On this page If a boom touches a live line · Plan the line out of the pour · How far is far enough · One person, watching one machine · Tiger tails are a warning, not a shield
If a boom touches a live line
NSW’s code is plain that untrained and unequipped people should not attempt a rescue. Its whole procedure follows, word for word. It is NSW’s; in another state, check that state’s electrical safety regulator.
“In the event of contact with a live overhead or underground electric line or a flash-over between the electric line and a crane or mobile plant, follow these steps:”
- “Attempt to break machinery contact with the live electric line by moving the jib or driving the machine clear.”
- “If breaking contact is not possible, the crane or plant operator should stay inside the cabin or on the plant item. Immediately call 000 and emergency services will contact the Electricity supply authority to isolate power to the live overhead electric line. Don’t panic, remain calm and stay inside the cabin. In case there is an immediate danger, only then should you attempt to break contact.”
- “In cases of fire or life-threatening situations, if it becomes necessary to leave the cabin or operator’s position, jump clear of the equipment. Do not touch the equipment and the ground simultaneously. Move away by hopping or shuffling (with both feet together) at least eight metres from the nearest part of the crane or plant. Avoid running or walking, as voltage gradients in the ground may cause electric shock.”
- “Warn all workers and the public to stay at least 8 metres away from the crane or plant. Avoid touching any part of the equipment and prevent people from approaching or re-entering until the Electricity supply authority declares the site safe. Electricity can flow through the ground, posing a risk of electric shock.”
- “Untrained and unequipped individuals should not attempt to rescue someone experiencing an electric shock. Secondary accidents can occur, leading to additional injuries. If the crane or plant operator is immobilised, ensure electric isolation and site safety before providing assistance.”
- “Notify SafeWork on 131050.”
“Note: When a crane or item of plant inadvertently contacts overhead electric lines circuit protective devices may operate to automatically turn the power off. However, some protection devices are designed to automatically reclose thereby re-energising the electric lines after a short period of time, typically 1 – 4 seconds.”
SafeWork NSW, Appendix C of its code of practice Work near overhead and underground electric lines (May 2026), reproduced unaltered under CC BY 4.0.
Afterwards: the machine and its tyres
After any contact, the code says a competent person should inspect the crane or plant for damage, and any actions they recommend must be done before it goes back into service. It warns that current through rubber tyres can start a hidden process inside them that may end in a tyre explosion, immediately or up to 24 hours later, with a danger area that can reach 300 metres. Its words cover any rubber-tyred crane or plant, and a truck-mounted boom pump is plant on rubber tyres.
“Any rubber-tyred crane or plant involved in an incident with overhead electric lines, leading to electrical discharges or flash-over through the tyres, should be treated as a potential hazard. If there is suspicion of a tyre explosion risk, such as in the case of a mobile crane contacting electric lines, the procedure should include:”
SafeWork NSW, the same code, Appendix C, reproduced unaltered under CC BY 4.0.
- “Parking the crane in an isolation zone with a minimum 300-metre radius.”
- “Evacuating all persons from the area and restricting access to the isolation zone for 24 hours.”
- “Alerting fire-fighting services.”
Plan the line out of the pour
Before a boom pump or crane works on a site, NSW’s code says the operator or the business must inspect the workspace for live overhead lines, and that operators should assume all overhead electric lines are live unless the electricity supply authority has given an access permit or written documentation.
Turn it off, move it, or use a different machine
- Talk to the electricity supply authority about de-energising the line, or re-routing, relocating or undergrounding it; consider working when the supply can be off, and whether just the section near the work can be switched off.
- Arrange it early, because Queensland’s concrete pumping code warns it can take time, and get written confirmation from whoever controls the line before work starts.
- Safe Work Australia’s own example of removing the risk: use a line pump instead of a boom pump where a boom could contact an overhead line.
If the line stays live
Queensland’s concrete pumping code says a boom should not be operated over the top of energised lines, because its shape and height leave little separation, it moves with the pumping, the wind and its own bounce, and spotters on the ground find distances hard to judge. NSW’s code lists ways to keep a machine clear: plant that cannot reach the approach distance, mechanical stops or zone-limiting devices, setting up so the machine’s whole working envelope stays outside the distance, outriggers and packing to stop unexpected movement, and barriers or bunting marked out under the lines with the supply authority.
Queensland’s risk assessment also asks you to assume materials are conductive unless a competent person confirms otherwise, and to allow for the ground moving, the wind, and lines that sway in wind and sag as temperatures change. Two moments it singles out: keep pipes parallel to the ground when unloading and setting up near lines, and watch the lines at the end of the job when the boom swings away for cleaning out.
How far is far enough
NSW and Queensland each set their own distances. For a concrete placing boom, Queensland’s concrete pumping code asks that workers, every part of the boom and the drop hose stay at least three metres from lines up to 132kV, with greater distances above that. The electricity entity can ask for more than the regulation’s distances if it judges the risk calls for it.
| Line voltage (phase to phase, AC) | NSW | Queensland |
|---|---|---|
| Up to 132kV | 3.0 metres | 3.0 metres |
| Above 132kV, up to 330kV | 6.0 metres | 6.0 metres |
| Above 330kV | 8.0 metres | 8.0 metres, for lines above 330kV up to 500kV |
Closer work needs trained people, a safety observer and, in NSW, a risk assessment first and consultation with the supply authority where that assessment calls for it. In Queensland, an authorised or instructed operator without a safety observer or another safe system is treated as untrained, so the larger distances apply.
| Line voltage (phase to phase, AC) | NSW | Queensland |
|---|---|---|
| Low voltage, bare conductors | 1.0 metre (up to 1,000 volts) | 1.0 metre |
| Above low voltage, up to 33kV | 1.2 metres | 1.2 metres |
| Above 33kV, up to 66kV | 1.4 metres | 1.3 metres up to 50kV; 1.4 metres above 50kV up to 66kV |
| Above 66kV, up to 132kV | 1.8 metres | 1.8 metres |
| Above 132kV, up to 220kV | 2.4 metres | 2.4 metres |
In NSW, anything closer than the Table 2 distances, or above the lines, is the no-go zone: no person, material, crane, vehicle or mobile plant may enter it without the electricity supply authority’s written approval, and the letter should be on site.
One person, watching one machine
A safety observer, often called a spotter, watches the plant and warns the operator before any part of it comes close to a line. The two codes describe the role in much the same way:
- Positioned to see the work, and able to talk to the operator straight away.
- Keeps everyone outside the approach distance, apart from a rescue under approved procedures or a task written into the safe work method statement.
- Does no other work while observing, not even passing tools or materials.
- Watches one work activity, or one machine, at a time.
- Has the authority to stop the work at any time.
- Is trained for the role.
- In Queensland, marks the edge of the exclusion zone with markers the operator can see easily, such as red warning tape.
Queensland’s concrete pumping code adds that a spotter should know the pump’s movements and their limits, and give the operator enough time to respond.
Tiger tails are a warning, not a shield
Tiger tails are sleeves the electricity supply authority can fit to mark exposed low voltage lines. NSW’s code says they give a useful visual warning but should not be treated as protection, mechanical or electrical. Queensland’s concrete pumping code says the same in its own words: they do not insulate the wires, and the exclusion zone still has to be kept.
Where they are used, NSW’s code asks that they extend at least 5 metres beyond the machine’s operating zone, that a competent person checks them visually each day before work, and that the supply authority is called if they move or are damaged. It also asks for equipment for electrical fires, first aid equipment and an emergency and rescue plan on site.
Where to check The codes this page reads: SafeWork NSW’s code on work near overhead and underground electric lines and Queensland’s Electrical Safety Code of Practice for working near lines. In other states, ask the work health and safety regulator, listed by Safe Work Australia.