Outdoor lighting
Linear wall lights from thirty to two hundred and forty centimetres, fittings that throw light both up and down, floodlights, decorative globe lamps and lanterns, and coloured outdoor bulbs. A motion sensor picks up best the person walking across its field of view and least well the one heading straight at it, so it belongs beside the path. Insects are drawn by the ultraviolet part, which an LED does not emit, and next by the blue, of which cool white holds more than warm white, so warm white belongs by the house. Outdoor socket outlets and equipment used outdoors must be protected by a residual current device rated at 30 milliamps.
Outdoor lighting
The outdoor lights in this category run on mains power or on a rechargeable battery. You will find linear wall lights from thirty to two hundred and forty centimetres drawing nine to ninety watts, wall lights that throw light both up and down, floodlights, decorative globe lamps and lanterns, and coloured outdoor bulbs for an ordinary lampholder. Some of the fittings are dimmable and can switch the light colour from warm to cool, and a wall-mounted motion sensor is sold separately. The bodies are usually matt black and go up either vertically or horizontally, on a facade, a fence or a post.
A motion sensor picks up most reliably the person walking across its field of view, and least reliably the one heading straight at it. Inside sit two sensitive fields side by side, and the sensor responds to heat passing from one to the other, so walking along the axis changes the signal least. The sensor therefore belongs beside the path rather than facing down it. A separate wall sensor will also switch on a fitting that has no sensor of its own.
A white LED emits no ultraviolet, but it does have a strong blue peak, and blue is the next thing after ultraviolet that draws insects hardest. In a trial with sticky boards, ultraviolet light collected the most insects, blue about a fifth of that, and from orange through deep red almost nothing came. Cool white holds more blue than warm white and drew about half as many insects again, in beetles and moths the difference was established, and in the remaining orders the sample was too small to confirm it. Warm white therefore belongs on the terrace and by the door, because it costs you nothing extra.
An unshielded fitting sends part of its light horizontally and upwards, where it lights nothing for anyone and only dazzles. The international guidance on outdoor lighting is therefore to shield the beam and aim it downwards so that it does not spill beyond the spot it is meant to light. A fitting that throws light up and down looks good on a facade, but for lighting a path half of its output goes to waste. A weaker fitting aimed properly does more work than a powerful floodlight pointed into the neighbour’s garden.
Outdoor socket outlets and equipment used outdoors must, under the standard, be protected by a residual current device with a tripping current of 30 milliamps, and in dwellings that applies to lighting circuits as well. A mains-powered fitting therefore does not belong on an extension lead run out of a window, but on an installation that has such a device. Battery and rechargeable lamps do not have this problem, because no fixed supply runs to them.