Backup Power is not interchangeable

Power Control
19 May 2020

Selecting the correct backup power provision for any application is essential but can be difficult to navigate. Understanding the principle differences is key. Looking specifically at Central Battery Systems (CBS) and Uninterruptible Power Supply (UPS) solutions, whilst very similar, it is important to know that they are not interchangeable.  

A CBS is designed explicitly to cope with significantly greater overload protection for life safety applications such as emergency lighting, sprinkler systems, smoke extraction and evacuation lifts.  

Backup power solutions for any of these applications must adhere to a set of government standards and regulations. The most familiar is BS EN 50171. This sets out a requirement for a minimum of 120% permanent overload capacity, 10 year battery design life, automatic circuit breakers for static bypass and rectifiers, and that the charging current must have a 10 hour capacity level and cannot be less than 0.1C10.  

BS EN 50171 also references polarity reversal protection where reversed battery connections can be done without any damage or impact. Discharge protection is also a key safety measure to ensure that batteries are safeguarded against varying levels of discharge current.  

Other regulations such as BS 5266-1 go into slightly more detail on the speed in which power must be restored to any life safety application. A CBS must have the ability to provide and recover 80% autonomy within 12 hours in the event of a mains fail. The final directive to make note of is EN 60598-1 which stipulates that the backup power system must be housed within an IP20 metal enclosure. 

Guidance is also given with regards to operating modes. An ‘Uninterrupted mode’ must have the load continuously fed by the inverter. A ‘changeover mode’ must have the load fed continuously through the bypass and a ‘changeover mode with control switching’ needs to include a switching device for emergency only loads.  

Backup Power Is Not Interchangeable 1


Three Phase
60kVA – 160kVA
Standalone – CPS

Designed in compliance with EN 50171 standards, ideal for for emergency safety systems


BORRI E8031/E8033 ECS

Three Phase
10kVA – 50kVA
Standalone – CPS

Designed in accordance with EN 50171 standards, ideal for emergency safety systems


It can seem more convoluted than it is. All the above policies are easily achievable. Borri Spa for example, has drawn on its manufacturing history and engineered a range of CBS exclusively for life safety applications.  

All the CBS solutions from Borri Spa meet the required regulations and standards. They also come with acid proof battery trays, separate input for rectifier and static bypass with automatic circuit breakers and temperature probes to measure the charging voltage vs ambient temperature compensation. The Borri ECS series is available from 10 – 160kVA with both single or three phase output. The solutions also feature the company’s patented Green conversion technology and are available with backfeed protection contactors for added protection.  

When it comes to understanding power protection and the equipment available, Power Control has had nearly 30 years of experience in the field and has delivered countless solutions for life safety applications within both critical and non-critical environments.  

Trusted by businesses across the country Power Control supplies, installs, commissions and maintains backup power solutions for all applications. For more information please visit, email or call the office on 01246 431431