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• 1. Introduction
• 2. The Electrical Safety Act 2002
• 3. The Electrical Safety Regulation 2002
• 4. Risk management
• 5. Operating cranes and plant near overhead electric lines
  • 5.1 Scope
  • 5.2 Regulation requirement on exclusion zone for electric lines
  • 5.3 Exclusion zone
  • 5.4 Risk management process for a crane working near electric lines
  • 5.5 Working in the safety observer zone
• 6. Work near low voltage overhead electric lines
  • 6.1 Scope
  • 6.2 The no-touch and exclusion zones
  • 6.3 Hazard identification
  • 6.4 Risk assessment
  • 6.5 Examining the low voltage overhead line for visual defects
  • 6.6 Deciding on control measures
• 7. Clearing vegetation near overhead electric lines
• 8. Agricultural work near overhead electric lines
  • 8.1 Scope
  • 8.2 Regulation on exclusion zones
  • 8.3 Hazard identification
  • 8.4 Risk assessment
  • 8.5 Deciding on control measures
  • 8.6 Particular circumstances
• 9. Transportation of high loads near electric lines
  • 9.1 Scope
  • 9.2 Meaning of terms
  • 9.3 What is a high load?
  • 9.4 Legislative requirements
  • 9.5 Travel requirements
  • 9.6 Responsibilities
• 10. Repair of electrical equipment
• 11. Work near electrical hazards in buildings and near underground electrical cables
• Appendix A - Meaning of terms used in this code
• Appendix B - Exclusion zones in millimetres

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11. Work near electrical hazards in buildings and near underground electrical cables

11.1 Scope
11.2 Hazard identification
11.3 Risk assessment
11.4 Notes on cable identification
11.5 Control measures

11.1 Scope

This section applies to any work in buildings and near electrical installation or underground cables that involves risk of contact with exposed live parts.

Examples of such work include:

• A builder removing a sheet of plasterboard from a stud wall and thus creating a risk of contact with exposed live parts eg an electrical accessory such as a socket outlet.
• A plumber cutting a water pipe in a building where there could be an electrical cable next to the water pipe.
• A fencing contractor digging holes where an electrical cable could be a buried.

11.2 Hazard identification

Hazardous situations to be considered include:

• Any electric lines or apparatus installed in building cavities that may become accessible when:
  • A part of the building covering the cavity has been removed; or
  • Work is being carried out in the building cavity.
• Conductive material may inadvertently be brought into contact with live parts eg metallic sarking being installed in or removed from a building.
• Work activities that could involve risk of damage to electric line or cables eg drilling or sawing.
• Work done in a building or structure where the existence of electric lines and apparatus is not known.
• Excavating or driving implements into the ground (eg. star pickets) where underground cables may be located.

11.3 Risk assessment

Where a hazard has been identified, a risk assessment must be conducted. The assessment should consider:

• The risk of tools damaging cables or apparatus, for example:
  • when digging, driving equipment or excavating where buried electrical cables may be present;
  • when demolishing part or whole of a building;
  • when installing a building component or material. For example, using screws to fix a bracket to a wall where the screw could penetrate a cable installed behind the wall surface.
• The risk of cables or apparatus being concealed in a work location.
  • If it is not known whether cables, conduits, apparatus or situations form an electrical safety hazard, you should either assume that the hazard exists, or have a qualified person investigate and report.
  • If excavating in a public place, suitable means must be used to identify any electrical cables that could be present. Suitable means may include:
• Call "Dial Before You Dig". This organisation will advise if electrical cables owned by one or more of its contributory members are located near your worksite. In addition, definite cable locations can be determined by special arrangement with the organisations.
• Contact relevant authorities about any cables they may have placed near the excavation. Authorities may include:
  • Distribution entities, such as Energex or Ergon
  • Communication companies, such as Optus and Telstra
  • Local government authorities
  • Water authorities (typically to supply water metering equipment).
• In some instances, customers of distribution entities have authority to place electricity cables in public places. If excavating on private property, you should first contact the owner or occupier of the premises about buried cables.

11.4 Notes on cable identification

Electric lines and cables are manufactured in many different ways. Not all cables are covered with thermoplastic sheath, although these are common and often well known in the building industry.

Electrical cables have different shapes and appearances. For example, cables can be circular, oval, flat, or ribbed in cross section. These cables can also be of any colour.

Some electric cables consist of a copper sheath with copper conductors within the sheath and a mineral insulation separating the conductors and sheath. These cables look and feel identical to copper water pipe or gas pipe. Cables of this kind could also be made of other metals such as stainless steel and aluminium.

Cables in buildings and structures can operate at low or high voltages, eg cables supplying a transformer in a building may be energized at 11,000 volts (11kV). Some installed cables may be exposed but others may be concealed in many ways, for example:

• In wall, floor and ceiling cavities;
• Behind joinery such as skirting boards and pelmets;
• In structural parts of buildings such as hollow steel studs and supporting columns.

Electrical conduits are often made of different materials and constructed differently. Examples include:

• PVC rigid conduit from 16mm or 5/8 inch outside diameter (OD) to 150mm or 6inch OD and generally light grey. If the conduit is heavy duty and suitable for underground use, it may be orange. PVC conduit for protection against high temperatures is black.
• PVC flexible conduit or flexible hose.
• PVC corrugated conduit.
• Screwed metal conduit, generally made from galvanized steel.
• Split metal conduit (obsolete but still widely used) and generally painted black.
• Cable trunking, rectangular or square in cross section, and in a wide range of sizes. Made of steel or plastic.
• Cable tray, generally galvanized steel in a wide range of sizes and styles.

11.5 Control measures

Where the risk is not known, it must be assumed that an electrical hazard could exist. For example, if you cannot determine exactly where an underground cable is, you should dig carefully to avoid accidental damage. This may mean digging only by hand. Where the risk is known-for example, where an electrical conduit contains a live low voltage circuit and there is a risk the conduit could be cut or scraped with a power tool-suitable precautions should be taken. This may mean using hand tools instead of power tools.

The preferred hierarchy of control is:

1. Eliminating the hazard. This could mean having the electricity supply to the circuit isolated. Sometimes, when many cables and circuits come from a switchboard, identifying the isolation point for a particular cable is not easy. It may be necessary to have a qualified person do the isolation work.
   For example, if the work involves building demolition and isolating supply is the control measure, it may be necessary to have the distribution entity disconnect the supply.
2. Substituting with a less hazardous material, or use of a different process or equipment. Instead of welding a bracket to a column, which may result in excessive heat and damage to adjacent electrical cable, it may be safer to bolt the bracket to the column.
3. Redesign equipment or process. This may mean using a less intrusive method of carrying out the activity. For example when cutting a hole for a door through an existing stud and plaster wall, scoring and breaking the plaster rather than sawing it through will reduce the risk of damage to any cables, which may be in the wall.
4. Isolate the hazard. This could mean using a physical barrier to prevent accidental contact between a hand-held tool (e.g. grinder) and the exposed live parts in the wall.
5. Using administrative control. This may include an authorisation and training regime to identify the hazards and perform the work safely.
6. Use of appropriate personal protective equipment may mean use of such as insulating gloves and fire retardant clothing.

Last updated July 16, 2009

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