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Solar panel, EV charging and heat pump installation

Learn more about electrical safety and protection when installing a wallbox, solar panels or heat pump in new construction, modernization project or as part of switching to electromobility. If you are committed to renewable energy, you will find what you need to know here.

Install and protect a wallbox

With a compact AC wallbox, you can safely achieve permit-free charging speeds of up to 11 kW in your own garage. The SENTRON portfolio offers all the protection components necessary for implementing standards-compliant wallbox installations and protecting them against residual currents, lightning, and overvoltage.

Lightning over a residential neighborhood

Power supply line sizing and protection

The cable size depends on the charging power:

  • 11 kW (3-phase, 16 A): Minimum cross-section 5x2.5 mm²: May need to be larger
  • 22 kW (3-phase, 32 A): Minimum cross-section 5x6 mm²

To secure the wallbox power supply line:

  • Circuit protection: SENTRON 5SL6 (3-pole, 16 A or 32 A, B or C characteristic)
  • Residual current protection: SENTRON 5SV3 Type A/F + 6 mA DC residual current circuit breaker
  • SENTRON 5SV3 Type B for maximum safety

If installed in a separate distribution box:

  • ALPHA SIMBOX WP wall-mounted distribution box (8GB1) for standards-compliant installation
  • Protect the supply line with a SENTRON 5SU1 RCBO (4-pole, type A, 16 A or 32 A).

Siemens tip: To comply with VDE standards, a disconnect device must also be provided, e.g. with a main circuit breaker SENTRON 5SP3 (SHU).

Surge protection

Surge protection is strongly recommended if you want to install and connect a wallbox.

Siemens recommends the use of the following for wallbox overvoltage and power surge protection:

Siemens tip: Many network operators require the installation of surge protection for wallbox security as soon as a wallbox is registered.

PV safety during installation

An array of solar panels on a green lawn.

RCDs for PV protection during installation

A residual current device (RCD) type B is required for electrical protection on the AC side of the PV system because inverters can generate smooth DC fault currents that a classic Type A residual current device (RCD) does not detect.



Siemens recommends the SENTRON 5SV3 Type B residual current circuit breaker (RCCB) for PV protection during installation, as it:

  • Detects sinusoidal alternating and pulsating direct fault currents and smooth DC fault currents
  • Offers a reliable protective device for personal safety

Surge protectors to protect PV systems against damage

According to DIN EN 62305-3 Supplement 5, a surge protection measure is required for PV installation if:

  • no external lightning protection is present
  • the PV system contains sensitive inverters or other electronic components

Siemens offers the SENTRON 5SD7 surge arresters for PV protection:

  • to protect the solar modules and the DC wiring (DC side)
  • for AC installations (AC side)

These devices reduce damage from lightning strikes and grid disturbances and increase the lifespan of the PV system.

RCDs and circuit breakers

Choose from a variety of reliable devices for wallbox protection including options for residual current protection (RCD) and circuit breakers.

Siemens tip: If the wallbox has a socket or vehicle connector, additional protective measures against DC residual currents are required. The SENTRON Type A/F residual current device with 6 mA DC detection is an optimal choice.

PV systems line protection requirements

Photovoltaic systems must be protected against overcurrent and short circuits in accordance with DIN VDE 0100-712. The correct circuit breaker (MCB) is crucial for PV protection.



DC side (PV generator – inverter):

  • SENTRON 3VA15 compact circuit breaker (up to 1,000 V DC) for high DC rated currents
  • SENTRON 3NW7 DC fuse as an alternative for individual strings

AC side (inverter – grid connection):

  • SENTRON 5SL6 miniature circuit breaker with suitable characteristics for the AC side
  • Main circuit breaker SENTRON 5SP3 (SHU) for selective protection of the PV connection

These protective measures ensure safe and compliant PV protection and prevent damage from overload or short circuit.

Installing and securing heat pumps

Heat pumps play a vital role in the energy transition. Combined with solar panels, they deliver an efficient solution for sustainable, cost-effective energy. Learn what you need to know to make the right choice and protect your heat pump before installation.

A solar panel system installed on a residential building.

Required residual current circuit breakers

Heat pumps with inverter technology can generate smooth DC residual currents that a conventional Type A residual current device (RCD) cannot reliably detect. Therefore, DIN EN 62423 (VDE 0664-40) mandates the use of a Type B RCD to detect sinusoidal AC, pulsating DC, and smooth DC residual currents.

If a Type A residual current device (RCD) is used to protect a heat pump instead of a Type B RCD, DC fault currents can block or delay the RCD's protective function in the event of a fault.

This can lead to dangerous situations, especially if fault currents are not reliably interrupted. Incorrect protection can also violate applicable standards and jeopardize insurance coverage.

Heat pump protection

Heat pump protection is carried out according to the following specifications:



• Heating elements: 3-pole circuit breaker (MCB) B16

• Indoor unit: 1-pole LS B16

• Outdoor unit: 1-pole LS B16

Additionally, a selective main circuit breaker (SHU) is recommended for safe mains disconnection when installing a heat pump.

The energy transition: Challenges and opportunities

Heat pumps and wallboxes place new demands on electrical protection technology. Learn more about how the challenges and opportunities the energy transition brings not only for electricity generation, but also for electrical installation and the electrical trade.

A person wearing protective gear works on an electrical box.

Get your journey started