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How the National Environmental Standards deal with electricity transmission activities (7 of 12)

These pages set out aspects of the NES that Transpower and councils need to consider for transmission activities.

  1. Summary of the NES
  2. Operation of existing transmission line and use of access tracks
  3. Overhead conductors and adding overhead circuits
  4. Earthwires and telecommunications cables
  5. Work on underground conductors / Taking existing overhead transmission lines underground
  6. Increasing voltage or current rating / Electric and magnetic fields
  7. Transmission line support structures — alteration, relocation, and replacement / Temporary / Removal
  8. Telecommunications and signs / Devices / Signs
  9. Discharges
  10. Trimming, felling, and removing trees and vegetation
  11. Earthworks
  12. Noise and vibration from construction activity

Transmission line support structures — alteration, relocation, and replacement

Definitions of support structure and tower height

By definition, support structures include associated hardware such as (but not limited to) insulators, cross arms or guy wires. The definition also includes the structure's foundations - see Existing lines. Any changes to the associated hardware will come within the NES provisions that address changes to transmission line support structures.

The NES defines tower height. Any earthpeaks or lighting rods are not included in the tower height, even though they are within the definition of 'support structure'. There are separate regulations covering telecommunications devices, and these are not part of the tower nor included in the tower height.

See examples of Existing lines and further information on activities carried out on support structures:

  • foundation types and associated earthworks
  • tower / pole strengthening
  • relocation / replacement.

Explanation: work on transmission support structures permitted

Work on transmission support structures that meet the conditions in regulation 14 is permitted. The regulation set out limits for altering and moving support structures to limit the effects.

The NES also defines a 'footprint' for the tower, and a base footprint, which is the footprint at 14 January 2010.  For movement of towers, the NES defines an envelope for permitted activities, and an envelope for controlled activities.  These envelopes are based on the tower footprint - refer to diagrams in the regulations.

The NES uses the base height, base footprint and envelopes to limit the distances that towers can be moved (or the footprint increased) or increased in height as permitted or controlled activities.

This regulation includes provisions which permit:

  • increasing the height of any support structure by up to 15% of the base height, provided the additional height complies with any restriction for airports or public view shafts specified in a rule – regulation 14(3)
  • altering and strengthening towers and associated hardware, as long as the alteration meets the height limits and footprint limits – regulation 14(3) and (5)
  • moving a tower within a defined 'permitted activities envelope' – regulation 14(6); or a pole within 5 metres of its original position – regulation (14(3) as long as it is not moved to
    • within 12 metres of an occupied building, or
    • any closer to an occupied building, if the tower is already within 12 metres.

However:

  • If the limits on moving support structures are not met, the activity is:
    • controlled, if the movement is within the distances specified for controlled activities - regulation 15 - or
    • restricted discretionary, if it is moved beyond the controlled distances or within 12 metres of an occupied building (or any closer to a building if it is already located within 12 metres) – regulation 16.
  • A pole cannot be replaced with a tower: this is restricted discretionary – regulation 16(2)(a).

Explanation: alteration and relocation of support structures restricted discretionary

If towers and poles are moved or altered in a way that does not meet the permitted or controlled activity conditions, the activity is restricted discretionary - regulation 16. The EMF conditions in regulation 10(2) to (8) must be complied with (except for termination structures as part of undergrounding or when part of a temporary line deviation).

The local authority has discretion to take account of any of the following matters in determining whether to grant the consent, and in setting conditions:

  • the location and height of the transmission line support structure in relation to:
    • visual, landscape and ecological effects
    • the effects on historic heritage
    • the effects on sensitive land uses
  • earthworks, clearance of trees and vegetation, and restoration of land
  • effects and timing of construction works.

Associated activities that may need consent

Work on transmission line support structures may require ancillary work and result in associated effects, such as tracking to access the lines, earthworks to create platforms for equipment, noise generated from the use of machinery or vegetation clearance. Tower relocation and maintenance works may be done in conjunction with other tower maintenance (eg, cleaning, painting and foundation works). As such, consents may be needed for some of these activities.  A project involving tower maintenance or relocation could also involve work on conductors.

To work out other consents that may be needed for a project see

Refer to regulation 14, regulation 15 and regulation 16.

Temporary structures and temporary line deviation

Refer to technical information on temporary structures and line deviation.

Explanation: temporary structures and temporary line deviation

Temporary structures are a permitted activity, provided they are put up no more than 20 working days before the start of the project and removed within 20 working days after the completion of the project. A temporary structure may include hurdles and nets that are required for safety purposes, and lighting structures to facilitate night work - regulation 17.

If the structures are part of a temporary line deviation this is also permitted, and the structures must be put up no earlier than 60 working days before the start of the project and removed no later than 60 working days after the end of the project - regulation 17.

Temporary is not defined in the NES, so it takes its ordinary meaning: "lasting for only a limited period" (Concise Oxford English Dictionary 11th edition).

If the temporary structure or temporary line deviation does not meet the permitted activity conditions, it will be treated as a controlled activity - regulation 18. Control is reserved over:

  • the duration of any works
  • the effects and timing of construction works.

Transmission lines — removal

Explanation: removal of transmission lines

If a section of transmission line is no longer required it may be removed, either completely or partly. This may include removal of the conductors and/or transmission line support structures.  In many cases, it may be less damaging to leave tower foundations in place rather than undertake extensive earthworks to remove them. These activities are permitted, provided that the demolition material is removed and the land is restored - regulation 19. In the unlikely event that these conditions cannot be complied with, the activity is controlled - regulation 20. Control is reserved over:

  • earthworks, clearance of trees and vegetation
  • restoration of the land
  • the effects and timing of construction works.

 

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Last updated: 18 January 2010