Outdoor lighting installation differs from indoor work in three main ways. The fitting has to be built for weather and installed so water cannot reach the connections. The circuit needs RCD protection, the safety device that cuts the power quickly if current leaks to earth. And getting power to the light usually means a cable route through an external wall, along a fence or under a garden, which is where most of the work and most of the risk lie. Indoor lighting is mainly about compatibility, ceiling access and switching, with one big exception: bathrooms, which follow rules closer to those for outdoors.
This guide sets out those differences so you can plan a lighting job, choose suitable fittings and know which parts need an electrician.
How the requirements compare
| Consideration | Living rooms, bedrooms, halls | Bathrooms and shower rooms | Outdoors |
|---|---|---|---|
| Water and dust | Not usually a factor | Steam and splashing; how much protection is needed depends on how close the fitting is to the bath or shower | Rain, frost, dirt and insects; fittings must be rated for their exact position |
| RCD protection | Expected on modern installations | Required on all circuits in or passing through the room | Advised for all outdoor electrical equipment |
| Getting power there | Usually an existing ceiling rose or wall point | Usually an existing point, but any alteration is notifiable work in England | Often a new route through an outside wall, and sometimes a new circuit |
| Mounting | Ceilings and walls, often with void access | Ceilings and walls, often enclosed fittings | Brick, render, timber cladding, fences and posts, each fixed differently |
| Controls | Switches and dimmers | Pull cords or switches outside the room | Motion (PIR) sensors, dusk-to-dawn photocells, timers or indoor switches |
| Typical failure | Dimmer and LED incompatibility, worn switches | Corrosion and moisture getting into unsuitable fittings | Water getting in, corroded terminals, sensors that stop triggering |
Reading an IP rating
Light fittings intended for damp or outdoor locations carry an IP (ingress protection) rating, written as IP followed by two digits. The first digit describes protection against solid objects and dust; the second describes protection against water. An X in place of a digit means that part was not rated. In broad terms:
- IPX4 or IP44 means protection against splashing water from any direction. This is a common rating for bathroom fittings away from the bath or shower and for wall lights in sheltered outdoor spots, such as under a porch.
- IP65 means dust-tight and protected against jets of water. It suits exposed walls, driveways and fittings that face the weather.
- IP67 and IP68 mean protection against immersion. Ground-level uplighters and fittings near ponds or in areas that flood after heavy rain need this level.
Two cautions apply. A rating only holds when the fitting is installed as the manufacturer intends: the cable entering through the correct gland, seals seated properly and the fitting mounted the right way up. And the rating printed on a product is only as good as the product. Electrical Safety First tested outdoor products bought through online marketplaces and found that most of them failed water ingress tests, warning that being sold as “outdoor safe” does not guarantee a product meets the safety standards for outdoor use (Electrical Safety First). Buying from an established retailer or manufacturer is part of choosing a safe fitting.
Getting power to an outdoor light
Indoors, a new light usually connects to wiring that is already in the ceiling. Outside, the supply route is often the biggest part of the job, and there are four broad ways to do it:
- Through the wall from an indoor circuit. A wall light or security light beside a door is often fed through the wall from a nearby lighting circuit. This is usually the simplest mains option where the existing circuit is suitable.
- A new circuit from the consumer unit. Lighting a whole garden, an outbuilding or a long driveway may justify a dedicated circuit. That is a bigger job and, in England, notifiable work (see below).
- Cable run into the garden. Cable taken along fences or across a garden has to be suitable for outdoor use and protected against damage, and buried cable must be laid where it will not be hit by a spade or fence post. Electrical Safety First advises care when digging in a garden because cables may be buried there (Electrical Safety First), which is one reason to keep a record of where any new cable goes.
- Low-voltage and solar kits. Plug-in low-voltage garden lighting runs from a transformer, which needs a suitable socket and a dry location. Solar lights need no wiring at all but give less, and less reliable, light in winter. Both suit decorative lighting better than security lighting.
Whatever the route, outdoor circuits should be RCD-protected. Electrical Safety First’s advice is to use an RCD with all outdoor electrical equipment. If you are not sure whether your consumer unit has RCD protection, our guide to the difference between a consumer unit and a fuse box explains how to tell.
Where Part P comes in
Since the 2013 changes to Part P of the Building Regulations in England, outdoor lighting work is notifiable only if it involves installing a new circuit. Adding a light to an existing circuit outside the house is not notifiable in itself (IET Part P FAQs). Indoors, the same applies, except in a room containing a bath or shower, where adding to or altering a circuit is notifiable (Approved Document P, GOV.UK).
“Not notifiable” is not the same as “no rules”. All electrical work in a home still has to be designed and installed safely to the current wiring regulations, and outdoor work involves water, digging and long cable runs, which is exactly where mistakes cause problems. Wales, Scotland and Northern Ireland have their own arrangements.
Bathrooms: the indoor room with outdoor-style rules
A bathroom is indoors, but water is close to every fitting. Electrical Safety First notes that all circuits in or passing through bathrooms and shower rooms are now required to be RCD-protected, that enclosed ceiling lights are preferable to hanging ones, and that a ceiling pull-cord is a better option than an ordinary wall switch because of damp and wet hands (Electrical Safety First).
The level of water protection a bathroom light needs depends on where it sits relative to the bath or shower. Fittings directly above a shower need a higher rating than a light near the door. Check the manufacturer’s instructions for the zone the fitting is approved for, and remember that the work itself is notifiable in England, which makes a bathroom light a different job from swapping a pendant in a bedroom.
Controls, positioning and the neighbours
Indoor lighting rarely affects anyone outside the room. Outdoor lighting can, and the choice of control and position matters as much as the fitting:
- Motion sensors (PIR) suit entrances and paths, but a sensor that can see the pavement or a neighbour’s garden will switch on all night. Detection range and angle can usually be adjusted.
- Dusk-to-dawn photocells keep a light on throughout darkness, which suits low-output path lighting better than a bright floodlight.
- Aim and brightness. Angling lights down at the area that needs lighting, and choosing a lower output, usually gives better visibility with less glare than a powerful lamp aimed outwards.
This is not only a matter of courtesy. Artificial light can be a statutory nuisance under the Environmental Protection Act 1990 if it unreasonably and substantially interferes with the use or enjoyment of someone’s home, and security lights are among the examples councils deal with. A council that finds a nuisance can serve an abatement notice requiring the light to be stopped or restricted (GOV.UK).
What to decide before booking
- What the light is for: security, safe access to a door or path, or appearance. This decides the type of fitting and control.
- Where each fitting will go and what it will be fixed to, with photos of the walls, fences or ceiling.
- Whether there is already a supply nearby, such as an existing outside light, an outdoor socket or a lighting circuit just inside the wall.
- The fitting’s IP rating and instructions, if you have already chosen one, so its suitability for the position can be checked.
- For bathrooms, where the fitting sits relative to the bath or shower.
For lights inside the property, including replacing fittings, adding new lighting points and LED upgrades, see our lighting installation and repair service. For entrance, driveway, garden and motion-activated lighting, the outdoor and security lighting page explains how outdoor jobs are assessed. If lights are flickering in several rooms or a lighting circuit keeps tripping, the fitting may not be the problem; our guide to the signs you need electrical fault finding is a better place to start.
