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What do I need to know about technical diagrams for inverter energy systems?

Single line diagram

A single line diagram needs to contain information on the installation wiring from the point of supply off the Western Power network, through to all the inverters on site, including where the customer’s load is connected. 

It also needs to contain information on all protection devices and switches, as well as any communications required to achieve the desired operation of the system (i.e. self-consumption, export limit, etc.).

All diagrams should contain at least, but not limited to, the following information specific to the site in question:

  • point of supply off the Western Power network
  • Western Power meter
  • any private smart meters (where used)
  • distribution boards
  • load
  • all inverters – new and existing
  • energy source (PV array, batteries, etc.)
  • communications and controls (where used)
  • protective devices
  • cable size and length between all the above

Site diagram

Identify on an aerial site diagram e.g. Landgate property search photo:

  • supply type (overhead or underground)
  • property boundaries
  • if overhead supply, then the Western Power service cable run from the network to point of attachment
  • point of supply for the private installation:
    • If underground, Western Power pillar (residential and some commercial)
    • If overhead, mains connection box (typically next to point of attachment) or
    • Western Power distribution substation e.g. transformer kiosk (strata and larger commercial)
  • transformer in rural or sole use cases
  • Western Power meter

This information allows our assessor to confirm the site and determine the voltage rise for your proposed system. If we don't receive this information, we won't be able to process the application.

Examples of cable diagrams

Example site diagram

Example site diagram

Example site diagram

 Example site diagram



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