Wiki: Outdoor lighting

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==Lighting types=The available lighting types are covered in the [[Lighting]] article. The types most often used outdoors are [[filament lamp]], linear [[halogen]], [[CFL]] and [[Discharge lighting|sodium]]. [[LED]]s are now becoming a realistic option too for city gardens. * Low pressure sodium ** extremely high energy efficiency ** pure yellow light ** 9 minute warmup time so only for photocell use * High pressure sodium ** very high energy efficiency ** golden orange light ** slow warmup, so only for photocell use. * White sodium ** a variation of HPS. Whitish light, but lamp colours tend not to match each other well. Good where one is used, less so where more are used. * HID ** very high efficiency ** good white light, but pick the right colour temperature bulb. ** lamps can explode at end of life. * Linear fluorescent ** very high efficiency ** can be fitted under soffits, but not very warm & homely. ** Pick an electronic ballast suitable for sub-zero starting. ** Can be used on PIR, tube life suffers quite a bit in hours, but not in days of use. * CFL ** medium to high energy efficiency ** Light output can be reduced and warmup time prolonged in subzero weather. Lamps immune to this are available. ** PIR use reduces bulb life * LED ** high energy efficiency ** Light quality tends to be cold ** Some LEDs fade with use ** Various colours available for parties etc * Mercury ** horribly cold white light ** medium energy efficiency ** obsolescent * Halogen, linear ** low energy efficiency ** often far too bright * Halogen reflector lamps, low voltage ** can light individual trees & other features ** don't overdo the wattage, 50w is generally excessive outdoors * Halogen reflector lamps, mains ** as above but lamps fail easier & earlier and produce less light. ** Best avoided. * Filament ** lowest energy efficiency, high run cost if kept on. Best only used on a PIR because of this.
==Control methods====Switch==Lights get left on by mistake, and the switch is often not where you need it. Wasteful of energy & money, inconvenient, and a trip hazard. Pets paws can be badly injured by being trodden on in the dark.
===PIR==PIRs (passive infra-red) detect the movement of warm bodies, and switch off after a short time of no detected movement. These are usually the best option for outdoor lighting, but like anything they have their issues.
* detector angle & positioning
The switching device in a PIR is either a relay or a triac. Triacs are a bit cheaper, but are prone to being killed when a filament lamp blows (halogens included). Also triac PIRs tend to not behave ok with CFLs. Relays click when switching, triacs are silent.
* extending pir range, how the lenses work
===Timer==As dawn & dusk times varies considerably, timers are wasteful of energy, and the unnecessary on time reduces lamp life in days (though not in hours). Timers should be replaced with a photocell when a light needs to be on all night, or with a PIR when the lamp type and application are suitable for that.
===Photocell==Switches on when it gets dark, switches off when it gets light. Take care over setting the light level switching points, they're often left set way off. Clean the light detecting cover occasionally.
Photocells run lamps much more of the time than PIRs, and a PIR is preferable when suitable.
Photocells can also be combined with a timer, if for example you want lighting on from dusk to midnight.
===Split control==Where more than one light fixture is used, if they cover different areas its often an advantage to control them separately, reducing total energy use.
===Multiple control==Large sites can benefit from multiple control methods, eg an 18w sodium lamp on all night providing low level security lighting, and white lighting on a PIR for security and access.
==Common issues====Wattage==Lighting of unsuitable wattage is often found, especially when linear halogen is used. The prime offender is 500w linear halogens. End users should also be aware that that LEDs & all types of discharge lighting put out several times as much light per watt than filament lamps.
===Height=====Glare==Its best to avoid lighting up roads, neighbouring properties, adjacent hillsides etc. It annoys people, and wastes light youre paying for, so you need a higher wattage lamp at greater cost to do the job. It can also create an accident risk on roads, and consequent legal liability.
Carriage style light fixtures can have glass panels removed and replaced with sheet ali or mirrored glass to cut down on lost light. No, not all of them :)
===Light pollution==Any light that heads upwards is money and energy wasted, and causes problems for astronomers. Many decorative fittings are far from ideal in this respect. High power fittings such as halogens should always be set to eliminate light pollution.
===Placement==Positioning a light fitting above the entrance door has the advantage that it lights up the visitor's face, and doesn't create glare for the person indoors. A light further away can do the exact opposite on both counts.
===Relamping==Relamping fixtures mounted high up can be a real issue. This is especially true if you're liable to reach pension age in the current property. If you need a lot of light, a few lights within reach are a lot easier to maintain.
===MICC==MICC cable is unique in that its insulation sucks water vapour out of the air, and its too easy to make end seals that don't remain vapour tight long term. This type of [[cable]] is best avoided for outdoor lighting.
===Water==All fittings should shed rain coming from above, and drain any rain that gets in out of the bottom. Sometimes fittings are seen that don't obey these basics, and they have a habit of eventually filling with water and taking out the power.
===Globe breakage==Glass globes can be shattered if the screws retaining them are tightened at all. Its best to leave a very little bit of movement.
===Screws on fixtures==Screws rust and jam. Screws in aluminium fixtures corrode the ali as well. Replacing them with tied wire avoids this problem.
===Climbing plants & fire==Lamp types vary widely in their ability to set fire to plants. Linear halogens run extremely hot, and plant life must always be kept away from them. Sodiums & LEDs run fairly cool, and can be nestled among foliage.
==Wiring====Old installs==Regulations have become a good bit more demanding in the 17th edition. Lots of old installs exist using T&E clipped direct, which has 2 issues. There is a theoretical risk of cable degradation, but practically it doesn't seem to be a problem. Such [[cable]] can be cut into by secateurs.
==See also=[[Taking electricity outside]] [[:Category:Electrical]]
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