Basic Embedded Generator Connection Technical Requirements
The Basic Embedded Generator (EG) Connection Technical Requirements set out the technical standards for connecting basic embedded generation systems - such as small-scale solar and other Distributed Energy Resources (DER) - to Western Power’s low voltage (LV) distribution network. They explain what customers, installers and service providers must do to safely connect and interface with our network.
The current requirements apply to all basic embedded generator installations across Western Power’s network. These requirements must continue to be used for all applicable connections until further notice.
By applying consistent technical standards, Western Power helps ensure DER systems are connected safely, operate reliably, and provide equitable access to the network—supporting community confidence, network stability and fair outcomes for all users.
Supporting information
FAQs
Meeting the Technical Requirements:
- protects people, property and the network from electric-shock, fire and equipment damage
- maintains voltage, frequency and power-quality standards as more solar and batteries connect
- ensures fair allocation of network capacity, enabling consistent, efficient assessment and approval for all customers
FAQs for inverter capacity
We’ve lifted the allowable single-phase inverter size from 5kVA to 10kVA to better support WA’s energy transition. The change, set out in the updated Basic Embedded Generator (EG) Connection Technical Requirements, helps customers:
- use more of their own renewable energy
- lower energy costs
- earn higher returns when joining Virtual Power Plants (VPPs)
- accelerate network decarbonisation
- electrify homes (EV charging, batteries, electric appliances) with confidence
Keeping the 5kVA limit on a three-phase supply reflects our commitment to safety, reliability and fairness:
- Service capacity – A 10kVA single-phase inverters nominal current rating is 40A; each phase of a standard three-phase service is rated at 32A. Overload is possible.
- Phase imbalance & neutral voltage rise – Large single-phase inverters on a three-phase service can raise neutral voltage and increase electric-shock risk.
- Neutral conductor heating – Large unbalanced current can overheat the neutral (typically 6 mm² consumer mains), shortening equipment life and creating a fire hazard.
An electrician should inspect any three-phase site before installing single-phase generation.
Yes, if it is generation-limited to 5kW. Limiting output reduces:
- neutral voltage rise
- thermal stress on the neutral and phase conductors
- risk of overloading a 32A phase conductor
- Single-phase: 63A (~15kVA)
- Three-phase: 32A per phase (~24kVA total)
FAQs for generation limiting
Generation limiting constrains one inverter (or a group of inverters) to a set maximum output (for example, 5kW) even though the hardware could deliver more. Settings must meet the Basic EG Connection Technical Requirements.
Follow AS/NZS 4777.1 Appendix C phase-balancing rules:
Install 5kVA Single-Phase Inverters on Different Phases:
- You may install up to 5kVA single-phase inverters on each of the three phases. This method ensures natural phase balancing, as each phase carries an equal share of the generation load and if one inverter generates less the imbalance is still less than 21.7 A. Each inverter should have the same generation type connected.
Install Multiple Single-Phase Inverters on Different Phases with Phase Balance Protection:
- If you wish to install multiple single-phase inverters (>5kVA) they need to be distributed on each phase equally, you must implement AS/NZS 4777.1 phase balance protection (i.e., limit of 21.7A between any two phases). This protection ensures that the total generation across all three phases remains balanced, preventing issues such as neutral voltage rise and thermal overload of the neutral conductor. If they are >8 kVA, then inverter generation limit of 8 kW needs to be set.
Install Larger Single-Phase Inverters (e.g., 10kVA) with Generation Limiting to 5kW:
- A larger single-phase inverter (up to 10kVA) may be installed on a three-phase connection only if it is generation-limited to 5kW. This limit helps mitigate phase imbalance risks.
Yes, the Basic EG Connection Technical Requirements allows the installation of multiple combinations of inverters installed at the same site. However, it is the responsibility of the electrical contractor undertaking the installation to ensure that the customer’s electrical installation behind the network connection point is appropriately rated and meets the requirement of WAER, AS/NZS 3000 and AS/NZS 4777.1.
The Basic EG Connection Technical Requirements supports multiple inverter installations up to the Site Generation limit as per Tables 4.1, 4.2 and 4.3. Where the aggregated rating of all installed inverters exceeds the applicable Site Generation limit, then Site Generation limiting needs to be applied in accordance with the limits and the functionality of AS/NZS 4777.2. For three-phase connections additional phase balancing is required.
The requirements apply to combinations of single energy source inverters without battery systems and battery system inverters that are ac coupled or dc coupled.
No, the updated Basic EG CTR allows a site generation limit of up to 8kW per phase for a three-phase connection service as per Tables 4.1. However, in this instance on the phase the AC coupled battery is installed the per phase Site Generation Limit is exceeded, this phase with the single-phase inverter will need to be generation limited to the per phase generation limit.
No, phase balancing requirements are not required for installations involving three-phase inverters as it is assumed that the output of generation is balanced across all phases.
No, the maximum inverter limit for inverters on large networks is 15kVA. A 30kVA inverter may be used but will need to be limited to 15kW.
Yes, where the aggregate of name plate rating of all inverters proposed exceeds 30kVA they need to be assessed by a Western Power technical specialist and a connection application will need to be submitted through a non-standard connection process which will include fees for the connection assessment.
No. Existing approvals were assessed under the rules in force at the time. Any modification – including altering export or generation limits, or addition of new equipment, triggers a new application, and the whole site must meet current Basic EG Connection Technical Requirements.
FAQs for export limits
Export limits are applied nett at the network connection point. Export limits do not apply at the inverter or per phase level.
For example, for a single-phase Standard Connection Service the total export contributed by all the installed single-phase inverters must not exceed the Export limit values as per Tables 4.1, 4.2 and 4.3. For a three-phase Standard Connection Service the summated export contributed by all installed inverters installed on any phase must not exceed the Export limit values as per Tables 4.1, 4.2 and 4.3.
For Shared Connection Services please refer to Section 4.3.1.5 which specifies the allowed Export limits.
Export limits depend on both technical capacity and market arrangements:
With an offtake agreement (via your energy retailer): higher export may be allowed, subject to network conditions.
Without an offtake agreement: export is capped at 1.5kW to avoid uncontrolled energy flows when demand is low.
Yes, the export limit will be based on the offtake agreement with the energy retailer and the network category. The export limit may be 1.5kW to 5KW. The site does not need to be generation limited as the total inverter capacity is only 10kVA, and this is equal to the site generation limit for small networks and less than the 15KVA site generation limit for large networks. If you exceed the site generation limit the system can still be installed, however, it will need to site generation limited in accordance with the network category requirements.
DER management coordinates embedded generation to keep the network stable:
- Emergency DER management (since 2022) curbs generation output during very low system demand.
- Advanced DER management supports VPPs and Dynamic Operating Envelopes (DOEs) that adjust export limits in real time, enabling higher exports when the network can accommodate them.
A DOE is a limit set by Western Power on how much electricity a property can import from, or export to, the grid. This limit is based on the available capacity in the network and can change over time to keep the system running safely and efficiently.
Yes. Emergency Solar Management applies to DEBS (Distributed Energy Buyback Scheme) customers which covers inverters less than or equal to 5kVA in size. Under the updated Basic EG CTR solar inverters that are greater than 5kVA and have an offtake agreement with their energy retailer will also need to comply with Emergency Solar Management. Where customers do not have an offtake agreement with their energy retailer their export limit will be set at a static 1.5kW irrespective of inverter size.