Electrical wiring on construction sites

Legal requirements

Electrical installations on construction and demolition sites must comply with:

  • AS/NZS 3000 Electrical Installations (known as the Wiring Rules)
  • AS/NZS 3012 Electrical installations – Construction and demolition sites.

The following information explains basic requirements for construction wiring on construction and demolition sites according to AS/NZS 3012.

What is construction wiring

Construction wiring is defined in AS/NZS 3012 as a system of wiring that is installed to provide electrical supply to construction and demolition work which is not intended to form part of the premise’s permanent installation.

It includes:

  • consumer mains and sub-mains supplying construction switchboards, sheds and amenities
  • final sub circuits connected to power points, lighting, construction plant and equipment.

Installation

Construction wiring shall be supplied from:

  • an electricity distributor’s main, or
  • an existing switchboard in the permanent installation of the premises, or
  • a low voltage generator

It must not be:

  • tied to, bundled or grouped with permanent wiring
  • attached to free standing ‘temporary’ fencing panels.

It must be readily distinguishable from permanent wiring, generally by using iridescent yellow tape marked with the words ‘construction wiring’ at intervals no more than 5 metres apart.

Overhead wiring

Overhead wiring should be positioned to avoid crossing roadways or access ways used by plant and machinery. If this can’t be avoided, locate the wiring to reduce the risk of contact: for example, by placing flagged catenary wires 6 metres on either side of and at least 0.6 metres below the overhead wiring.

Protecting the wiring

If there is a risk of damage to cables, and the cables can’t be relocated to a protected position, you must use a suitable enclosure or barrier: for example, a medium or heavy-duty rigid /corrugated conduit, armoured cable, or flexible electrical hose.

Wiring may require mechanical protection where run:

  • on exterior surfaces including roofs
  • in close proximity to scaffolding
  • in risers that may be accessed for various tasks
  • under slabs up to 150mm from a ceiling wall juncture.

Inspecting and testing

Prior to initial use, construction wiring must be inspected and tested by a qualified person in accordance with AS/NZS 3000.

Construction wiring should also be visually inspected by a qualified person to verify the integrity of the installation every 6 months. If any damage or non-compliance is found, requires the relevant part must be isolated, repaired or replaced and tested as necessary.

Records of test and inspections must be kept and available for review.

Permanent wiring

Where permanent wiring is located where construction and demolition work is being done, it shall be considered as energised/live until verified to be isolated/dead.

All energised permanent wiring shall be suitably identified as ‘live wiring’ at intervals not exceeding 5 metres.

Permanent wiring should be assessed for any risk of receiving mechanical or environmental damage from work on the construction site. If it is found that the wiring could be damaged, it must be protected.

Resources

WorkSafe Tasmania resources

Managing electrical risks in the workplace code of practice

Other resources

SAI Global (external link) for the Australian Standards referred to here.

Updated: 29th January 2020