TRT have prepared the following technical information for our customers:

Maintenance Factors for TRT Luminaires

When designing a road lighting scheme with TRT lanterns, the maintenance factors to be used for CLO & NON-CLO designs are different. The maintenance factor design guides (Maintenance Factors for Non-CLO Luminaires & Maintenance Factors for CLO Luminaires) provide an in-depth explanation of how to calculate maintenance factors for TRT luminaires and are aligned with BS5489-1:2020 Annex C.



All luminaires provided by TRT for installation onto an unmetered supply have Elexon approved UMSUG codes ready to use.

To view our list of approved codes, please visit Elexon's Charge Codes and Switch Regimes and select Manufacturer Equipment LED Range Spreadsheet' and filter by manufacturer.


OptiSet by TRT, is a patented optical distribution feature available in certain luminaires provided by TRT, for example the Optio luminaire.

OptiSet allows the Lighting Designer and End User to have the ultimate flexibility within one product to ensure that the application is lit in the most suitable and sustainable way. Optical adjustments can be made when the luminaire is installed or in the depot.


PowerSet by TRT is an innovative power selection module that provides the End User with the flexibility to easily adjust power and lumen output whilst the luminaire is installed or in the depot.

The PowerSet feature allows for reduced stock holding and each module is specifically designed for all luminaires provided by TRT Lighting.

CCT Graph

Correlated Colour Temperature for LEDs

Correlated colour temperature, or more commonly referred to as colour temperature or CCT is a standardised metric used within the lighting industry that defines the colour appearance of a white light source. The unit of measure for this metric is in Kelvin (K) and the lower the Kelvin value, the warmer (or more orange) the light source will appear. Conversely, the higher the Kelvin value, the cooler (or more blue) the light source will appear.

In general, cooler colour temperatures LEDs will have a higher blue light content than warmer colour temperatures. The content of blue light within a given CCT can be seen in a Spectral Power Distribution (SPD) graph, and a relative comparison can be made between differing CCTs.

This graph is a comparison of a 4000K LED and a 2700K LED.

Note, the lumen output for the light source is the same for both CCTs.