2-Energy Management - Lighting, Cable choice

Old definition: luminous intensity (luminosity) of 1 candle.

Modern definition (standard international unit): luminous intensity of light at a wavelength of 555 nm over 1.46 10-3 W/steradian.

Luminous flux of 1 cd in a 1 steradian cone (1 sphere/4π).

Illumination (quantity of light/m²) of 1 lumen/m².

Ratio of the luminous flux emitted to the electrical power consumed.

The energy that is not converted into light is dissipated in the form of heat.

The lighting efficiency decreases by 30 to 70% towards the end of the life of the lamp.