Key takeaways
- A safe approach distance is the closest any part of the plant, the load or its rigging may come to an overhead line, and it applies to the whole swept path rather than the machine’s resting position.
- The distance that matters is set by the line’s voltage and by the network operator or regulator, so it must be confirmed from the current source rather than assumed from a previous job.
- Exclusion zones should be marked on the ground in the planning stage, because once a crane is set up the operator cannot see the line above the boom head.
- De-energising and isolating the line with the network operator, or re-sequencing the work so the lift never enters the zone, is a higher-order control than a spotter with a radio.
- Contact incidents surface as prosecution, network damage costs and programme delay long after the lift, and the principal contractor carries the duty to plan the movement before plant arrives.
Overhead line contact is one of the few hazards on a residential site that can kill the operator and the person guiding them in the same instant. The current does not need the machine to touch the conductor. At working voltages it can arc across an air gap, and the person standing on the ground holding a tag line or a spotter’s radio is in the current path once the machine is energised.
That is why the control for overhead lines is not vigilance. It is geometry: deciding, before the machine arrives, where the load can travel and where it cannot. A safe approach distance is the closest any part of the plant, the load or its rigging may come to the line, and it applies to the whole swept path of the lift rather than to wherever the machine happens to be sitting.
This article deals specifically with overhead line clearances and load movement. Temporary site power, leads, tools and RCDs are covered separately in our article on electrical safety for temporary site power, and general site electrical hazards are covered in electrical safety on construction sites.
Why the distance is a property of the lift, not the machine
A builder who has only worked with excavators tends to think of clearance as a fixed offset from a machine. A crane or a concrete pump is different, because the highest point of the machine is not the highest point of the task. The boom tip, the hook block, the slings and the load itself all move through space, and the load moves further than the boom because it swings.
On a residential job the conductors in question are rarely the big transmission lines that make everyone cautious. They are the low-voltage service lines running from the street to the house, the lines crossing a rear boundary to a neighbour, and the communications cables strung at a similar height. These are the ones that get hit, because they look ordinary and because nobody plans a lift around them.
The practical consequence is that the exclusion zone has to be drawn around the space the load will occupy at every point in the lift, including the approach, the placement and the return. If the load passes under a line at any point, the line is in scope for the whole operation.
Planning a lift under or near overhead lines
- 1Identify the linesWalk the site and record every overhead conductor, including service lines to neighbouring properties and lines that cross the boundary.
- 2Confirm the voltage and required distanceAsk the network operator or check the current regulator guidance to establish the safe approach distance that applies to that line.
- 3Design the exclusion zoneConvert the distance into a marked zone on the ground that accounts for the full slew, boom reach and load swing.
- 4Choose the controlDe-energise, isolate, use a spotter, or re-sequence the work so no part of the plant or load enters the zone.
- 5Brief and verifyWalk the operator, rigger and spotter through the zone and the stop-work trigger before the first lift.
Establishing the safe approach distance for a particular line
The distance that applies on a given site is set by the voltage of the line and by the requirements of the network operator and the work health and safety regulator. It is not a single number that applies everywhere, and it is not something to carry over from the last job because the last job looked similar.
Before plant is mobilised, confirm the requirement from the current source: the network operator that owns the line, or the regulator guidance that applies in NSW. If you cannot establish the voltage, treat the line as the highest category until someone who owns the asset tells you otherwise. The cost of a phone call is nothing against the cost of a rebuild.
This is also where the principal contractor’s duty sits. Under the work health and safety framework, the person conducting the business or undertaking must manage risks to workers and others from electrical hazards, and overhead lines are explicitly part of that. Delegating the question to the crane company does not transfer the duty; it just means two parties are now exposed instead of one.
Controls in order of effectiveness
There is a clear hierarchy here, and it is worth being blunt about it. The controls that remove the hazard beat the controls that try to manage it in real time.
De-energise and isolate. The network operator can arrange for the line to be de-energised and isolated for the duration of the lift, with the isolation confirmed before work starts. This is the control that removes the hazard entirely, and it is available more often than builders assume, particularly where the work is planned far enough ahead.
Re-sequence or re-position. If the load can be brought in from a different direction, set down outside the zone, or placed before the line is strung, the risk disappears. On a renovation, this often means doing the lift before scaffolding goes up, or bringing material in from the street side rather than over the rear boundary.
Change the machine or the load. A smaller crane set up further away, or a load broken into pieces that can be handled without the boom entering the zone, may keep the whole operation clear.
Mark and fence the exclusion zone. Where the zone is physical, mark it on the ground and fence it so that no person, machine or stored material enters it. The zone must reflect the required distance from the line, not a convenient line on the ground.
Spotter and height limiting devices. These are the controls of last resort, and they only work where the operator and spotter have a clear line of sight to the conductor and a radio protocol that stops the lift immediately. They do not replace the planning above, and they fail in exactly the conditions — glare, wind, fatigue, a load that swings further than expected — where you need them most.
Lead in. The mistake that costs the most is treating the exclusion zone as a line on the ground rather than a volume in the air. A crane set up inside a marked zone because the boom was folded at the time is still a crane whose load will pass through the conductor on the way to the roof.
Marking the zone on the ground
The zone has to be legible from the cab and from the ground, and it has to survive a day of traffic. Paint on a driveway disappears under a wheelbarrow within an hour. Cones get moved. On a tight residential site the most reliable approach is to combine a physical barrier with a marked line that the operator can see from the seat, and to brief everyone on the site — not just the crane crew — that the zone is not a storage area.
Where the zone crosses a public footpath or road, the traffic management plan and the network operator’s requirements both apply, and the local council may need to be involved. This is a planning task, not a site task, and it belongs in the programme well before the crane is booked.
If the site is also being excavated for footings or services, remember that plant movement and spoil placement can push the working area closer to the line than the plan assumed. Our related article on plant, silica and asbestos in renovation work covers the plant selection side of that trade-off.
Controls for overhead line risk, ranked
| Higher-order control | Lower-order control |
|---|---|
| Have the network operator de-energise and isolate the line | Rely on a spotter to call a stop before contact |
| Re-sequence the work so the lift happens away from the line | Fit height limiters and hope the set-up matches the plan |
| Use a different machine or a smaller load that keeps the boom clear | Brief the operator to be careful and leave it there |
| Mark and fence the exclusion zone on the ground | Assume the operator can see the line from the cab |
| Confirm the distance in writing before plant arrives | Carry over a distance remembered from another site |
Working near service lines and communications cables
Service lines to the house and to neighbouring properties are the ones most often overlooked, because they are low, familiar and often assumed to be safe to touch. They are not. A service line is a live conductor, and the same approach distance logic applies to it as to any other overhead line, with the added complication that it may be attached to a structure the work is modifying.
Where a lift or a scaffold has to pass a service line, the options are to have the line temporarily disconnected by the network operator, to have it re-routed, or to design the work so that no part of the plant or load enters the zone. Scaffolders and roofers have the same exposure as crane crews, and the same planning should apply to the erection sequence.
Communications cables are a separate matter. They carry no supply voltage, but they are usually strung at a similar height and they are frequently attached to the same pole. Striking one still causes an outage, a repair bill and a complaint from the neighbour, and the strike often damages the supply conductor alongside it.
What a contact incident actually costs
The immediate cost of an overhead line contact is a person in hospital, and that is the only cost that matters in the first hour. The commercial consequences arrive later and last longer.
There is the network operator’s investigation, the interruption to supply for the street, and the repair or replacement of the conductor and any pole-top equipment. There is the regulator’s inquiry, which will look at what the principal contractor knew, what was documented, and whether the safe approach distance was established before the lift. There is the programme delay while the line is made safe and the incident is investigated, which on a residential job can push practical completion past a contract milestone.
Insurers will ask for the lift study, the exclusion zone marking, the briefing records and the correspondence with the network operator. If those documents do not exist, the position is difficult to defend even where the intent was reasonable. The paperwork is not the control, but it is the evidence that the control was planned.
Worked example: a lift over a rear boundary line
A builder in western Sydney is adding a first-floor extension to a rendered brick house. The roof trusses have to be craned over the house to the rear, and the only practical set-up position is on the street. The crane’s boom will pass over the front of the house, and the load will swing above the rear yard before being set down.
During the pre-start walk, the builder notices a low-voltage service line crossing the rear boundary from a pole in the neighbouring street to the house behind. It is at roughly the height of the proposed roof, and the swing path of the trusses passes under it.
The builder’s first instinct is to put a spotter on the boundary and instruct the crane crew to keep the load low. That is a lower-order control, and it depends on the load behaving exactly as predicted. Instead, the builder contacts the network operator, confirms the voltage and the required distance, and asks whether the line can be temporarily isolated for the lift window. The network operator agrees to a scheduled isolation, and the lift is programmed into that window.
In the meantime, the builder marks the exclusion zone on the ground for the days when the crane is on site but the line is live, fences it, and briefs the whole crew that no material is stored in the zone and no plant enters it. The truss lift goes ahead in the isolation window with the line confirmed de-energised. The cost is a scheduling change and a phone call; the alternative is a truss hanging in a live conductor above a neighbour’s yard.
Briefing the crew and the spotter
The briefing is where a plan either becomes a control or becomes a document. It needs to cover the location of every line in scope, the required distance, the marked zone, the stop-work trigger, and who has authority to stop the lift. That last point matters: a spotter who is not empowered to stop the job is a spectator.
Radio protocol should be agreed before the first lift, including the words that mean stop immediately and the words that mean hold position. The operator should confirm they can see the zone from the cab, and if they cannot, the set-up should change. On a residential site, the operator often cannot see the conductor above the boom head, which is precisely why the zone is marked on the ground and the spotter is positioned to see both the load and the line.
Weather belongs in the briefing. Wind moves the load, and heat affects the sag of the conductor, which changes the effective clearance. Guidance on managing work in hot conditions is published by Safe Work Australia, and the practical point for a lift plan is that the clearance confirmed in the morning may not be the clearance at the end of a hot afternoon. If the lift is marginal, do it early or reschedule it.
Where this fits in your CPD and your systems
Overhead line management sits inside the broader electrical safety and plant safety competencies that NSW licensed builders are expected to maintain. If you are mapping your CPD year, the guide to how NSW builder CPD works sets out the categories and the record-keeping expectations, and the PointCPD course catalogue lists the safety and plant courses that cover this ground in more detail.
The site-side system is simpler than the CPD side. Add a line to your pre-start checklist that asks, for every job involving a crane, concrete pump, scaffold or elevated work platform: what overhead lines are in scope, what is the required distance, how is the zone marked, and what is the control if the load enters it. That single question, asked before plant is booked, catches most of the incidents that would otherwise be planned around afterwards.
If you are not sure of the distance that applies to a particular line, stop and confirm it with the network operator or the current regulator guidance before the machine arrives. The requirement is specific to the line, and it changes. Getting it right is a planning task; getting it wrong is an incident.
Frequently asked questions
These are the questions builders raise most often when a lift is close to a line. The answers are general — the specific distance for your site must come from the network operator or the current regulator guidance.
Questions builders ask
What is a safe approach distance for powerlines?
It is the closest any part of the plant, the load or its rigging may come to an overhead line, and it applies to the whole swept path of the lift rather than to the machine’s resting position. The actual distance depends on the voltage of the line and on the requirements of the network operator and the regulator. Confirm it from the current source for the specific line before plant arrives.
Do I need a spotter every time a crane works near overhead lines?
A spotter is a lower-order control and should not be the primary measure. Where the line can be de-energised and isolated by the network operator, or the work re-sequenced so the load never enters the zone, that is the better answer. A spotter is appropriate only where a higher-order control is not practicable, and only with a clear line of sight and an agreed stop protocol.
Can I just keep the load low and pass under the line?
Keeping the load low reduces the risk but does not remove it, because the boom tip, hook block and rigging are still in the air and the load can swing upward or sideways. The distance that matters is measured from the conductor to the closest part of the whole system, not to the bottom of the load. If any part of the plant or load enters the zone, the control is not adequate.
Who is responsible for identifying overhead lines on a residential site?
The principal contractor holds the duty to manage the risk to workers and others from electrical hazards, which includes overhead lines. That does not transfer to the crane company by delegation. In practice the identification should happen during planning, well before plant is mobilised, and it should cover service lines to the house and to neighbouring properties as well as the obvious street conductors.
What do I do if I cannot find out the voltage of a line?
Treat it as the highest risk category until the network operator tells you otherwise, and plan the exclusion zone accordingly. Do not assume a line is low voltage because it is low to the ground or because it looks like a communications cable. Confirm the asset owner and the required distance in writing before the lift is scheduled.
Does heat affect overhead line clearances?
Yes. Conductors sag as they heat up, so the clearance measured in the cool of the morning may be less by the afternoon. Wind also moves the load and changes the swing path. If a lift is marginal against the required distance, schedule it for the cooler part of the day or reschedule it, and include the conditions in the pre-lift briefing.
Sources
- Electrical safety · Safe Work Australia
- Working in heat · Safe Work Australia
- Cranes · Safe Work Australia
- Excavation · Safe Work Australia
Published 9 September 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.
