References: R Record keeping requirement | E An engineering/certification requirement | P A permit to work requirement | S A safe work method statement (SWMS) / written plan

Hazards

• ‘Live’ Electricity
• Electric shock, burns, death
• Contact with overhead electric lines (powerlines); or
• Arching e.g. between electrical source and plant/equipment/materials/structures
• Contact with underground electric lines
• Fire
• Explosion
• Ground collapse/subsidence
• Network asset damage
• Restricted/reduced working area

Planning considerations

• Location, height or depth, arrangement, and visibility of the electric lines (overhead, underground)
• Whether the electric line (overhead, underground) is owned by a network operator / is a network asset
• The type and location of work activities planned to be conducted (i.e. method of excavation)
• The type of plant/equipment planned to be used
• Voltage, insulated or bare and the associated danger zones, minimum approach distances or clearance zones
• Sway or sag of overhead electric lines
• Isolation or mechanical protection measures
• Terrain
• Environmental conditions

Danger Zones / Minimum Approach Distances

A danger zone is a defined area surrounding live electrical assets (overhead electric lines), the danger zone is determined by the voltage.

Minimum approach distances apply for network asset/s (underground cables) for work using power tools or plant, for non-powered hand tool or non-destructive digging. The minimum approach distances are defined by the network operator (see Figure 2).

Work is not permitted in the danger zone of an electric line unless authorised by the relevant authority / network operator and controlled*.

All electrical assets must be treated as ‘live’ unless they are tested & proven to be isolated/de-energised

Overhead electric lines / power lines

The danger zones of overhead electric lines (power lines) are, within

• 0.5 metres of a live insulated overhead electric line or aerial bundled conductor line of a voltage of not more than 1 000 volts
• 1.0 metre of a live uninsulated overhead electric line power line of a voltage of not more than 1 000 volts
• 3.0 metres of a live overhead electric line, whether insulated or not, of a voltage exceeding 1 000 volts but not more than 33 000 volts; and
• 6.0 metres of a live overhead electric line, whether insulated or not, of a voltage exceeding 33 000 volts.

Clearance Zones for Scaffold

Overhead electric lines are a potential hazard where they are in close proximity to persons erecting, modifying, dismantling, working from or in the vicinity of a scaffold.

Where scaffold activities are in close proximity to overhead electric lines, consult with the relevant regulatory authority / network operator.

For voltages of 11kV or less, close proximity is typically a minimum clearance of 4m between overhead electric lines and the adjacent scaffold.

The fitting of non-conductive materials on the outer face of the scaffold adjacent to overhead electric lines may be required by the regulatory authority / network operator.

Underground electric cables / lines

Minimum approach distances for underground electric cables / lines are described in figure 2.