Some electrical installations have particular requirements when it comes to safety.

Electrical installations deemed ‘special electrical installations’ are covered in Section 7.

The categories include: safety services, generating systems, protection by electrical separation, extra-low voltage and high voltage, and explosive hazards.

It should be noted where this section does not specify a requirement, the relevant requirements of the other sections of AS/NZ3000 apply (and these may also call for compliance with other Standards).

Emergency lifts, the only lifts now deemed as safety services, figure quite prominently in this section and in the changes.

This is one of the sections with a large number of changes, although this may not be reflected in the changes listed in the preface as summarised immediately below. For this reason, users would be well advised to come up to speed with this section.

Changes listed in the ‘preface’ include:

• complete restructuring of safety services and their requirements;
• clarifications for the installation of electricity generating systems;
• addition of electric vehicle charging systems; and
• revision of specific electrical installation requirements.

Substantial changes from the 2007 edition in Section 7, in page order, include:

• Under ‘safety services’ the heading ‘scope’ is changed to ‘scope and general’, the existing heading ‘scope’ is included as a sub-heading and the first paragraph previously under ‘general’ is now directly under ‘scope’. (p363)
• Subheading ‘general’ now heads up the rest of the clause. The various exceptions are listed 1 to 6 below the heading for situations that need not comply with this section. The exceptions include, but are not limited to, escalators, moving walkways, single-resident lifts, lifts not defined as emergency lifts, jacking pumps, fire alarms with battery back-up and smoke alarms in private residences. (p363)
• New notes are listed for cross-reference to AS/NZS3009 for power supplies in hospitals. ‘Safety systems’ in part replaces the previous edition’s ‘emergency systems’. This also includes ‘emergency equipment’ in the National Construction Code and NZ Building Code. Some information on ‘fire-resistance levels’ (FRL) is included. (p363 & p364)
• The safety services part of this section has had a complete make-over to make it more easily and logically searched, read, understood and followed. Because it has undergone such drastic change from the previous edition, users are urged to become acquainted with these requirements urgently. The new arrangement following on from the above follows below, in the order they appear; (p363 to p384)
• ‘Supply systems’ notes the additional requirements for wiring safety services – these cannot be used for other purposes. Also, when safety services are required under emergency conditions it may be necessary to automatically disconnect (i.e.: load-shed) non-essential equipment.
• New Figure 7.1 is included for wiring system classification of lift circuits (author’s note: for ‘emergency lifts’, as these are the lifts for safety services). Details on ‘wiring systems – for safety services – (mains, sub-mains, main switchboard and supplies to outbuildings)’ WS classifications are detailed and required to comply with AS/NZS3013. ‘Alternative supply systems’ are also included. (p364 to p367)
• ‘Main switchboard and switchgear’; requires a safety service to be controlled by a main switch separate from other main switches. Safety services must be separated by metal barriers. Conductors for safety services must be separate from other safety services and from other services. Load-break switches for isolation or circuit breakers (discriminating with others in the supply circuit) must be used. Typical arrangement line diagrams have been included. (p367 & p371)
• The clause ‘main switches’ has been redrafted. There is still no limit on the number of main switches, but each must be separate from other main switches for other parts of the installation. Each must be mechanically protected, identified as a main switch in a contrasting colour and marked ‘in the event of a fire do not switch off’. (p371 to 373)
• ‘Fire pumps and fire control equipment’ is substantially edited. These must also comply with AS/NZS3013. It applies to booster pumps, automatic sprinkler system pumps, fire pump rooms, fire pump control equipment and pumps for fire hose reels. (p373 to p378)
• ‘Fire and smoke detection equipment and fire alarm systems’ is substantially edited. It applies to fire and smoke detection equipment, fire indicator panels, fire and smoke alarm systems and warning and intercom systems. (p377-378)
• ‘Air-handling systems’ must comply with AS/NZS3013. There is a cross-reference to Appendix H regarding the WS system. Segregation for cables is required. No switch is to be interposed between a main switch and downstream switchboard. (p378-379)
• ‘Evacuation equipment’ must also comply with AS/NZS3013. This must include sound systems and intercom systems to be compliant with AS1670.4. Emergency evacuation and lighting requirements are provided for in the National Construction Code or NZ Building Code. (p379-380)
• ‘Emergency lifts’ are safety services in Australia. Compliance with AS1735 is not a requirement of AS/NZS3000 but regulatory authorities may require compliance with that Standard or may have additional requirements. In NZ, lifts required for fire-fighting or other emergency purposes are safety services. Emergency lifts must also comply with AS/NZS3013. In addition, no switch is to be interposed between a lift main switch and the downstream switchboard. (p380-382)
• ‘Emergency motor-room less lifts’ are lifts that do not have a lift motor room. Where these are installed for evacuation, fire-brigade activities and emergency use they must comply with this requirement. (p382-384)
• Item (b) under ‘electricity generation systems’, ‘general’, ‘stand-alone system’ is redrafted and now lists typical systems in (i) to (iii). Item (c) has been renamed ‘inverter system’. Its intent has not changed. (p384)
• The new heading ‘basic protection and fault protection’ is added under ‘control’, requiring provision to be made for all basic and fault protection (including MEN) connections to remain intact when supply from the output of the generator is available. (p386)
• A requirement is added directly under ‘isolation’, ‘general’ that an inverter or regenerative supply source shall not be connected downstream of the generating set changeover device. An exception is also included. (p385-386)
• The sentence immediately under ‘over-current protection’, ‘electricity generation system protection’, is expanded to require this to be in line with applicable Australian and NZ Standards for the particular generation system being installed and where the Standard does not specify that the further requirements detailed thereunder apply. The exception below this in the previous edition is now to apply only to a new (a), and is immediately below that item. The paragraph that was below the exception is now the new item (a). The sentence that was below the paragraph – was item (a) – is now (b) and is reworded with additional detail but its intent is not changed. (p387)
• There are changes under ‘connection to electrical installation’, ‘alternative supplies’, ‘general’. The previous (b) has now become (a) but the text is not changed. The previous (a) is now (b) and the previous text and note are now a single paragraph with no material change. The note that was under the previous (b) has been added as a further paragraph (not a note) under the new (b), so changing what it applies to. The note (c) remains. The exception is also changed to be in two parts. The first part ‘1’ is now for Australia only, with the only change being that (i) to (iv) are now bullet points. The second part ‘2’ is a new requirement for NZ only dealing with connections without an N-E link when the installation is operating from an alternative supply. (p389)
• There are minor changes under ‘connection to electrical installation’, ‘alternative supplies’, ‘switching’, which is rewritten to include a previous note and the references are rehomed. There is no change of intent. (p390)
• Figures 7.3 to 7.6 have been renumbered and redrafted in colour, but no intentional change has been introduced. (p391-394)
• The previous ‘notes’ to (the 2007 edition) Figure 7.5 that were between ‘grid-connected inverter systems’ and ‘stand-alone power systems’ (previously p314) are not included. (p395)
• The new heading ‘variable speed drive (VSD) EMI filters’ requires (where these are used) that they must not reference the frame of the system, and optimally only one filter should be used on an isolated supply with multiple VSDs. It also notes that these filters when referenced to the frame may cause harmful capacitive coupled currents. (p399)
• Note 2 in Figure 7.8 dealing with separated (isolated) supplies is reworded to include that circuit breakers may operate in all live conductors or HRC fuses in all active conductors. (p401)
• Reference Standards under ‘Standards containing additional requirements’ that are changed in this edition include those for, high-voltage installations, generating sets, inverters, low-voltage switch and control gear assemblies, stand-alone power systems, PV arrays, secondary battery systems, mobile medical facilities, floor and ceiling heating, explosive atmospheres and hazardous areas. Other text may also be changed, and users are urged to check. (p411-412)
• Reference standards under ‘Standards containing guidance’ that are changed in this edition include those for emergency supplies in hospitals, lightning protection, UPS systems, semi-conductor power converters, rotating electrical machines, periodic verification and verification guidelines. Other text may also be changed, and users are urged to check. (p412-413)
• The new heading ‘supplies for electric vehicles (NZ only)’ has considerable detail and also references Appendices P and C. NZ users are urged to become familiar with these requirements. (p413-415)