The EPS box is a Solax accessory to manage the EPS output of hybrid inverters.
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.

The integrated dual three-phase contactor system provides automated, secure management of your three-phase power supply:
This operation is totally transparent to the user: no manual intervention is required, even during micro outages.
The EPS box is compatible with all SolaX X3 series three-phase hybrid inverters equipped with the 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).
| Paramètre | Valeur |
|---|---|
| ENTRÉE RÉSEAU AC TRIPHASÉ | |
| Tension nominale réseau | 3/N/PE ~ 400/230V |
| Fréquence nominale réseau (Hz) | 50/60 |
| Courant d'entrée réseau maximum | 3 x 63A |
| SORTIE EPS (SECOURS TRIPHASÉ) | |
| Tension nominale EPS | 3/N/PE ~ 400/230V |
| Fréquence nominale EPS (Hz) | 50/60 |
| Courant d'entrée EPS maximum | 3 x 63A |
| SORTIE CHARGE | |
| Tension nominale charge | 3/N/PE ~ 400/230V |
| Fréquence nominale charge (Hz) | 50/60 |
| Courant de sortie charge maximum | 3 x 63A |
| CARACTÉRISTIQUES MÉCANIQUES | |
| Dimensions (L x H x P, mm) | 360 x 220 x 160 |
| Poids net (kg) | 4,85 |
| Indice de protection | IP65 (étanche poussière et jets d'eau) |
| CONDITIONS D'EXPLOITATION | |
| Température de fonctionnement (°C) | -20 à +60 |
| Humidité relative | 0-95% (avec condensation possible grâce IP65) |
| Altitude maximale (m) | 2000 |
| Temps de commutation (s) | < 0,5 |
| Catégorie surtension | III |
| GARANTIE ET NORMES | |
| Garantie standard fabricant | 1 an |
| Conformité | CE |
The three-phase EPS box meets the critical needs of professional solar installations with storage:
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 requirements:
Connection steps:
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.
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 :
| Type d'équipement triphasé | Puissance moyenne (kW) | Intensité approximative (A/phase) |
|---|---|---|
| Climatisation commerciale 10 kW | 10 | 14-16 |
| Compresseur atelier 5,5 kW | 5,5 | 8-10 |
| Pompe circulation 3 kW | 3 | 4-5 |
| Éclairage tertiaire LED (50 spots) | 2 | 3 |
| Serveurs + informatique | 5 | 7-8 |
| Ventilation industrielle | 4 | 6 |
| Système CVC (chauffage-ventilation) | 8 | 11-13 |
| Total recommandé | ≤ 40 kW | ≤ 58 A/phase |
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.
The SolaX X3 EPS box complies with the three-phase photovoltaic connection standards applicable in Belgium:
For any technical questions about three-phase installation, consult our support centre or our technical guides.
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.
SolaX X3 three-phase EPS enclosure - Automatic back-up power supply 3x63A by SolaX is available in our Mounting and accessories catalog. Product weight: 3.0 kg. Reference: X3-EPS-BOX.
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