Emergency power supply according to DIN EN 50171 for buildings where the technology must never stop in an emergency.

An emergency power supply ensures that critical systems continue to operate when the main power grid fails. These include emergency lighting, fire alarm systems, smoke extraction systems, and evacuation systems. The goal is not to save data, but to ensure that people can leave a building in an orderly manner and that emergency services can enter.

This is precisely the difference compared to a conventional IT UPS. Anyone planning, tendering, or operating special-purpose buildings cannot avoid a central power supply system compliant with DIN EN 50171. This article explains what such systems are needed for, what they must be capable of, and what you should consider when selecting one.

What is a central power supply system (CPSS)?

CPSS stands for Central Power Supply System. If the grid fails, the system automatically takes over. The connected loads are then supplied via a battery or a corresponding energy system.

DIN EN 50171 describes precisely these central systems, for example for emergency lighting and other critical loads. The standard specifies corresponding requirements for battery, monitoring, switching, operating time, and fault indication.

What is an emergency power supply needed for?

Such a system is used wherever certain electrical appliances need to continue operating during a power outage. Typical applications include:

• Emergency lighting in buildings as well as escape and rescue routes
• Fire detection and alarm systems
• Smoke extraction and ventilation systems
• certain fire extinguishing and fire protection systems
• Safety and evacuation systems
• critical facilities in hospitals, assembly halls, high-rise buildings, industrial plants and similar sites

Why a normal IT UPS is not sufficient here

A system compliant with DIN EN 50171 is not simply an ordinary IT or server UPS with a different nameplate. Crucially, the power supply to the connected devices must be essential for safety reasons, and the system must demonstrably meet the applicable requirements for battery, monitoring, switching, operating time, and fault indication. This distinction is precisely what the term UPS refers to when technical planners talk about a separate class of system.

For planners and operators, this means that the documentation is part of the system. In case of doubt, a certification according to DIN EN 50171 is the document that counts during acceptance testing and recurring inspections.

These criteria determine a CPSS

Such systems don't tolerate compromises. You should pay particular attention to these points when making your selection:

• Overload reserve. Consumers draw significantly more power during startup than the nameplate suggests. Check the system's continuous load and short-term overload capacity.
• Galvanic separation. An integrated isolation transformer galvanically isolates the input side and the battery circuit from each other. This is an essential safety feature in this class of equipment.
• Battery and charging behavior. Expected service life, recharging time, protection against deep discharge and a charging current adjustable to match the installed capacity determine how resilient the system really is in an emergency.
• Housing and installation location. Heat- and fire-resistant metal enclosures are standard in this class of equipment, as is a defined degree of protection.
• Maintainability. An integrated maintenance bypass switch allows service work to be carried out without switching off the consumers.
• Reporting and monitoring. Relay contacts, remote shutdown (REPO) and interfaces to building management systems ensure that malfunctions do not go unnoticed.
• Expandability. Additional battery cabinets and parallel-connectable systems create reserves for later changes in use.

What you should clarify early in the planning process

The later such systems appear in the project, the more expensive it becomes. These points should therefore be included in the preliminary planning.

• Installation location and space requirements. The system and battery cabinets require space, access for later battery replacement, and a location that can support the weight.
• Operating duration. The required operating time for connected devices depends on the fire safety concept and the building's use. Clarify this value early on, as it determines the size of the battery system.
• Cable routes and fire compartments. The cables leading to consumers often pass through several fire compartments. Route planning and installation method must be coordinated between electrical and fire protection planning.

EFFEKTA is your partner for security technology

The EFFEKTA Regeltechnik GmbH from Rottweil For over 40 years, we have been developing, manufacturing, and servicing UPS systems, from compact line-interactive devices to modular large-scale systems. For this area, we offer the ELTRUM ISO A CPSS certified according to DIN EN 50171 with 20 kVA or 40 kVA is available, which was specifically designed for critical consumers.

In addition, there are services that often make the difference in projects, such as tender consulting , technical product advice before design, as well as maintenance contracts and service over the entire lifespan of the system.

Our Conclusion

A system compliant with DIN EN 50171 is not an optional extra, but an essential component of building planning. Early planning saves on costly retrofits later and ensures that the necessary documentation is readily available in case of an inspection.

Talk to us about your project. We'll advise you from planning to maintenance.

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