Why choose a central power supply system (CPSS) and where should it be installed?

In public buildings or ERP (“Établissements Recevant du Public”) in France, emergency lighting plays a major role in ensuring the safety of occupants. It guarantees quick and safe evacuation in the event of a power outage, even under extreme conditions.

Among the available safety lighting solutions, central power supply systems (CPSS) meet the most stringent requirements.

They are especially recommended in complex environments (large surface areas, high footfall, architectural constraints, or scenographic challenges), where CPSS emerge as the preferred and most robust solution.

Let’s find out more about the specific features and benefits of central power supply systems (CPSS).

What is a CPSS and how does it work?

A CPSS (Central Power Supply System) is an emergency lighting device designed to power emergency lighting units without a built-in battery. It is specifically designed to maintain power continuity during a grid failure. Thus, it ensures immediate lighting activation and reliable safety for building occupants.

Unlike self-contained emergency lighting units (BAES), these luminaires are powered remotely. The CPSS is typically housed in a secure technical room, from where it provides regulated direct energy (24 V, 48 V, or 216 V depending on configuration), in compliance with standard NF EN 50171, which defines the technical and safety requirements for CPSS in France.

What Are the Advantages of Using a CPSS for Emergency Lighting?

Choosing a CPSS setup for emergency lighting brings two major advantages: streamlined maintenance for luminaires and compatibility with visually sensitive environments.

Simplified maintenance and reduced costs

In autonomous systems, each unit contains its own battery, which must be checked, tested, and replaced individually. This increases both labor time and the potential for human error.
With a CPSS, a shared battery powers all connected luminaires. This brings several benefits.

• Centralized control: one access point oversees the entire lighting system, enabling easier fault diagnosis and intervention.
• Faster regulatory inspections: periodic testing becomes more efficient, aligning with the French decree of 25 June 1980 (articles EC 8 to EC 11).
• Extended lifespan: CPS luminaires benefit from a controlled environment, which improves performance and reduces replacement frequency.

Darkness preservation in light-sensitive spaces

When paired with a panic switch, CPSS luminaires allow ambient lighting to remain off under normal conditions while automatically switching on in emergencies. This is not permitted with autonomous units, which must remain permanently visible.

This feature is ideal for type L public buildings (cinemas, theatres, auditoriums) where darkness is essential for audience experience and scenographic integrity. CPSS also offer seamless integration into museums, ensuring visitor comfort and curatorial lighting remains undisturbed.

What types of projects benefit most from CPSS?

CPSS emergency lighting is ideal for complex or sensitive spaces where safety, continuity, and integration are critical. Here are some of the most typical use cases.

A smart fit for complex infrastructure

CPSS systems are especially suited for:

• – high-occupancy public buildings where rapid, reliable evacuation is essential (e.g. hospitals, universities, shopping centres, correctional facilities);
• – classified industrial sites (ICPE or “Installations Classées pour la Protection de l’Environnement”) and facilities requiring uninterrupted, centralized power;
• – heritage buildings or high-end architecture projects where aesthetics and compliance must coexist.

An advantage for cinemas

Entertainment halls, cinemas, theaters, auditoriums and other type L ERP facilities require safety lighting that complies with standards, but is also discreet and visually controlled, without being totally invisible.
The LSC system meets these requirements perfectly: it preserves the darkness necessary for the smooth running of screenings or performances, while ensuring the safety of the audience. Its recessed luminaires, customizable (colors, finishes) and devoid of visible indicators, integrate harmoniously into demanding scenographic or architectural environments.

What does NF EN 50171 say about CPSS?

Published in July 2001, the NF EN 50171 standard defines the requirements for CPSS in France. It applies to fixed installations supplying emergency lighting in case of main power failure.
This standard defines minimum performance levels and specific technical requirements designed to ensure reliability, safety, and service continuity. Key compliance points are as followed.

• A dedicated power source: CPSS must be used exclusively for emergency lighting.
• Minimum 1-hour autonomy, extendable based on building risk level (as per the decree of 25 June 1980 and articles R. 4227-13 to R. 4227-16 of the French Labour Code).
• Continuous standby power: lighting must activate immediately on power loss, with sufficient monitoring points to detect faults.
• Stable regulated voltage with minimal fluctuation.
• Independent circuits, each protected by individual fuses or circuit breakers (no breakers allowed inline with luminaires).
• Audible and visual alarms for errors (e.g. overload, battery failure, charger malfunction).
• Battery temperature control, typically between +5 °C and +25 °C, to ensure performance and lifespan.
• 80% recharge capability within 12 hours after discharge.

In scenographic or architecturally sensitive settings, CPSS luminaires offer a robust, regulation-compliant, and design-conscious emergency lighting solution. They provide not only safety and continuity, but also aesthetic harmony and long-term reliability.

Architects and electrical designers are encouraged to integrate CPSS early in project planning. With our expertise, tailored solutions can be developed to meet both legal obligations and the technical and visual demands of each space.