Ausgrid trims trees around the electricity network to keep the community and our staff safe and to help make sure we are providing a reliable electricity supply to our customers. Removing branches from around powerlines and power poles helps prevent blackouts, bushfires and accidental electrocution.
We know that trimming large trees planted under powerlines can look harsh and while trimmers try to balance the amenity of local street trees, we have a responsibility to keep the network and the power supply to our customers’ homes and businesses safe.
The safety clearance distances are determined by statewide industry guidelines. The amount trimmed depends on the species of tree, the type of powerlines or poles, and whether it’s in a bushfire prone area.
Generally, in residential areas the clearance around bare low voltage powerlines is 1 metre. Once crews have cleared to the minimum clearance distance, they provide an allowance for regrowth so the branches won’t enter the clearance distances before the next annual visit. To protect the health of the tree, the branches are then trimmed at their nearest growth point or collar. This protects the tree from infection and disease and is in line with the Australian Standard for amenity pruning AS4373.
Trimming is carried out by contractors trained to work in close proximity to the electricity network. In addition Ausgrid and the contractors each employ a horticulturalist and arborist to inspect the trimming work, ensuring it is all done to standard and the trees remain healthy.
It is very important that you do not attempt to trim trees near powerlines. If you have trees on your property that are growing near powerlines, make sure you engage a qualified contractor.
Avoiding planting large trees near powerlines is the best way to protect your local electricity supply and minimise the need for trimming. Learn more about suitable and unsuitable species.
When assessing the options available, there are a few things that need consideration, including cost. Keeping the existing overhead powerlines and trimming the trees around them is the most economic option for the community, ie it is free to residents and councils.
In some areas Aerial Bundled Cable (ABC) has been installed, usually at the request and cost of the local council. ABC wraps the four low voltage wires, into one insulated cable. This insulation reduces the likelihood of a power interruption, caused by branches coming into contact with the lines an creating a short circuit. Replacing bare low voltage powerlines with ABC, reduces the clearances for trimming, but it is likely that some sort of trimming will still be required. Installing ABC is usually funded by local councils or the resident who requests it.
Powerlines or cables are also placed underground in some areas, like all new urban residential developments and some commercial areas. While this removes the need to trim any tree branches, underground cables can still be affected by roots, so it remains important to think about what sorts of vegetation is being planted and what may lay beneath the ground.
Undergrounding electricity cables is the most expensive option. Costs vary depending on a range of technical and environment factors and Ausgrid considers all requests for undergrounding on a case by case basis in accordance with the "Network Undergrounding Policy Guidelines”. Like installing ABC, undergrounding is usually funded by the beneficiary.