Electrical practices — construction and demolition sites fact sheet

The standard sets out minimum requirements for the design, construction and testing of electrical installations that supply electricity to appliances and equipment on construction and demolition sites, and for the in-service testing of portable, transportable and fixed electrical equipment.

Work carried out on electrical installations used on construction and demolition sites must also be carried out in accordance with AS/NZS 3000 Electrical Installations (known as the Australian/New Zealand Wiring Rules), except as varied by AS/NZS 3012:2010 where applicable additional controls apply.

Supply

(Refer to section two of AS/NZS 3012:2010)

Construction wiring must be supplied from:

• electricity distributor's main
• existing switchboard in the permanent installation of the premises
• low voltage generator complying with AS2790 installed in accordance with AS 3010: 2017 Electrical installations - Generating sets, or
• inverter complying with the requirements of AS/NZS 4763: 2011 Safety of portable inverters.

Construction wiring (Construction and demolition wiring) means wiring systems installed to provide electrical supply for construction and demolition work, and is not intended to form part of the permanent electrical installation. The term includes:

• consumer mains and sub-mains supplying site switchboards
• sub-mains to site facilities in which electricity is used, such as sheds, amenities or transportable structures
• final sub-circuits connected at circuit-breakers on a site switchboard, supplying plant, construction equipment such as temporary construction lighting, auxiliary socket-outlet panels, hoists, cranes, and personnel lifts.

Construction wiring does not include flexible extension cords or flexible cables such as Extra Low Voltage (ELV) cables - voltages not exceeding 50 V a.c or 120 V d.c used to connect portable plug-in electrical equipment or luminaries.

Construction wiring must:

• not be tied, bundled, or grouped with permanent wiring
• not be fixed to free standing fences that have no fixed posts (or equivalent means of support)
• be positioned to avoid crossing roadways or access ways where cranes, high loads or heavy machinery may travel. If this is not possible, an effective means to minimize the risk of vehicular contact with the overhead wiring system must be provided (such as insulated flagged catenary wires six metres on either side of the overhead wiring and 0.6 m below the lowest point of the overhead electrical cable). All construction wiring, including overhead type, must be insulated.
• be readily distinguishable from permanent wiring by using cable sheaths of a different colour or by attaching iridescent yellow tape spaced at intervals not exceeding 5 m and marked with the words ‘construction wiring’. If live permanent wiring is located where construction activity is occurring it, or its location, shall be marked as live with the words ‘live wiring’ at intervals not exceeding 5 m. Live permanent wiring shall be readily distinguishable from construction wiring.
• NOTE: Particular care should be taken with permanent wiring located in ceiling spaces and under floors. All permanent wiring should be considered to be live until proven otherwise by a licensed electrician.

Mechanical protection of construction wiring - consider:

Step 1 - You should undertake a Risk Assessment. Ensure any Safe Work Method Statement (SWMS) is reflective of the work to be undertaken.

Step 2 - If the risk assessment identifies a risk of damage to construction wiring, then implement suitable measures to relocate the wiring or provide means of protection not less than a – e below. If the risk assessment identifies no risk of mechanical damage, installation continues in line with AS/NZS 3000 Wiring Rules

If a risk assessment is not undertaken, then implement suitable measures of protection not less than a-e below

1. medium duty rigid or corrugated conduit of insulating material;
2. heavy-duty rigid or corrugated conduit of insulating material;
3. flexible electrical hose;
4. armoured cable; or
5. other means that provide equivalent protection against mechanical damage.

NOTE: For further guidance refer to AS/NZS 3000 Appendix H.

Note: The following is a list of examples (but not limited to) where mechanical protection may be required:

1. on any surface within 2.5 m of the floor or ground level
2. on any surface and within 150 mm of, or attached to, scaffolding
3. on formwork decks
4. under a concrete ceiling slab more than 150 mm away from the juncture of the ceiling slab and a wall or beam that would otherwise provide protection
5. within 150 mm of unearthed metal structures being installed as part of the construction process (eg sheet metal ducts and hydraulic piping)
6. across the top of transportable structures, storage containers, shipping containers or the like
7. across or over metallic roofs or edges
8. in adverse environments

Switchboards installed on construction and demolition sites

(Refer to section 2.3 of AS/NZS 3012:2010)

Switchboard installation and location:

• be installed in accordance with AS/NZS 3000 Wiring rules
• be readily accessible and must be protected from damage during the course of the construction or demolition work
• be mounted on a pole, post, wall, floor or other structure of stable and free standing design that takes into account any external forces that may be exerted on the switchboard
• be marked with the source of the supply and where it originates from
• multi-level buildings, be positioned in a manner that eliminates the need for flexible cords or cables to be run between floor levels.

Switchboard construction

Note: switchboards used during construction/demolition that are intended for permanent use once the job is completed, must comply with AS/NZS 3000 and AS/NZ3012

• Switchboards must be constructed of robust material capable of withstanding damage from influences that may be expected at the location.
• The enclosure of the switchboard must have a minimum degree of protection of IP23^a.
• Energised (live) parts must be effectively protected at all times against contact by workersand others.
• An insulated or covered tie bar must be provided for anchorage of flexible cords to prevent strain on the plugs and socket outlets.
• Switchboard doors must not be of the removable type (unless with a tool) and be fitted with a locking facility (for locking overnight or when not in use). They must also be fitted with means for retaining the door in the open position.
• Switchboards must have a cut out (not sharp to prevent cables being cut, ie by providing brushing or plastic hose around it) in the bottom plate to allow safe entry of electrical leads with the door closed. A label must be fixed to the switchboard stating 'KEEP CLOSED – RUN ALL LEADS THROUGH BOTTOM'.
• If more than one switchboard is located on a site, markings must be provided to distinguish one switchboard from another.
• Switchboards must be marked with an electric shock symbol and a danger sign (as per below) warning workers of the presence of energised or live parts within the switchboard.

Isolating switches, RCDs, socket outlets, auxiliary socket outlet panels, portable socket outlet panels, generators and inverters

(Refer to section 2.4 – 2.6.12 of AS/NZS 3012:2010)

Isolating switches/main switches

• Each switchboard must be provided with one marked isolating switch which, if switched off, will interrupt supply to all final sub-circuits and sub-mains originating from the switchboard, including socket outlets mounted on the switchboard.
• The switchboard must be provided with a means to prevent electrical equipment from being inadvertently energised while undertaking work on electrical installations (provision for fitting a padlock or located within a lockable space or enclosure).
• Main switchboard isolating switches must be marked 'MAIN SWITCH' and the distribution board isolating switches must be marked 'DISTRIBUTION BOARD ISOLATING SWITCH'.

RCDs^b

• All final sub-circuits of construction wiring must be protected at the switchboard where the sub-circuits originate by a residual current device (RCD), with a maximum rated residual current of 30mA, that operates in all live (active and neutral) conductors.
• All appliances, luminaries and other electrical equipment must be supplied from an RCD protected circuit that is fixed at the switchboard or incorporated into the socket-outlet or incorporated into a portable socket-outlet assembly.
• All RCDs are to be of type A.

Socket outlets

• Socket outlets must be rated at not less than 10A.
• Single-phase socket outlets must be individually controlled by a double-pole switch (active and neutral conductors are switched) in the following situations

1. Portable generators of the isolated winding type fitted with integral socket-outlets;
2. Portable inverters of the isolated type fitted with socket-outlets;
3. Portable socket-outlet assemblies;
4. on or in transportable structures that are connected to supply by a flexible cord and plug; and
5. Socket-outlets on equipment that is supplied by means of a plug and socket.

NOTE: Socket-outlets may be either the type with a manual switch or an integral switch that switches on when the plug top is inserted and switches off when it is removed.

Portable socket outlet assemblies (PSOA)

• must comply with AS/NZS 3190 and be of class H (should be marked with these requirements)
• must comply with AS/NZS3012 Clause 1.4.17 Portable socket outlet assemblies
• must have an overload protective device, RCD and plugs intended for connection of low-voltage socket-outlet
• flexible cable feeding the PSOA must be the heavy duty sheathed type not longer than two metres.

PSOA Example

Auxiliary socket outlet

Assemblies must be:

• of robust construction to withstand mechanical damage and have a minimum IP23 rating
• located at a height of 1.2 to 2.0 metres above the floor level and be securely mounted to a fixed structure or a structure designed for that purpose
• supplied by an RCD protected circuit at the switchboard it originates from
• provided by a clearly marked 'isolating switch' that controls the incoming supply. Incoming supply cable must have a minimum cross sectional area of 4mm²
• provided by means to relieve strain on plug and socket outlets of flexible cables.

Example of an Auxiliary socket outlet

Cord extension sets (commonly known as extension leads)

• A flexible cord must be the heavy duty sheathed type (not green in colour) and each conductor in the flexible cord must be no less than 1mm² in cross-sectional area.
• The plug and socket on either side of a cord extension set must be compliant with the relevant standard for their construction.
• The maximum length of a flexible cord, for a given conductor cross-sectional area, must comply with table one below.
• A cord extension set must not to be joined so that the total length of any combination exceeds the relevant maximum value specified in table one.

Note: Electrical portable outlets devices (EPODS), for example domestic type power boards, double adaptors and three pin plug adaptors (piggyback), are not allowed on construction and demolition sites.

Table one: (Maximum lengths of flexible cords and flexible cables) as per AS/NZS 3012:2010 Electrical installations – construction and demolition sites.

Generators and inverters

• Low voltage generators (complying with AS 2790) must be connected in accordance with AS/NZS 3010:2010.
• All sub-mains, sub-circuits and switchboards supplied by a generator must be protected as per requirements outlined in this summary.
• Generators and inverters providing electrical supply via permanently connected RCDs must have a maximum tripping current of 30mA
• Isolated winding generators and isolated inverters must only be used to supply a separated circuit for electrical equipment installed in accordance with AS/NZS 3000 Wiring rules, and each winding must supply not more than one item of Class I (earthed conductive parts) electrical equipment.

Lighting, lift shafts, transportable structures

(Refer section 2.7 – 2.9 of AS/NZS 3012:2010)

Lighting

• Where more than one lighting circuit is installed, the lighting circuits must be distributed between RCDs.
• The recommended minimum lighting level for walkways is 40 lx, and 160 lx^c for general areas.
• Lamps in luminaires must be protected against mechanical damage.
• Sufficient lighting must be provided in locations including stairways, passageways and next to switchboards to allow safe access and exit.
• Edison screw type lamp holders must be connected to the supply with the neutral conductor connected to the outer contact.
• Festoon lighting must be connected to an Extra low Voltage power source (<50 V a.c). It must be suspended at a minimum height of 2.5m or above or directly below the ceiling.
• Portable luminaries (eg flood light tripods) must have a minimum degree of protection (refer to AS 60529), a mechanical guard on the lamp and adequate stability.

Note: where components of a proprietary emergency lighting system are replaced with components that are not supplied by the original equipment manufacturer. All of the following conditions must be met:

• Ensure all emergency lighting requirement under AS/NZ 3012 clause 2.7.3 can still be met
• Obtain manufacture’s written approval to confirm the installation can still meet its designed operating range and functions.

Lift shafts

• Construction wiring dedicated to the installation of lift shaft equipment must be fed from a separate final sub-circuit at the switchboard and protected by 30mA RCD.
• Circuit breakers must be locked and tagged to prevent the inadvertent isolation of supply to the lift shaft by others onsite.
• False cars (guided work platforms) must be supplied from a minimum 230V, 20A socket outlet on a final sub-circuit protected by a 30mA RCD. Supply cable must be of the heavy duty type, minimum conductor size 4mm². The supply cable must be installed in a way to prevent mechanical damage and of sufficient length to cover the full length of the lift shaft.

Transportable structures

Electrical installations of transportable structures must comply with AS/NZS 3001.2 and the following:

• The installations must be supplied from a sub-main or final sub-circuit originating at a circuit breaker on a switchboard and installed as construction wiring.
• The installations must be supplied from a flexible cord and plug with a specific socket outlet with a degree of protection not less than IPX4. They must also be individually protected by a circuit breaker of a rating not greater than the socket outlet and be RCD protected. The supply cord must have a minimum cross sectional area of 2.5mm² and be no longer than 15 metres.
• All socket outlets (inside/outside) must be RCD protected and only be used for equipment and lighting within the transportable structure or immediately adjacent to the exterior. (Note: double pole switches must be used for socket outlets.)

Note: Internal wiring within transportable structures is not considered construction wiring.

Inspection, testing, record keeping

(Refer to section 3.1 – 3.10 of AS/NZS 3012:2010)

Inspection and testing

• All construction wiring (both on construction and demolition sites), switchboards and transportable structures must be inspected and tested in accordance with AS/NZS 3012:2010 by a licensed electrical worker (electrician) prior to energisation and re-inspected (visual inspection) in a period not exceeding six months (refer to table 6).
• For new equipment, prior to the initial introduction it must be inspected for obvious damage before being placed into service.
• All other electrical equipment including power tools, flexible cords, cord extension sets (extension leads) and portable socket outlet assemblies and portable RCDs^b must be tested and inspected according to the methods in AS/NZS 3760 and in a period not exceeding three months. Inspection and testing can be carried out by a competent person (trained in use of RCD testers and Portable Appliance Testers PAT) or a licensed electrician.
• ^bThe RCD tests referred to above, test the tripping time which should be less than 300ms. A push button test is required every time a portable RCD unit is used, and monthly on fixed RCDs. This could be carried out by the user (worker) after being instructed on how to do it.
• For hire equipment, inspection prior to each hire and testing at not greater than monthly intervals. If hire equipment remains on site, then table two applies.
• Compliant equipment and equipment new to service must be fitted with a durable non-metallic tag that clearly states the date it was inspected and the next date of inspection. It should also include the name of the person that performed the verification and the standard it was tested to (AS/NZS 3760). Colour coded tags for each period are optional.
• Non-compliant equipment must be withdrawn from service immediately and labelled with suitable warning against further use. If sent for repairs, it must be re-tested and tagged by an authorised person once returned to site.

Record keeping and notification

Records of inspection and tests must be kept for the duration of the construction/demolition job. The following should be recorded and be available for inspection at all times.

• Register of all equipment.
• Record of formal inspections and tests.
• Repairs register and record of faulty equipment, where applicable.

Safety and compliance testing for construction wiring should be recorded on the Certificate of Compliance – Electrical Work (CCEW) form. The form must include:

• visual inspection date, checklist as per AS 3000,
• continuity of earthing system – values obtained for mains earth, bonding earth and protective earth,
• insulation resistance value,
• polarity - checklist, and
• RCD trip time values.

The CCEW should be sent, as soon as practicable but not later than 7 days, by the electrician to:

1. The customer for whom the works is undertaken (i.e. principal contractor),
2. The network owner for the new or upgraded connections to the electricity network or work on switchboards where circuits are being added or upgraded
3. Building Commission NSW

Note: When the electrical installation is a stand-alone system, i.e. from a generator and not connected to the grid, a copy of the CCEW form is not required to be supplied to the network owner.

Note: Electronic records (ie computer databases, excel spread sheets etc) are acceptable.

Table two: Periodic verification intervals (AS/NZS 3012:2010)

Appendix one – Guide to arrangement of switchboards, construction wiring and equipment

Notes:

1. AS/NZS 3000 applies to safety services.
2. If safety services are supplied downstream of this switch, lock this swtich in the ON position and mark it 'Isolating switch - operation by authorized persons only'. If there are no safety services, this is the main switch.
3. Main switch if switch (2) is not provided.
4. Safety service.
5. Only the main switchboard may supply safety services.

Refer to Appendix J of AS/NZS 3012:2010

Appendix two – AS/NZS 3012:2010 – Electrical installations: construction and demolition sites checklist

Inspection checklist

For more information and guidance material on construction work carried out in the vicinity of overhead wiring that is not classified as construction wiring, see the SafeWork Australia guidance material on working in the vicinity of overhead and underground electric lines.

The SafeWork NSW guide on work near underground assets provides more information for work carried out near underground assets (eg power lines, telecommunications, gas, water) and our page on power lines has useful information including a video on working near underground assets.

^a Note: IP23 refers to the degree of protection provided by the enclosures of electrical equipment. According to AS60529 Degrees of protection provided by enclosures (IP Code), IP23 refers to an enclosure (in this case an electrical switchboard) that is protected against access to hazardous parts with a finger and also protected against water spraying.

^b Note: Testing and inspection requirements are discussed further in this fact sheet.

^c Note: lx: 'lux' which is a measure of light illuminance and could be measured using a special hand held device.

Note: Where Standards are referred to in WHS laws they generally refer to a particular version of the Standard. This means the requirement refers to that version and duty holders will need to continue complying with that version of the Standard unless the laws are amended to refer to the updated version.