Some facts about street lighting and some common misconceptions
- Street lighting does not need to be adjusted to take account of the change between GMT & BST. Solar clocks and photocells self-adjust.
- Street lights on during the day do not incur any additional energy costs (fixed charge agreed with electricity company).
- Street lighting photo cells fail in the 'on' position to avoid the lamps being left dark at night.
- A common problem with older street lights which contain mechanical clocks is that their timing and lighting up times can be put out of sync, either by general power cuts or by insects jamming the mechanism. In both instances the clocks have to be manually reset.
- All new or replacement street lights are fitted with solid state photo cells, which detect and operate on actual light levels.
- For Dundee's geographical latitude, the photo cells used are calibrated to switch on at 35 lux and switch off at 18 lux. This equates approximately to a lighting up time 20 mins after sunset and a switching off time 20 mins before sunrise.