given that prior to the introduction of the new Standard, verification and test certification practices were mainly focused on short circuit withstand strength, it would, in my opinion, be wise to focus also in detail on temperature rise in verifying any compliance.

Further, any planned new modification to an existing switchboard includes the verification of the entire current-carrying paths either directly or indirectly affected within the assembly from the point of supply to the outgoing connections to AS/NZS 3149, in particular regarding temperature rise.

Amendment 3

As touched on earlier, this was published on 19 May 2023 and although it also includes some other non-switchboard-related AS/NZS 3000 issues, this Amendment has a major focus on the interaction between the Wiring Rules AS/NZS 3000 and how the Wiring Rules users must apply ‘Low Voltage Switchgear And Controlgear Assemblies’ Standards AS/NZS 61439 and AS/NZS 3439 where called up by it.

There are fifteen elements (separate changes) listed in the three-page Amendment and it is advised these be read, understood and inserted in the correct locations in their Wiring Rules copy as instructed.

Certainly, just ‘parking’ the three A4 pages Amendment (or even its A5 version) loosely in the back of the users’ Wiring Rules copy is not the best way of ensuring it will not be overlooked.

At least a cut and paste of the insertion or a handwritten notation of the change by the user is needed to help draw the users’ attention to what the change is all about.

In doing it this way, the user will also become more aware of the change and hopefully be reminded of it when the changed clause is referenced. As well, it will retain any other notes and comments already annotated by the user in their personal Wiring Rules copy.

There is, of course, also the option of buying the new Wiring Rules version, as it also includes all three Amendments already identified in the margins. However, if the user has already had to outlay the cost for the initial purchase in 2018 and then again for the republished Standard Amendments 1 and 2, this will now be the fourth time the user is faced with a substantial replacement cost and even then, it may still need the user to also to transfer any of their own annotations.

Similar to other Standard Amendments – as opposed to Standard Revisions –Amendment 3 is in an ‘Amendment’ format, which is extremely short and somewhat too much to the point, especially when it deals with delete and or delete and replace issues. This is because it doesn’t show the deleted or to-be-replaced text, only the new text.

This can make it very difficult for the user to understand what the actual change is. So, the reader or user can’t compare the ‘old’ with the ‘new’ without also having both the ‘old’ and ‘new’ versions as well as the ‘short form’ version in front of them. And even then, it is at most times extremely difficult to understand the actual change at first glance.

Certainly, for the more complex, important and ‘big ticket’ change issues, I have found it helpful to copy the entire old clause or sentence with the deleted text (in red and with a line through it) and the new text (in blue) on one piece of paper to get a full understanding.

Normally, I would provide a summary of the changes here, but owing to the brevity of the Amendment, it would just be a repeat of it and as such it may infringe on the Standards Australia and New Zealand copyright.

So why the amendment?

In a nutshell, it was mainly undertaken to clarify and acknowledge that even though AS/NZS 61439, in a roundabout way, supersedes the previous AS/NZS 3439 and is likely to be the key Standard for new works, the ‘old’ Standard must still be recognised as complying, for switchboards in existing installations, especially where these are added to or otherwise modified, as and when needed, without the need for having the entire assembly brought up to compliance with the new Standard.

Although not detailed under the switchboard requirements in AS/NZS 3000 it is my understanding from previous common practice that any alterations and changes to a switchboard must at least comply with the Standards applicable at the time it was installed.

If my understanding is correct, then any alterations and or additions for any switchboards manufactured to AS/NZS 3439, would have to comply at least with the requirements of that Standard and to the Standard AS/NZS 3000 applicable at that time, and for these requirements to apply to all parts of the assembly directly or indirectly affected by the alterations and additions.

It would also be expected that all such compliance of the alterations and additions be verified to that Standard’s requirements.

Revising the switchboards standard

As noted in the introduction, the revision of the Australian and New Zealand-specific switchboard Standard AS/NZS 61439 is also now starting to get up some steam. As may also be noted from comments above, AS/NZS 61439, because it’s not the most user-friendly Standard to use – in my opinion at least – it will be a challenge for Standards Australia and New Zealand Standards ‘Industrial Switchgear and Controlgear Committee EL-006’ to undertake.

The main reason for its structure and complexity is that it’s published by IEC (the International Electrotechnical Commission) to their established format, with input from a very wide range of experts from many different countries – like we in Australia and New Zealand, who are a member – all have some specific in-country situations, electricity distribution systems, environmental issues etc that need to be included.

Because of the complexity of the Standard, the revision process, and the fact we can only make AU and NZ changes, it would be very optimistic to expect a broad range of changes as all those likely to affect other users in other places would also have to input and agree, which will take the process up to at least the next IEC bureaucratic level, if not further.

A list of issues to be considered in this AU/NZS revision is currently being prepared by Committee EL-006 and will no doubt focus on changes made since the last IEC revision, as well as from our AU and NZ experience and feedback since having adopted the new Standard.

Ideally, I would like to also see;

• A wider interpretation or greater flexibility on the way the three verification methods are interpreted as they are meant to be ‘considered equivalent’, enabling more verification by comparison, extrapolation, application of calculations, design rules and industry-recognised reference books.
• More clarification on verification of temperature rise testing methods, with greater flexibility in the use of watts-loss data and use of Standards like AS 60890 Heat Rise Calculation.
• Reintroduction of the Partially Type Tested Assembly (PTTA) concept, albeit perhaps in a more limited way to allow for easier verification of bespoke hybrid type assemblies.
• More emphasis and clarification on the assessment and use of the Rated Diversity Factor (RDF).

It should be noted that AS 60890 Heat Rise Calculation is currently also being reviewed.

Reducing switchboard costs

Now that most (if not all) switchboards being manufactured in Australia and New Zealand are to AS/NZS 61439 and should now have verification to a manufacturer’s tested design, one would assume typical assemblies from one manufacturer would all be very similar. In other words, every assembly should be to the same stringently tested design or designs.

That is, of course, unless a particular switchboard manufacturer has a plethora of tested designs to choose from.

This would, for most manufacturers, even with variants also tested, mean that each is of the same type and that each would have to perform in the worst-case scenario, which could result in many being over-designed, at extra cost to the manufacturer with that cost normally passed on to the buyer (eg. builder or contractor) and their the owner or user.

Now, that’s not a problem if the buyer has dotted all their Is and crossed all their Ts for their specific requirements. But in the switchboard building and contracting world I came from, the buyer at best typically just sends out a single-line diagram with perhaps a short brief and then the all-encompassing “shall comply with AS/NZS 61439” as a blanket requirement.

Now, that’s not so much of a problem when it comes to issues regarding short circuit strength, voltage withstand, switchboard structure and other mechanical types of verification, as all are strictly mechanical and the same designs can be common to many applications.

Also, it’s not so much of a problem with device ratings, as they generally at least fall into frame-size ratings or categories.

But these are also generally not the key cause of switchboard failures.

However, that’s not the case for anything current-carrying related. Here are just some examples where accurate information, as opposed to vague guessing, can reduce costs;

• Providing actual individual circuit current ratings.
• Providing duty cycles for larger circuits.
• Identifying loads prevented from simultaneous operation.
• Nominating realistic IP ratings and internal separation forms.
• Acceptance of internal ventilation.
• Provision of switchroom ventilation or air conditioning.
• Optimising assembly circuit distribution for watts loss.
• More accurate Rated Diversity Factors.
• Optimised selection of cable entries.

All the above can make a substantial difference in determining busbar sizes, compartment sizes, the overall switchboard size, clear space needed around it and thermal performance.

Guessing these and getting the general arrangement wrong could substantially increase the cost.

All these have a cost impact on manufacturing, switchgear ratings, installation and size of the assembly. And although each on its own may only add modestly to the cost, some or all combined can make for a considerable cost reduction.

And it makes sense, after all, the Standard is intended to cover all switchboards throughout Australia and New Zealand, indoors and outdoors, from end to end. So, a default selection will always err on the side of caution and conservativeness and also up the cost if this vital information is not accurately provided.

So how can these costs and other impacts be reduced? Simply, by closer communication between buyer and manufacturer.

To start with, by using the Part 1 Annex C, Part 2 Appendix BB and Part 3 Annex AA schedules to their fullest and being realistic about what is actually needed rather than going for the safety of just calling up AS/NZS 61439 or mistakenly thinking the higher the number the better the outcome.

Typical examples are; specifying IP ratings higher than needed, having unrealistic or over-conservative Rated Diversity Factors (RDFs) and specifying outdoor-type ambients for switchboards in well-ventilated indoor locations or air conditioning. Likewise, by nominating a ‘blanket’ current rating at or near the maximum for the particular circuit protective devices to be installed when most circuits may be well below half that and they are also not all operating at the same time.

Because all these extra requirements will then unnecessarily allow for locking in more heat and prevent its dissipation, so needing manufacturers to uprate busbars and devices, making the switchboard larger and also often shortening its service life.

Here, a bit of extra homework by the specifier can reduce the cost (and maybe the size) of the switchboard considerably. If the information isn’t provided, there should be nothing stopping the manufacturer from including their assumptions in their proposal to offer more competitive pricing and save ‘quarrels’ later.

Further, an understanding of the real installation environment as well as the intended use and expected service life should also be taken into account as they can also make a difference.

Wider business opportunities

We now live in a world where more and more installations with existing AS/NZS 3439 switchboards are now being redesigned to accommodate substantial solar, wind and other ‘renewable’ power supplies, have storage batteries added and supplies to high-current-rated electrical vehicle charging outlets.

In some instances, this will require the replacement of the switchboards, in which case these should be to the new Standard AS/NZS 61439. However, in most instances, it will be more economical and practical to upgrade the existing switchboards. This will no doubt require for many of these switchboards to be modified to accommodate the additional circuits and may also involve increasing their capacity where this is either borderline or below what will be required.

As the main shortcomings in the existing switchboards will most likely be current carrying capacity, it may require some ingenuity and inventiveness of the switchboard changes, but possibly also of its immediate environment, to prevent the modified switchboard from exceeding its temperature limits and so prevent switchboard failures.

This could well be a very good proactive business opportunity for those more entrepreneurial electricians and electrical contractors willing to come up with imaginative but also fully complying solutions.

In addition, as noted earlier, with the obligation for switchboard owners and users to provide a safe workplace, in any situation where switchboard modifications and the like are undertaken, a simple offer of an audit of the safety of the switchboard and its surroundings to ‘make safe’ may also be a new opportunity as part of any switchboard modification works.

So, for getting it right, making savings and new business opportunities, the ball is in your court…