SolaX Power X1 EPS automatic transfer box for single-phase 17A backup power supply

EPS SolaX X1-EPS BOX - Automatic Backup Power Supply for Single Phase Inverters

The EPS SolaX X1-EPS BOX (reference X1-EPS-BOX) is an automatic accessory designed to guarantee the continuity of your power supply in the event of a mains failure. Thanks to its two integrated contactors, this box intelligently manages the switchover between the public grid and the EPS (Emergency Power Supply) output of your SolaX X1 hybrid inverter.

In the event of a mains failure, the box automatically activates the EPS output powered by your battery and solar panels. When the grid returns, it automatically reconnects your installation to the public grid and safely deactivates the EPS output. This solution is essential for photovoltaic installations with batteries that require autonomy during power cuts.

Automatic operation of the double contactor

The integrated dual contactor system provides secure, automated management of your power supply:

• Mains failure detection: The contactor constantly monitors the presence of the public mains.
• Immediate EPS activation: As soon as a fault is detected, the contactor automatically switches to the EPS output (powered by battery + PV).
• Automatic reconnection: When the grid returns, the box reconnects the UPS to the public grid and closes the EPS output.
• Anti-islanding safety: Prevents any injection into the grid during outages, in compliance with decoupling standards.

This operation is totally transparent for the user: no manual intervention is required.

Compatibility with SolaX X1-Hybrid inverters

The EPS box is compatible with all SolaX X1 series single-phase hybrid inverters equipped with the EPS function:

• SolaX X1-HYBRIDE 3.0-D G4/G4.1 (3 kVA)
• SolaX X1-HYBRIDE 3.7-D G4/G4.1 (3.7 kVA)
• SolaX X1-HYBRIDE 5.0-D G4/G4.1 (5 kVA)
• SolaX X1-HYBRIDE 6.0-D G4/G4.1 (6 kVA)
• SolaX X1-Retro Fit models with EPS function

Essential requirements: The UPS must be equipped with an EPS output and connected to a battery (Triple Power, Pylontech, etc.). Without a battery, the back-up function will not work.

Detailed Technical Specifications

Applications for Residential Photovoltaic Installations

The EPS box meets the critical needs of solar installations with storage:

• Essential back-up loads: Automatic power supply for lighting, fridge, freezer, internet box, alarm during mains failures.
• Energy autonomy: uses the battery and PV production to operate off-grid without interruption.
• Optimised self-consumption: Maximises use of stored solar energy, even in the event of a power cut.
• Secure installation: Avoids complex manual disconnections and the risk of wiring errors.

Example of typical use: A house equipped with a SolaX X1-HYBRID 5.0-D inverter and a Triple Power 5.8 kWh battery. In the event of a mains failure, the EPS box automatically switches to the battery to supply the priority circuits (17A max, i.e. ~3.9 kW). Solar production continues to charge the battery if the sun shines.

Installation and electrical connection

Electrical requirements:

• Installation by a qualified electrician in compliance with NF C 15-100 (France) / RGIE (Belgium) standards.
• Cable cross-section: 10 mm² minimum for AC 63A input, 2.5-4 mm² for EPS 17A output.
• Suitable earth leakage circuit breakers: 63A on mains side, 20A on EPS side.
• It is essential to check that the EPS output is present on the inverter ("E" models or recent versions).

Connection steps:

1. Fix the EPS box close to the electrical panel (wall-mounted or in an enclosure).
2. Connect the main AC input to the public mains (63A max).
3. Connect the EPS input to the EPS output of the SolaX inverter.
4. Connect the load output to the priority circuits to be supplied as back-up.
5. Set the differential protections and check the voltage before commissioning.
6. Test the automatic switching by simulating a mains failure.

Installation tip: Use different coloured cables to easily identify the mains input, EPS input and load output. Label the terminals to facilitate future maintenance.

EPS Load Sizing (17A Maximum)

The EPS output is limited to 17A (approximately 3.9 kW at 230V). It is crucial to size the emergency circuits correctly to avoid overloads :

Important advice: Avoid connecting high start-up appliances (heat pump, air conditioning) to the EPS output. Prefer low to medium continuous loads.

To precisely size your back-up requirements, consult our consumption calculator in our toolbox.

Standards and Belgian Network Compliance

The SolaX EPS box complies with the photovoltaic connection standards applicable in Belgium:

• Synergrid C10/11 regulations: Guarantees automatic decoupling in the event of a grid fault.
• Anti-islanding protection: Prevents electricity being fed into the public grid during outages (safety of technicians).
• CE marking: Complies with European low-voltage and electromagnetic compatibility directives.
• RGIE installation: Must be carried out by an approved electrician to validate compliance and provide insurance.

If you have any technical questions about installation, please contact our support centre.

Advantages of the EPS box for your solar installation

• Total automation: No manual intervention during power cuts.
• Reinforced security: Protects against the risks of islanding and of energy being sent back when the grid is cut.
• Universal SolaX X1 compatibility: Works with the entire X1-Hybrid range from 3 to 6 kVA.
• Simple installation: Compact enclosure with clearly labelled connections.
• Proven reliability: Robust electromechanical contactors for maximum longevity.
• Cost-effective: makes the most of your battery investment by ensuring autonomy during outages.

Recommended complementary products

For a complete and optimal installation, discover our compatible products:

SolaX X1-HYBRID 3.0-D inverter

Inverter SolaX X1-HYBRID 5.0-D

Inverter SolaX X1-HYBRID 3.7-D

Need help choosing the right accessories? Consult our technical blog or our support service.