The railway industry seems to favour, and may require, the use of blue sheathed cables for mains voltage emergency lighting. This may be observed at Waterloo station as an example. Most of the high bay lights over the concourse have a single white cable.
Some have two cables, one white and one blue. The white cables supply the normally used HID lamps and the blue cables supply a 150 watt mains voltage halogen lamp from a generator.
The railway industry seems to favour, and may require, the use of blue sheathed cables for mains voltage emergency lighting. This may be observed at Waterloo station as an example. Most of the high bay lights over the concourse have a single white cable.
Some have two cables, one white and one blue. The white cables supply the normally used HID lamps and the blue cables supply a 150 watt mains voltage halogen lamp from a generator.
