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TREES AND POWERLINES

Trees near powerlines can be dangerous and in stormy conditions will often cause interruptions to the power supply. Falling branches can break lines causing fire and the risk of electrocution. Trees touching powerlines can cause damage to the Network, power failures and in some cases even death.

Why are we telling you this?
Because, it is as much your responsibility as it is ours to keep trees away from powerlines.

What are your Tree-sponsibilities?
You are responsible for organising regular maintenance (tree trimming) if you own a tree that is near powerlines. The tree is yours if you own the land the tree is on. Click here for more information

What distance do trees need to be from powerlines to be legal and electrically safe?
The Electricity (Tree) Regulations 2003 provide specific distances for which trees must be kept away from power lines. The distance is dependant on the line voltage, and is referred to as the Growth Limit Zones.

The Growth Limit Zone is the space surrounding any powerline that must be kept clear of trees. The size of this zone depends on the voltage of the power lines. Trees that are in the Growth Limit Zone must be pruned back outside the Notice Zone. This work must be done by electrically competent tree workers, authorised by Northpower to do so. The Notice Zone extends 1 metre beyond the Growth Limit Zone. In some cases trees in the Notice Zone can be pruned by tree owners, provided they have written consent from Northpower.

The following table shows the clearances needed for the power lines that have a span of up to 150 metres.

GROWTH LIMIT ZONE
VOLTAGE	GROWTH LIMIT ZONE (Distance in any direction from any point on the lines or equipment)
33kV	2.5m
11kV	1.6m (most common)
400/230V	0.5m

Tree owners who fail to comply with the ‘Tree Regulations’ could be fined up to $10,000 plus up to $500 a day for a continuing offence. Tree owners could also be liable for costs if Northpower lines or equipment are damaged by their tree(s).

For a downloadable pdf version of this information, click here.