Just been looking at some plans for a house extension, and the local building control's notes about lighting provisions required for approval of the plans.

These mirror the recommendations in the Building Regs. Part L:

http://www.planningportal.gov.uk/england/professionals/en/1115314231799.html

For internal lighting at least one high-efficiency fitting:

Quote
44. A way of showing compliance would be to provide lighting fittings {.....} that only take lamps having a luminous efficacy greater than 40 lumens per circuit-watt. {.....} Fluorescent and compact fluorescent lighting fittings would meet this standard. Lighting fittings for GLS tungsten lamps with bayonet cap or Edison screw bases, or tungsten halogen lamps would not.


And for external lighting:

Quote
48. When providing fixed external lighting, reasonable provision should be made to enable effective control and/or the use of efficient lamps such that:

a. EITHER: Lamp capacity does not exceed 150 watts per light fitting and the lighting automatically switches off:

i. when there is enough daylight; and
ii. when it is not required at night; or

b. the lighting fittings have sockets which can only be used with lamps having an efficacy greater than 40 lumens per circuit-watt.


So if going with those "evil" planet-destroying filament lamps, it seems that a photosensor is required to automatically switch off when there is enough ambient light outside.

But what is "automatically switches off when it is not required at night" supposed to mean? confused

How does anyone define "required" in this context? If the homeowner says he wants the lights on all night for security, then he requires them, surely?