National Environmental Standards for Electricity Transmission Activities: definitions

Many terms used in the NES have specific meanings and are defined in the NES.

Unless defined in the NES, any definitions of terms in the Resource Management Act 1991 apply where these terms are used in the NES.

Such definitions may differ from the common use of the word or phrase.

Examples:

'natural area' has a specific meaning in the NES – it "means an area that is protected by a rule because it has outstanding natural features or landscapes, significant indigenous vegetation, or significant habitats of indigenous fauna".
the 'height' of a transmission support structure as defined in the NES does not include any "devices, earth peaks, and lightning rods".
'plan' is defined in the RMA as "a regional plan or a district plan", and these terms are also defined in the RMA.
'termination structures' as defined inthe NES is "a tower or pole used for the transition between an overhead and an underground transmission line". (Engineers generally refer to these as 'transition structures'.)

It may not be obvious that a word or phrase has a specific legal meaning, so if in doubt you should check the definitions.

For terms defined in the NES, refer to Interpretation, clause 3.
For terms defined in the RMA, refer to Interpretation, clause 2, to clause 43AA and to clause 43AAB.

Additional terms

amps: When electricity flows (like water passing through a hose), there is said to be an electric current. The current is measured in amperes or amps (A).
maintenance: The process of maintaining or the state of being maintained; to maintain - keep in good condition by checking or repairing regularly (Concise Oxford English Dictionary, 11th Edition).
outage: The period during which a line is taken out of service. Outages are carefully planned to avoid loss of supply to electricity users.
thermal limit: Limit to the amount of power that can be sent over a transmission line. Heating of the conductor causes it to expand, thereby increasing its length and sag. So the position of a conductor above the ground will rise and fall depending on the current, but is also influenced by the ambient conditions such as temperature and wind speed. If too much current is allowed to flow, the conductors may sag too close to the ground.
temporary: Lasting for only a limited period (Concise Oxford English Dictionary, 11th Edition).
voltage: Electricity is rather like the flow of water through a hose. In the same way that there is pressure in a hose (even if the water is not flowing), there is an electrical pressure: this is known as the voltage in a transmission line. It is measured in vols (V) or kilovolts (kV = 1000 V).

Last updated: 2 June 2010