Solar connections
Single line diagram
A single line diagram (SLD) 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.).
SLDs must use correct electrical symbols and 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
- show site main switch is a circuit breaker rated to the sites supply allocation (or will be at time of installation)
- any private/customer smart meters
- distribution boards
- loads
- all inverters – new and existing
- energy source (PV array, batteries, etc.)
- any communications and controls/monitoring equipment*
- protective devices
- cable size and length between all the above
- description of the working/operational philosophy of the proposed system
* Where monitoring equipment is required for site generation limiting or self-consumption control, the following need to be indicated in the SLD:
- monitoring equipment such as Current Transformers (CT) or energy meters
- the phase/s that the equipment is monitoring
- any links between the monitoring device and the battery storage device (refer to sections 2.1 of the Battery Inverter Energy System (IES) Requirements for more details)
Electrical symbols - AS/NZS 3000:2018
| Switch (general symbol) | Transformer (single line) | ||
| Mechanically interlocked changeover switch | Switch disconnector (on-load isolating switch) | ||
| Disconnector (isolator) | Fuse | ||
| Alternator | Circuit breaker | ||
| Circuit breaker, earth leakage type, current operated (RCD) | PV array | ||
| Battery | Inverter | ||
| 3 pin socket outlet or cord extension socket |
Protective earth neutral (PEN) conductor
|
||
| 3 pin socket inlet or plug | Neutral conductor (N) | ||
| Protective earthing conductor (PE) | Connection to earth | ||
| Generation frame connection | Earth or neutral bar | ||
| Whole current (direct connecter)meter (non CT) |
|
LV current transformer meter (LV CT) | |
| HV current transformer metering unit (HV CT) |
Connection block | ||
| Combination fuse switch | LV links or HV/LV load disconnector | ||
| Drop out fuse (DOF) | Generator |
Site diagram
Identify on an aerial site diagram e.g. Landgate property search photo:
- supply type (overhead or underground)
- property/lot boundaries
- point of supply for the private installation:
- if underground, Western Power pillar/dome
- if overhead, mains connection box (typically next to point of attachment) or
- Western Power distribution substation e.g. transformer kiosk (strata and larger commercial)
- if overhead supply, the Western Power service cable run from the network to point of attachment
- transformer in rural or sole use cases
- Western Power meter
Examples of site diagrams
Date effective: 14 February 2022
The terms used in these conditions have the same meaning as in the Western Australian Service and Installation Requirements 2021.
1. Approval is void should the application details be subsequently found to be invalid.
2. The approved system must:
- not be connected after the expiry date recorded on the approval
- be connected via a Western Power approved import/export meter
- be installed as detailed in the approved application (including diagrams) and, if special operating
conditions are applied, to comply with the conditions before commissioning - have switches/breakers installed to legislative and network operator requirements
- be designed for a maximum voltage rise within the installation of less than 2% or 4.8 V as per
AS/NZS 4777.1:2016 - use CEC approved products with compliance to extra requirements of volt-watt, volt-var,
IEC 62116, VDRT (new equipment) - comply with Western Power’s Basic and LV EG Connection Technical Requirements
3. All electrical installation, commissioning and maintenance work wherever required must be carried
out by an electrical contractor licensed under the Electricity (Licensing) Regulations, 1991.
4. Western Power may inspect the installation from time to time to ensure continued compliance with
these requirements. If we consider that the installation poses a threat to safety, to quality of supply,
to the integrity of the distribution system or does not conform with Western Power technical
requirements we may disconnect the equipment.
Your connection point has a fixed capacity. If it is shared with other customers, potentially multiple new systems could be added and exceed that capacity. This can make it unsafe and unreliable.
Shared connections must be managed to ensure that all customers have access to a safe and secure electricity supply as well as the opportunity to connect to benefit from renewable energy solutions.
Before applying to connect this type of equipment, tenants or owners with shared connections should first seek permission from their strata company or management body to use a portion of the total network capacity allocated.
Failing to do this may prevent others from connecting their equipment, or require the management body to upgrade the connection to our network to accommodate the needs of all owners and or tenants.
It's important to remember that the strata company or management body is ultimately responsible for the management of the common connection to the network and the common electrical system. Effective management of this shared resource will allow the benefits of renewable energy solutions to be shared by all.
More information about strata titling principles can be found in Landgate's Guide to strata titles.
Shopping centres, commercial tenancies, strata schemes and other grouped properties typically share a single connection point to our network that determines the total allocation of available electricity supply and generation capacity to be shared by all lots.
This connection point has a fixed capacity, so it's important for tenants, owners and prospective purchasers to be aware of the arrangements and obligations relating to the connection, as it may restrict their ability to install equipment such as home EV charging stations, rooftop solar panels and batteries.
The revenue meter is required to be changed or reconfigured to measure bi-directional energy flows (import – export meter registers) before the connection of the embedded generation system. Please contact your electricity retailer before applying to Western Power for technical approval of your proposed system.
If a sub-meter is associated with the connection point at which bi-directional flows will occur, you may wish to engage a licensed electrical contractor to change the sub-meter and make the necessary arrangements with you at the revenue meter.
If bi-directional flows will occur at a sub-meter the measurement of energy flows is at the discretion of the customer. You may wish to engage an electrical consultant or contractor for energy management options.
Common sub-metering arrangement
The diagrams below illustrate typical revenue meter and sub-meter configurations.
Residential property with granny flat
Apartment buildings and shopping centres
Power station
Note: SPD means Service Protection Device.
Your connection will either be an individual connection or a shared connection.
Each connection has a ‘generation allocation’, or amount of solar, it can accommodate.
When you make an application to us to connect solar PVs our system will show whether the connection for the given address is individual, shared or unknown. The connection type is important to us for assessing the application.
- Individual connections have their own connection and generation allocation.
- Shared connections share a connection and generation allocation with others in the same development.
- Unknown means we must review to resolve which connection type it is.
These diagrams illustrate common connection types.
Individual connections
Individual underground connection
Individual connection with an overhead service cable
Individual connection with an overhead service cable and customer poles
Shared connections
Units in developments such as strata schemes, shopping centres and residential parks connect through a switchboard to the grid.
Sometimes in small older developments, units connect directly to the connection point. However, all units still share the generation allocation.
Shared underground connection
Shared connection with an overhead service cable
You need Western Power approval if:
You are installing a new solar system, or relocating an existing solar system, or changing or upgrading an existing system or replacing an inverter.
But if you are doing like-for-like maintenance work or only changing PV* panels, then no application is required.
Like-for-like maintenance work means it has the same maximum power rating, same phase, same quantity and/or has a Western Power approved battery (current CEC approval and volt var, volt watt, IEC 62116).
For all other work you will need to apply via our application page.
Please note - if you have a three phase connection and are replacing a single phase inverter with one greater than 3kVA, you now need to apply for approval. This is because, the new inverter will not operate at optimal efficiency.
*PV stands for Photovoltaics otherwise known as solar panels
Stratas, lifestyle villages and other multi-residential sites usually share a single connection to the grid. These properties can have tens or even hundreds of homes behind a 'shared connection', which means that the combined total of installed solar generation can easily pass the 30kVA limit. Above this limit an installation needs to comply with more complex connection requirements and higher costs associated with the larger (above 30kVA) application.
To allow residents of such sites to take advantage of solar power an exemption is available to the land-owners or their representative e.g. the strata management company, of multi-residential sites to allow these sites to contain up to 500kVA of generation without incurring the fees associated with a larger application.
This exemption is applied for by the land-owners of the site or their representative.
How this may affect your application:
- If it's predicted that the site will exceed 30kVA of aggregated embedded generation, the land-owners of the site or their representative should apply for a Multi-residential exemption as soon as possible
- Once the site has exceeded 30kVA, the technical exemption will be required before any further solar applications can be processed and you may need to quote the exemption identification number during your solar application
- An approved exemption will describe a maximum amount of solar that can be installed at a site, how this allowance is shared among residents of the site is the responsibility of the land owners or their representative – you will need to check with them before applying
- Within the exemption, individual homes can have up to 5kVA of generation but the land-owners or their representative may advise that a lower limit needs to apply
Multi residential land-owners
- Further technical information is available on the Multi-residential exemption application form
- This application requires the certification of a suitably qualified registered electrical engineer.
Find an engineer via the National Engineers Register or contact Engineers Australia for more information.
See also: Do I need permission from my strata company before applying for my connection?
Residential applications can only be approved up to 30kVA.
In small strata situations – where 2-4 homes can sit behind a single connection - it is possible that your neighbours have already installed enough generation that the amount you requested is not available. You will need to apply for a system with a limit that works within the remaining amount.
In larger stratas: lifestyle villages or residential developments, the land owners of the multi-residential site or their representative e.g. the Strata management company may need to apply for an exemption to allow residents to connect solar systems. You will need to talk your property manager to move forward with your plans.
No. This is not a service that Western Power offers. If you are thinking about getting solar panels installed refer to our article what to look for in a reliable solar installer in Perth
If you have installed a different inverter make and model to that shown in the EG Preliminary Approval to Connect, you can update the inverter details in the EG Registration form.
- Step 1 - Go to ‘Update Inverter Details’ and follow the prompts to enter the information of the installed inverter.
- Step 2 – Go to ‘Enter Serial Number(s) and enter the Serial Number of the installed inverter
All inverter brands display a unique serial number format. This format is a combination of alphanumeric numbers and characters of varying lengths and structure.
The Serial Number field validates to the exact format associated with the selected inverter.
Below are examples of the correction formatting
Example #1
If you have installed a Fronius inverter then the serial number format must be a total of eight numeric characters and the first number must be a "2" or "3". For example: 21234567
Example #2
If you installed a Growatt inverter, the first three characters must be alphabetic, followed by seven alphanumeric characters. For example: ABC123456A