Glossary of Terms

The higher the Colour Rendering Index (on a scale of 0-100), the more natural the lit object appears. A low colour rendering will alter the perceived colour of an item.

Correlated Colour Temperature (measured in degrees Kelvin) describes the visual warmth or coolness of light. Lamps with a warm appearance have a CCT of 2700-3000K. The higher the number, the whiter or cooler the light appears.

Lux, or illuminance, is a measure of how many lumens is emitted over a square metre. In terms of how much light is reaching a surface, 1 lumen per square metre equals 1 lux.

Circuit Watts is the number of watts used to power a circuit, rather than just the luminaire.

Only a proportion of the light emitted from a light source will emerge from the light fitting; some is lost inside. This is known as the Light Output Ratio.


At Trafford Electrical we have a reputation for sound lighting knowledge, innovative lighting solutions and quality products. Our aim is to supply the most efficient lamps which are not only economical to run, but also have improved performance and longer life.