HISbox Fireman Switch – safe disconnection of PV strings in case of fire

Lasttrennschalter mit Motorantrieb in einer Feuerwehr-Box, mit automatischer Wiedereinschaltfunktion
Photovoltaic systems continue to generate electricity even when the grid supply has already been disconnected. This is exactly where the risk arises in case of fire: DC cables inside the building remain energized and can endanger emergency responders. The HISbox Fireman Switch ensures that DC voltage is reliably disconnected in an emergency – automatically, quickly, and in compliance with standards.
Oliver Glenz
Oliver GlenzGet advice now
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Maximum safety when it matters most

In case of fire, every second counts. As soon as the fire brigade disconnects the building's main power supply, the HISbox Fireman Switch automatically de-energizes the PV strings.

This allows rescue teams to safely extinguish fires, and the risks to people and buildings are significantly reduced.

Fire brigades, fire protection authorities, and insurers increasingly demand this solution – the HISbox Fireman Switch meets exactly these requirements.

Why a Fireman Switch is important for PV systems

PV modules continue to produce energy as soon as light hits them. Even in an emergency.

DC-Combiner mit Feuerwehrschalter und automatischer Wiedereinschaltfunktion für 6 MPPT, 1000 V, MC4-Stecker/Buchse

This means:

  • DC cables inside the building remain active without disconnection

  • Firefighting and rescue operations are impeded

  • Risks for emergency responders increase

  • Insurers may impose requirements if disconnection devices are missing

The HISbox DC Fireman Switch disconnects the DC strings at exactly the right point – at the building entry or directly near the modules. This prevents PV cables inside the building from continuing to carry voltage during a fire.

Oliver Glenz
Oliver Glenz

We are happy to advise you on the right Fireman Switch solution

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How the HISbox Fireman Switch works

The operating principle is based on three intelligent triggering mechanisms that work independently or in combination.

As soon as the fire brigade or service personnel interrupts the 230 V supply, the Fireman Switch automatically disconnects the PV strings from the inverter.

Variants for every system architecture

The HISbox series offers a wide range of Fireman Switch variants that precisely adapt to the design of modern PV systems. The combination of modular construction and project-specific design ensures that a Fireman Switch variant is available for every solar system.

1 to 12 MPPT, each with different string counts (ideal for small, medium, and large rooftop systems)

Oliver Glenz
Oliver Glenz

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Application areas and technical highlights

The HISbox Fireman Switch is suitable for all systems where DC cables are routed into the building or where increased fire protection requirements exist.

  • Commercial and industrial buildings

  • Modern rooftop systems with many MPPT inputs

  • Residential buildings where DC cables run through interior spaces

  • Existing systems being upgraded to current fire protection requirements

  • Repowering projects where older PV systems are updated for safety

Whether new construction or renovation – the HISbox Fireman Switch provides the same reliable disconnection function everywhere.

Oliver Glenz

Questions about dimensioning, standards, or integration? We support you from planning to implementation.

Contact us
Oliver Glenz – Sales and Division Management
+49 (0) 6068 9314 430sales@his-renewables.com