Lux Intelligent - Knowledge Base

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What is the difference between Maintained and Non-Maintained luminaires?

The terms Maintained and Non-Maintained are used to describe the mode of operation for an emergency lighting luminaire, and the decision on which mode of operation to use is determined by the use of the permises.

Maintained Emergency Luminaire

This is a luminaire in which the emergency lamps are lit all the time.  Maintained mode is generally employed in places of assembly such as theatres, cinemas, clubs etc.  The lights are typically dimmed when the premises are occupied, and the emergency escape lighting prevents total darkness.

Non-Maintained Emergency Luminaire

This is a luminaire whose lamps only come on when the power supply to the lighting fails.  Non-Maintained lights are typically found in the work place where artificial lighting is normally deployed whilst the premises are occupied.

The classification of Maintained and Non-Maintained mode of operation can be further broken down or defined with the following classifications.

Combined Emergency Luminaire

This is luminaire which contains 2 or more sets of lamps, at least one of which is powered from the Emergency Lighting supply and the other(s) from the normal mains power supply.  A combined emergency lighting luminaire can be either Maintained or Non-Maintained.

Compound self-contained Emergency Luminaire

This is a luminaire which operates in either Maintained or Non-Maintained mode, and also acts as the emergency lighting power supply to a satellite luminaire.

Satellite Emergency Luminaire

This is a luminaire which operates in either Maintained or Non-Maintained mode, and which derives it's emergency operation supply from an associated compound self contained emergency luminaire.

Are there different types of Emergency Lighting Systems?

One way of classifying the type of Emergency Lighting System is based on how the emergency light has it's power supplied.

The emergency light could contain it's own power supply, in the form of a battery, and this is referred to as Self Contained or Single Point.

Similarly the power could be supplied from a central battery source, where a battery is located somewhere within the premises and the power is supplied to  the emergency light via cabling.

Generally, the decision to use either a central battery or a self-contained system is likely to be cost determined. If an installation has longevity and low maintenance as priorities, then the higher cost of a central battery may be acceptable on a very large project. Typically, luminaire costs and installation costs are a major consideration, particularly on smaller jobs, and it is this criterion which makes the self-contained luminaire the most popular choice.

Self Contained or Single Point


  • The installation is faster and cheaper as additional power cables do not need to be run
  • Standard wiring material can be used, as opposed to fire resistant cables required for central battery source
  • Burn through of the mains cable will automatically satisfy the requirement for the luminaire to be lit
  • Low maintenance costs - periodic testing and general cleaning required
  • Low hardware equipment costs - no requirement for extended wiring, extra ventilation etc
  • Greater system integrity as each luminaire is independant of the others
  • System can easily be extended with additional luminaires
  • No special sub-circuit monitoring is required


  • Environmental conditions may vary across the system, and batteries may be affected by relatively high or low temperatures
  • Battery life is limited to between 2 and 4 years, dependant on the application
  • Testing requires isolation and observation of each luminaire individually

Central Battery Source


  • Maintenance and routing testing is easier, with only one location to consider
  • The life of the battery is between 5 and 25 years, dependant on type
  • Environmentally stable in a protected environment.   The luminaire can operate at relatively high or low temperatures with no affect on the battery
  • Large batteries are cheaper per unit of power and luminaires are usually less expensive


  • High capital equipment costs
  • The cost of installation and wiring is high due to the requirement for fire resistant cable like MICC or Pirelli FP200 to each luminaire
  • Poor system integrity - failure of the battery or wiring circuit at any point can result in failure of a large part of the system
  • Requirement for a "Battery Room" to house batteries and charging circuits, and potential requirement for ventilation systems
  • Localised mains failure in an area of the premises may not trigger the operation of the emergency lighting in that area


What responsibilities do I have regarding emergency lighting?

The Regulatory Reform Order puts the legal responsibility for the provision, ongoing maintenance and regular testing of emergency lighting installations firmly with the senior directors of the businesses occupying buildings.  It also applies to many public building such as hospitals, universities, colleges and local government.