What is a Central Power Supply System (CPSS)?

Introduction to Central Power Supply Systems (CPSS):

Central Power Supply Systems (CPSS) are vital pieces of equipment across various industries and facilities, providing a centralised power source to critical equipment, such as emergency lighting, fire alarms, security systems, and other essential devices. Also known as Central Supply System (CSS), they play a crucial role in maintaining safety and operational integrity during power outages or emergencies.


Key Features and Components of CPSS:

A CPSS typically consists of several key components, including power sources, distribution units, batteries, and monitoring systems. These systems are engineered to deliver reliable and uninterrupted power to critical loads, ensuring the safety of personnel within a premises. They must be designed in accordance with strict regulations including BS EN 50171 to ensure users of the premises can exit the building safely in the event of a power outage.


As stated within BS EN 50171, a CPSS system must have:

  • A 120% permanent power overload capability for at least the excepted backup time.
  • Battery polarity reversal protection
  • The system includes automatic switches to protect the main input line and the emergency line.
  • After a complete discharge, 80% autonomy can be achieved within 12 hours of charging.
  • Batteries should have a 10-year life expectancy and their sizing should include a design margin as to guarantee autonomy until end of life.
  • A battery charger temperature compensation is provided, following the manufacturer's advice.
  • A deep discharge protection is included avoiding any permanent damage to the system.


Differentiating CPSS from Uninterruptible Power Supply (UPS):

While both Central Power Supply Systems and Uninterruptible Power Supplies (UPS systems) serve to provide backup power, there are distinct differences between the two systems:

A CPSS system is primarily designed to serve as a dedicated power source for life safety equipment such as smoke detectors, emergency lighting, firefighters lifts, fire suppression, across the entire facility.

UPS, on the other hand, are commonly used to provide backup power to critical business applications such as IT equipment, servers, security equipment, passenger lifts, and other non-life safety applications.

CPSS installations are governed by specific standards and regulations, such as EN50171, which define requirements for emergency lighting and power systems in various applications. Compliance with these standards ensures the reliability and safety of CPSS installations.

UPS systems may also adhere to certain standards, but they are not subject to the same level of regulatory requirements as CPSS in critical infrastructure applications.


CPSS Maintenance

Having a regular maintenance contract on a central power supply system is every bit as important as maintaining an uninterruptible power supply. They both contain components which degrade overtime and may cause a serious system failure if left unserviced.

Power Control offer both traditional transformer based and transformerless monolithic CPSS systems and modern modular CPSS systems. All are rated to BS EN 50171 standards, the most suitable solution will depend on the customers individual needs.


Borri ECS – Transformerless Monolithic CPSS

Borri E3000 – Transformer based CPSS

Legrand Trimod MCS – Modular CPSS

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