GivEnergy inverters support Emergency Power Supply (EPS) functionality to provide backup power during grid outages. This article explains EPS wiring and configuration across multiple installation methods.
For visual representations, please refer to the attached documentation.
Overview
- EPS terminals are powered by the grid when available.
- Upon grid loss, the inverter switches to battery and solar (if available on Hybrid models).
- Overloading the EPS can cause loss of backup for 5+ minutes and may damage the inverter permanently.
Important: EPS must comply with BS7671 and the IET Electrical Energy Storage Systems (2nd Edition) standards.
📎 Diagram Reference:
Please refer to the attached PDF for full wiring schematics, EPS diagrams, and terminal locations.
Please note that a small delay will be experienced following loss of grid before the EPS system energises. This should be approximately 5 seconds.
Supported Inverter EPS Output
Maximum Output (kW) | Gen 1 Hybrid 3.6 / 5kW | Gen 2 Hybrid 3.6 / 5kW | AC Coupled 3 kW |
2.6kWh Battery | 1.25 | 1.25 | 1.25 |
5.2kWh & 8.2kWh Battery | 2.6 | 3.6 | 3.0 |
All Batteries with Solar | 3.6 / 5 | 3.6 / 5 | N/A |
Electrical Connections
The EPS connection can be found under the same cover as the AC input, the EPS terminals are on the left side with the grid terminals on the right.
EPS Output Protection Requirements
- Double pole RCD (max 30mA)
- Overload protection: 6–25A
âš Note: EPS terminals will be live if powered from AC, battery, PV or any combination. Follow isolation procedures before accessing terminals.
DO NOT connect EPS outputs from multiple inverters together.
Earthing in Island Mode
- Do not rely on TNS or TN-C-S earth systems as when grid live is lost grid earth and neutral may also be lost.
- A TNS or TN-C-S earthing system may be left connected when operating in island mode.
- TT earthing required for EPS output circuits.
- Earth electrode resistance (ZEE) should be as low as possible and should be < 200Ω.
- Provide an earth bond between inverter casing and all batteries.
- Grid and EPS earth terminals are not linked inside the inverter.
EPS Connection Methods
Method 1: EPS Socket Outlet via Consumer Unit
- Advantages: Easy to install, minimal load, long backup time
- Disadvantages: Manual user intervention required
Install a socket connected via a small consumer unit to the EPS output. Socket powers loads during normal and backup modes. User plugs in devices as needed.
Earthing:
Socket/consumer unit must be TT earthed.
Method 2: EPS Consumer Unit for Dedicated Circuits
- Advantages: Backs up only essential circuits, reducing overload risk
- Disadvantages: Requires new or re-wired circuits
Install a separate consumer unit fed by EPS output. Connect essential loads. Automatically powered by EPS during outage if battery has capacity.
Earthing:
At minimum, TT earthing is required.
Method 3: Full Property Backup with Manual Changeover
- Advantages: Entire property backed up, user reminder to manage load
- Disadvantages: Manual switching required
Install a manual changeover switch at incoming supply. User must switch to EPS mode during outage. Backup lasts as long as battery allows.
Earthing:
TT earthing required for entire property when off-grid.
Warning: Do not power the inverter from a consumer unit that is fed by the changeover switch.
Method 4: Full Property Backup with Auto Changeover
- Advantages: Fully automatic switching to EPS
- Disadvantages: High risk of accidental overload if heavy loads was switched on prior to grid failure
Install an automatic changeover switch at the main supply. Automatically switches to EPS mode during outage.
Earthing:
TT earthing is required for the entire property during off-grid operation.
Warning: As with method 3, ensure the inverter’s grid supply is not routed from the changeover-fed consumer unit.
Support
If you are unsure about any of the guidance in this article, please contact support@givenergy.co.uk.