New wiring rules are coming — are you ready?
The new version of the Australian/New Zealand Standard for Wiring Rules is set to be released soon. In the article below, Gary Busbridge, Standardisation Manager at Clipsal and Chair of the Australian and New Zealand committee responsible for the revision, provides an overview on the changes.
The revision of the Wiring Rules has been a long journey that started way back in 2012. Even as we discussed the revision, many on the committee took the proposals to the electrical industry and openly discussed the proposed changes so that we could garner stakeholder feedback. Much of the feedback was used to support some changes and additions, whilst we argued upon the need and justification for the rest. The committee has been as forward-thinking as possible and has debated many issues, brainstormed possible future issues and reviewed current issues.
Over 2000 Public Comments were received on the draft, and a lot of these comments were found to require a fair amount of research before being put into the Wiring Rules, therefore they were put into amendment one storage. Getting to this stage has taken a lot of work and the new edition of AS/NZS 3000 is set to be released in October 2017.
RCDs
There have been some major changes regarding where and when an RCD is to be installed. In residential installations, all final sub-circuits are to be protected by a 30 mA RCD with no exceptions. Of course, the requirement for three final sub-circuits per RCD and the sharing of multiple lighting circuits across RCDs remains.
In non-residential installations, where there is a plug and socket connection to electrical equipment, the final sub-circuit shall be protected by a 30 mA RCD. Where there is fixed wiring direct to electrical equipment, consideration should be given to protecting that final sub-circuit with a 30 mA RCD. The existing exceptions remain in that where it is more dangerous to expose the final sub-circuit to nuisance tripping, the final sub-circuit can be protected by other means. Further to this, an exception has been added where electrical equipment is required to run continuously, in that case the final sub-circuit can be protected by other means. But all final sub-circuits for lighting shall be protected by a 30 mA RCD.
There used to be a reference to “alterations, additions and repairs” but we have removed “additions” as it is an “alteration”. Simply put, an alteration means that the electrical characteristics of the final sub-circuit have changed, for instance the addition of a socket-outlet in a new room changes the length of a cable run, and therefore it is necessary to put a 30 mA RCD on that circuit. Whereas, a repair is a like-for-like replacement of a broken or unusable accessory, meaning that the original protection for that final sub-circuit can remain and is not required to have 30 mA RCD protection. And finally, on RCDs, where all the circuit protection is to be replaced on a switchboard then all final sub-circuits from that switchboard need to be protected by a 30 mA RCD.
Medical installations
There are many revised or new definitions and these provide a sound basis for all your discussion about design and installation. Using the definitions means that all parties in the discussion start at the same point. For instance, we have added a new definition “Accessible” and revised the definition of “Readily Accessible” to ensure clarity regarding medical installations and mounting of electrical equipment.
Further improvements to the emergency egress from a switch room have been made, with clearance requirements to one metre from accessible faces of a closed switchboard and 600 mm from open doors or racked-out equipment. The access/egress door from the switch room has also been increased in size. In an emergency, the increase in distances may save lives.
Mains switches
Mains switches are an important part of any installation and it is essential that a mains switch is operated manually and is not controlled by electronic devices. New wording will clarify this aspect. The last thing needed in an installation is for an override of the mains switch by some programmable device. Manual switching could save lives.
What IP rating does electrical equipment need to comply with when exposed to the weather? A zone for external walls has been created to clarify what equipment can be used where. This zone extends at 30 degrees down from the edge of a verandah or eave to the exterior wall. Any electrical equipment within that 30-degree triangle is deemed protected and does not need an IP rating. All electrical equipment below that triangle requires an IP33 rating as a minimum. Meter boxes are excluded as they have historically been IP23. Any electrical equipment contained within the meter box enclosure does not need an IP rating.
Kitchens, downlights and outbuildings
Kitchens haven’t been forgotten, as there is now a 150 mm zone from either side of the cooktop extending up to the rangehood, ceiling or a height of 2.4 m, in which switches or socket-outlets are excluded. Reaching across hot surfaces to access the switches and socket-outlets is now a thing of the past.
Classifications of downlights are to be marked on the product as well as the packaging. This provides information as to where the downlights can or can’t be installed. These classifications provide helpful information. A handy hint, look for an “IC” or an “IC-4” classification as these downlights can be used anywhere in an installation.
The outbuilding that we all know and understand, as separated by an area of land, will now be renamed an ‘individual outbuilding’. There is a new term — a ‘combined outbuilding’. This term is to define a number of structures that are connected on a single concrete slab, such as multiple residential units on a common slab.
Generation systems and electricity distributors’ equipment are to be kept out of the zones around pools, spas and water features. It is an unsafe practice and can lead to instances where children use this type of equipment as improvised diving boards.
Electricity generation systems have been updated to the latest revision of AS/NZS 3010.
Safety
Lifts for normal conveyancing are considered to be electrical equipment and have their requirements detailed in Section 4 Electrical Equipment. Those lifts deemed to be emergency lifts have their requirements detailed in Section 7 Safety Services.
Section 7 Special Installations has a section devoted to Safety Services and whilst the detailed requirements have not changed that much, the whole Safety Service section has been revised to enable a user-friendly set of requirements. Using it is as simple as heading to the specific section required, for example supply systems, main switchboard, main switches, fire pumps, fire and smoke detection and alarms, air-handling equipment, evacuation equipment or emergency lifts and all the detail will be in that one set of clauses.
Arc fault
We have added detail about the use of Arc Fault Detection Devices (AFDDs) in an installation. These devices look and feel like a 2-pole RCD/MCB but are there to detect and isolate a final sub-circuit that may have a small arc fault generated from broken strands in a flexible cord, fixed wiring or poor termination. This is a very small current but continual arcing would lead to a fire. They provide excellent further supplementary protection to the RCD and are good for protection of wooden structures and bedrooms. They are not mandatory at this stage. These devices are to be fitted after the MCB and RCD on a final sub-circuit. There is an Appendix O in the Wiring Rules with detailed information on installation.
Switchboards
In Appendix E The National Construction Code, more information has been added on the classification of buildings. Recently, Australia has adopted a new range of switchboard standards, so a new Appendix K has been added. This provides several switchboard guidelines to help the electrician to better understand the specific issues to be addressed in manufacture and verification of switchboards.
Appendix M provides some overview for continuation or reliability of supply, especially in those installations that are concerned with the aged and infirm. Just what would happen to incapacitated persons in a building, if power supply was disrupted? This appendix provides some guidelines for your consideration in design and construct.
Electric vehicles
Electric vehicles are becoming increasingly popular and that means electric vehicle charging stations are becoming a part of the installation design. Appendix P provides guidance on the different types of vehicles and installation of the charging stations.
Recently, Australia adopted an international series of standards on electrical conduits that are similar to the existing series of Australian conduit standards, except some marking aspects. Appendix N provides information on marking variations between the two sets of standards.
DC/DC
Lastly, there is a trend that is occurring in the data centre market with DC power being used to run active electrical components within the centre. Who knows where this will go, but you can bet that there will be more of this pushed towards the residential installations over time. Appendix Q has been added to provide guidelines on what to look for when installing DC wiring systems.
Remember, this is an overview of the major changes and additions and doesn’t contain all the detail. When the new wiring rules are published, get yourself a copy and find out just what has changed or added. You may be surprised.
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