Trees & power lines

Trees account for approximately 25% of our unplanned network outages each year. This can be from fallen trees, branches, bark and other debris on power lines.

Rules and regulations

As property owners and tree growers, there are regulations in place to ensure power lines are kept clear of trees and risks are minimised.

Tree safety notices

Under the Electricity (Hazards From Trees) Regulations 2003, we are required to issue notices to tree owners if we identify the vegetation growing within the set distances.

Be aware of tree growth

How far apart should they be?

The Electricity (Hazards From Trees) Regulations 2003 define two zones:

  1. A Growth Limit Zone; and
  2. A Notice Zone (shown in the diagram).

Growth limit zone

This is the area within 1.6 metres in any direction of our 11,000V electrical conductors or 0.5 metres for 400/230V electrical conductors. If any of your tree foliage is within this zone, it must be trimmed beyond the notice zone.

Notice zone

This is the area one metre in all directions around the growth limit zone. If we know about trees growing in this zone, we may issue you a Hazard Warning Notice to inform you that the tree must not be allowed to grow into the growth limit zone.

Service Mains

A service main connects your property to our network. This typically forms an overhead or underground connection from the street pole to your house.

Waipā Networks does not own this and is not covered by the regulations. You must keep trees clear of this line.

If you need to carry out a trim, Waipā Networks can temporarily disconnect the power. See the safety disconnection page for more information.

Safety disconnections are free if it is no longer than 15 minutes during business hours (a charge applies for 11 kv lines in all cases).


Meeting the tree regulations

As a tree owner, you may receive a Trim Notice regarding a tree on your property. It is essential to promptly adhere to the regulations outlined in this notice, as failure to do so may result in committing an offence.

  • Fail, without reasonable excuse, to cause the tree to be cut or trimmed per the Regulations; or
  • Fail, without reasonable excuse, to advise Waipā Networks of the time and location of the tree’s cutting or trimming.

The fine for this is $10,000 and $500 each or part day during which the offence has continued.


Keeping you safe around trees near power  

  • Trees growing close to power lines and other electrical conductors pose a severe risk to public safety.
  • They may also cause power cuts or voltage problems for connected consumers.
  • If a tree encounters a live electrical conductor, the current may travel through the tree and into the ground.
  • Anyone touching or close to the tree could suffer a severe electric shock.
  • Those at highest risk are people carrying out tree maintenance or children playing in or around a tree, both of whom can cause branches to move and encounter the lines.

Tree trimming – the dangers 

Limit Zone (see diagram) must only be trimmed by a Waipā Networks authorised person. 

Before clearing tree foliage near live conductors, ask Waipā Networks for advice.
Growth Limit Zone: Any tree growing in the Growth Zone.

Branch Movement:  

Although the tree foliage may appear safely from the lines, once you begin the work, the tree may move due to pressure placed on branches, random wind gusts, or other external interference. 

Things to remember: Tree branches tend to be elastic, so you should also be wary of any that may flick up as they are trimmed or as other surrounding branches are cleared. 

Wet Weather:  

Branches tend to hang lower when the leaves are wet, so you should expect some movement if it starts to rain or if the leaves are already wet and start to dry. 


The path of debris should also be considered when attempting tree maintenance. 

These and other dangers mean we strongly recommend you refrain from trying the work yourself. 

Leave tree trimming to the professionals

Waikato Tree Services

Waikato Tree Services have cared for trees in Hamilton and surrounding areas for almost 30 years. Since taking ownership in 2010, Waipā Networks Ltd has grown the company to include three teams of fully qualified and experienced arborists, with a fleet of modern, hi-tech equipment, including an 18.5-metre high cherry-picker. You can contact them for any sized job!

Website waikatotrees.co.nz

Email: trees@waikatotrees.co.nz

Tel: 0508 87 33 22

These photos represent severe weather’s impact on trees and power lines in the Waipā region. Extreme weather conditions highlight the importance of maintaining your trees as it reduces potential damage to power lines.