If you're designing or installing low voltage reticulation in the Northpower network area, here's some information you may find useful.
This information is for connections within the Northpower network area for residential, commercial and rural locations.
This information is specific to the Northpower network area, so if you're connecting to another network please get in touch with them.
Underground reticulation shall be designed so that two phases are available at the boundary of each lot, including those serviced by spur cables along access ways and rights-of-way. In general, reticulation will be three phase with one fuse per lot at the pillar services, plus allowance for a second fuse to be fitted only when required.
In underground areas, construction plans shall show the phase allocated for the first connection and the phase for the second if required.
The load shall be balanced across the three phases by connecting service lines to sequential phases. The developer may request the reticulation to be designed to a higher capacity.
The service to a 'standard' dwelling will generally be single phase except where there is a long service line and an additional phase is required to reduce the voltage drop. Large dwellings (load in terms of electrical load) will generally be two phases.
When individual consumers request greater capacity, diversity of the original design low voltage network can be considered. The low voltage cut out is generally 60/63A unless otherwise specified.
When designing a low voltage network for a commercial subdivision or development, Northpower requires each lot to have a three phase 60A supply available.
In many situations Northpower stipulates additional requirements which are based around growth to minimise disruption to adjacent landowners in future,
e.g. installation of extra ducts.
The electrical requirements for urban or heavy industrial can be tailored to meet the requirements of the developer and Northpower.
In the case of multiple lots supplied from one transformer, three phases should be available to each lot.
The most common exemption is where the 11,000 volt network is is two wire.
The service will generally be two or three phase, as required to ensure the voltage drop is within regulatory limits and load balance on the transformer.
In the case of a single lot or dwelling, the supply available will be three phase if a three phase transformer is provided and the service should also be three phase to ensure the transformer load is balanced.
If a single phase 460V transformer is provided, the supply available will generally be two phase.
The service will generally be two phase, but single phase can be accommodated by paralleling the output of the two secondary windings of the transformer.
The low voltage cut out is generally 30/32A, 60/63A depending on the situation.
Generally the supply will be three phase for most situations, e.g. dairy shed, large pumps etc.
Extra light industrial installations can be two or single phase if required. 'Extra light' generally refers to small pumps and implement sheds with minimum electrical load.
The low voltage cut out will be sized to suit the situation.