Regulations and electrical requirements

Binding standards

Electrical installation and grid connection

• NIV: Ordinance on Low-Voltage Electrical Installations (SR 734.27)
• NIN SN 411000:2025: Low-Voltage Installation Standard, in particular chapter 7.12 “Photovoltaic and energy storage systems”
• VSE NA/EEA-NE7-CH:2025: Grid connection of energy generation systems, including annex E (protection setting values for Switzerland)
• VDE-AR-N 4105: Generation systems on the low-voltage grid (D-A-CH implementation of grid connection protection)

Safety of stationary energy storage systems

• ESTI Guideline No. 220: Requirements for stationary energy storage systems
• SNR 460712: Safety of stationary battery energy storage systems

Distribution system operator (DSO)

Take the technical connection conditions (TAB) of the relevant DSO into account and submit them as part of the technical connection application (TAG).

Caution

Work on the HV-DC side (approx. 320–400 V DC) must only be carried out by qualified specialists with the appropriate HV qualification. The storage system uses reused (second-life) automotive LFP battery packs.

HV-DC side

Danger

The system carries a DC voltage of approx. 320–400 V DC. Contact with live parts can cause life-threatening injuries from electric shock or an electric arc. Ensure the system is de-energised, and verify it, before starting any work.

• De-energise the system completely before working on the HV-DC side.
• Open the internal high-voltage contactors by switching off the control or 12 V supply, or by triggering the HVIL loop.
• Check that there is no voltage at the HV terminals.
• After switching off, wait at least 5 minutes for the system to discharge.
• Keep all high-voltage DC components (> 120 V DC) protected against accidental contact at all times.
• Only disconnect high-voltage connectors when they are de-energised.

Insulation monitoring

Insulation monitoring on the DC side is done entirely by the battery pack. It tests the insulation automatically before closing the internal high-voltage contactors, and does not close them if it detects a fault. It repeats the test regularly during operation. Additional DC insulation monitoring on the inverter is not required.

AC side

• Connect the inverter (Solis S6-EH3P) to the grid with a fixed direct connection. Plug connections for the grid connection are not permitted.
• Carry out the grid connection according to the national installation regulations. Only a qualified electrician may do this.
• Fit the AC side with an all-pole isolating device (system switch).
• Install a separate fuse for the AC connection of the battery storage system.
• Install a separate energy metering system if the DSO requires it.
• Grid and system protection (NA protection) is provided by the inverter. During commissioning, set the protection parameters for Switzerland and secure them against unauthorised changes.
• Implement residual current protection according to the inverter manufacturer’s specifications. Provide an emergency shutdown if the DSO or the fire safety regulations require it.

Marking

• Label all isolation points, in particular the AC system switch and any emergency shut-off.
• Affix a notice to the domestic distribution board indicating the battery storage system and the possibility of power feed-back.
• Label the installation site as a battery energy storage system.