SolaX X3 three-phase EPS enclosure - Automatic back-up power supply 3x63A

EPS SolaX X3-EPS BOX - Three-phase 3x63A Automatic Backup Power Supply

The EPS SolaX X3-EPS BOX (reference X3-EPS-BOX) is a professional automatic accessory designed to guarantee the continuity of your three-phase power supply in the event of a mains failure. Thanks to its two integrated three-phase contactors, this box intelligently manages switching between the public three-phase grid (400/230V) and the EPS (Emergency Power Supply) output of your SolaX X3 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 three-phase grid and safely deactivates the EPS output. This solution is essential for commercial and industrial photovoltaic installations with batteries that require autonomy during power cuts.

Automatic operation of the Dual Three-Phase Contactor

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

• Three-phase mains outage detection: The contactor constantly monitors the presence of the 3 phases of the public network.
• Immediate three-phase EPS activation: As soon as a fault is detected (loss of one or more phases), the contactor automatically switches to the three-phase EPS output (powered by battery + PV).
• Automatic reconnection: When a stable three-phase grid returns, the box reconnects the UPS to the public grid and closes the EPS output.
• Three-phase anti-islanding safety: Prevents any injection into the grid during outages, compliant with three-phase decoupling standards.
• Fast switchover time: Switchover in less than 0.5 seconds to minimise interruption.

This operation is totally transparent to the user: no manual intervention is required, even during micro outages.

Compatibility with SolaX X3-Hybrid inverters

The EPS box is compatible with all SolaX X3 series three-phase hybrid inverters equipped with the EPS function:

• SolaX X3-HYBRID 5.0-D G4/G4.2 (5 kVA three-phase)
• SolaX X3-HYBRID 6.0-D G4/G4.2 (6 kVA three-phase)
• SolaX X3-HYBRID 8.0-D G4/G4.2 (8 kVA three-phase)
• SolaX X3-HYBRID 10.0-D G4/G4.2 (10 kVA three-phase)
• SolaX X3-HYBRID 15.0-D G4 (15 kVA three-phase)
• SolaX X3-Retro Fit three-phase models with EPS function

Essential requirements: The UPS must be equipped with a three-phase EPS output and connected to a battery (Triple Power, Pylontech, etc.). Without a battery, the back-up function will not work. The mains supply must be three-phase 400/230V 50Hz (European standard).

Detailed Technical Specifications

Applications for Commercial and Industrial Photovoltaic Installations

The three-phase EPS box meets the critical needs of professional solar installations with storage:

• Commercial buildings: Automatic power supply to critical systems (servers, cash registers, security lighting, alarms) during mains failures.
• SMEs and workshops: Continuous operation of light three-phase machines, compressors, air conditioning, industrial ventilation.
• Data centres: Back-up power supply for critical IT equipment in addition to UPS.
• Farms: Power supply for irrigation pumps, greenhouse ventilation, dairy cooling systems.
• Tertiary installations: Offices, medical practices, shops requiring three-phase power continuity.
• Optimised professional self-consumption: Maximises use of stored solar energy, even in the event of a power cut, reducing operating costs.

Typical use: A workshop equipped with a SolaX X3-HYBRID 10.0-D inverter with an 11.6 kWh Triple Power battery. In the event of a mains failure, the EPS box automatically switches to the battery to supply the priority three-phase circuits (3x63A max, i.e. ~43 kVA). Solar production continues to charge the battery if the sun shines, extending the autonomy.

Three-phase electrical installation and connection

Three-phase electrical requirements:

• Installation by a qualified electrician with three-phase electrical clearance, in compliance with NF C 15-100 (France) / RGIE (Belgium) standards.
• Cable cross-section: 16 mm² minimum for three-phase 3x63A AC input, 16 mm² for three-phase EPS output.
• Suitable four-pole circuit breakers: 63A on mains side, 63A on EPS side.
• Four-pole differential protection 30mA type A compulsory.
• Check that the EPS three-phase output is present on the inverter (X3-Hybrid-D models).
• Check the order of the phases and neutral before commissioning.

Connection steps:

1. Fix the EPS box close to the three-phase electrical panel (external wall mounting possible thanks to IP65).
2. Connect the main three-phase AC input to the public mains (3 phases + neutral + earth, 3x63A max).
3. Connect the three-phase EPS input to the EPS output of the SolaX X3 inverter (3 phases + neutral + earth).
4. Connect the three-phase load output to the priority circuits to be supplied as back-up.
5. Check the phase order using a sequence indicator (L1-L2-L3).
6. Set the differential protections and check the voltage on each phase before commissioning.
7. Test automatic switching by simulating a mains failure (main circuit breaker opened).
8. Check the switching time (< 0.5s) and the stability of the EPS power supply.

Installation tip: Use standard coloured cables (black/brown/grey for L1/L2/L3, blue for neutral, green/yellow for earth). Clearly label terminals to facilitate future maintenance. Document the order of the phases to avoid errors during servicing.

Sizing the three-phase EPS load (3x63A maximum)

The three-phase EPS output is limited to 3x63A (i.e. approximately 43 kVA at 400V three-phase). It is crucial to size the emergency circuits correctly to avoid overloads :

Important advice: Favour balanced three-phase loads (equal distribution over the 3 phases). Avoid connecting very high starting machines (motors >15 kW) directly to the EPS output. For large inductive loads, use a soft start or star-delta start.

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

Standards and Conformity Belgian Three-Phase Network

The SolaX X3 EPS box complies with the three-phase photovoltaic connection standards applicable in Belgium:

• Synergrid regulations C10/11: Guarantees automatic three-phase decoupling in the event of a grid fault (loss of one or more phases).
• Three-phase anti-islanding protection: Prevents electricity from being injected into the public grid during outages (safety of DSO technicians).
• Overvoltage category III: Resistance to transient overvoltages in three-phase industrial installations.
• CE marking: Conforms to the European Low Voltage Directive 2014/35/EU and the Electromagnetic Compatibility Directive 2014/30/EU.
• IP65: Totally watertight for outdoor installation in compliance with Belgian RGIE requirements.
• RGIE installation: Must be carried out by an approved electrician for validation of compliance and professional insurance.

For any technical questions about three-phase installation, consult our support centre or our technical guides.

Advantages of the EPS Three-Phase Box for Your Professional Solar Installation

• Total three-phase automation: No manual intervention during mains outages, even partial ones (loss of 1 phase).
• Reinforced industrial safety: Protects against the risks of three-phase islanding and energy return on an interrupted grid.
• Universal SolaX X3 compatibility: Works with the entire X3-Hybrid range from 5 to 15 kVA three-phase.
• Simple professional installation: Simplified connection (6 wires) between inverter and EPS box, reducing wiring errors.
• IP65 robustness: Outdoor installation possible, weatherproof and resistant to industrial environments.
• Fast switching: Switching < 0.5 seconds to minimise impact on sensitive equipment.
• Proven reliability: robust three-phase electromechanical contactors for maximum longevity in professional environments.
• Professional cost-effectiveness: Fully exploits your battery investment by ensuring autonomy during outages, avoiding production losses.

🔗 Recommended complementary products

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

SolaX X3-HYBRID 10.0-D inverter

Inverter SolaX X3-HYBRID 15.0-D

Inverter SolaX X3-HYBRID 8.0-D

Inverter SolaX X3-HYBRID 6.0-D

Need help choosing the right accessories for your three-phase installation? Consult our technical blog or our support service.