Christmas lights safety in the UK: plugs, voltage, IP ratings and outdoor use

Last updated: 12 November 2026

This guide is general information, not professional electrical advice. If you are unsure about the wiring or sockets in your home, ask a registered electrician.

Christmas lights spend eleven months in a box and one month switched on for hours at a time, often on a crowded socket. A few checks make them far safer. This guide draws on advice from Electrical Safety First, London Fire Brigade, NICEIC and GOV.UK, and explains what the plugs, voltages and ratings on a product page mean.

The UK supply: 230 volts and a three-pin plug

Mains electricity in the UK is supplied at 230 volts and 50 hertz. Electrical Safety First says that Christmas lights should operate either at mains voltage (230 volts) or at extra-low voltage, typically 12–24 volts, and that all Christmas lights must be fitted with a UK three-pin plug and fuse if they are mains powered.

A UK plug should be marked BS 1363 on the back, and the fuse inside it should be marked BS 1362. If a fuse ever needs replacing, use one of the same rating as the one that was fitted.

Mains or extra-low voltage?

Many LED sets do not run at mains voltage at all. A transformer, usually built into the plug, steps the supply down to extra-low voltage before it reaches the cable. Electrical Safety First describes these as the safest Christmas lights, because the lower voltage significantly reduces the risk of electric shock even if there is a fault or a lamp breaks.

Battery, USB and solar sets are also low voltage and need no mains socket, which makes them handy for wreaths, mantelpieces and table centres. The power type of every set in our Christmas Lights department is given on its product page.

Lights made for a different voltage

Some countries use a supply of 100–127 volts. Lights designed only for that supply are not suitable for UK mains as they are. A travel adaptor does not help: it changes the shape of the pins, not the voltage. Electrical Safety First explains that equipment made for a different voltage needs a voltage converter or transformer, and that the place to check is the rating plate on the product or its power supply. A label such as "INPUT: 110–240V" means it can work on any supply in that range. If the rating plate does not include 230 volts, do not plug the set into a UK socket.

Safety marks: UKCA and CE

London Fire Brigade advises buying fairy lights from a reputable seller and checking that they carry a CE or UKCA safety mark. UKCA stands for UK Conformity Assessed and applies in England, Scotland and Wales. According to GOV.UK guidance, updated in August 2026, the UK continues to recognise the CE marking, alongside or in place of the UKCA marking, for the Great Britain market. Either mark, or both, may therefore appear on a product. Northern Ireland follows separate rules, under which products carry the CE marking, or the CE and UKNI markings together.

A mark records the maker's own statement that the lights comply with safety law; it is no substitute for looking them over yourself.

Check before you switch on

Electrical Safety First recommends a short inspection each year when the lights come out of storage:

• Check that the lights are not damaged or broken and that there are no loose wires.
• Look at the plug and the socket for burn marks, listen for buzzing or crackling, and feel whether the plug gets too hot to touch. Any of these is a reason to stop using the set.
• Replace failed lamps before using the lights, with lamps of the same type and rating as the originals, and never change a lamp while the set is plugged in. If the lamps cannot be replaced, replace the set.
• Take the lights out of the packaging before you connect them to the power.

London Fire Brigade puts it simply: loose wires, blown bulbs or damaged cords are a sign that it is time to replace the lights. RoSPA likewise suggests that if your fairy lights are old, you think about replacing them.

Indoors: sockets, extension leads and heat

December is hard on sockets. Electrical Safety First advises against overloading socket outlets and says it is best not to rely on extension leads or adaptors if you can avoid it. Stand the tree near a wall socket where possible, and lay the cable where nobody will trip over it.

Keep lights well away from flammable decorations and anything else that burns easily. London Fire Brigade warns that bulbs can get hot and should not touch paper or fabric decorations. LED lights use much less power and generate less heat than filament lamps, which is one reason both organisations recommend them. If you light real candles as well, keep them in heat-resistant holders on a stable surface and never on or near the tree. London Fire Brigade describes flameless LED candles as a much safer alternative; candles and holders are in our Indoor Christmas Decorations department.

Outdoors: IP ratings, RCDs and where the plug goes

Do not use lights outdoors unless they are specifically designed for it. London Fire Brigade notes that indoor lights will not survive outdoor use, and that outdoor lights may pose a risk if used indoors, so use each set only as intended.

Outdoor lights are marked with a water-drop symbol or an IP code, a two-digit rating for protection against solid objects and water. Electrical Safety First says the second digit should be three or higher for outdoor use. NICEIC, which certifies electrical contractors, gives a simple rule of thumb: choose outdoor lights rated IP44 or higher, meaning they are protected against splashing water and larger solid objects.

The RCD matters. A residual current device cuts the power quickly if it detects a fault. Electrical Safety First says that any lights plugged in outdoors must be connected through a 30 mA RCD-protected socket; if your consumer unit does not provide RCD protection, use an RCD plug in the socket. It also advises keeping plugs and transformers indoors, even when the lighting is suitable for outdoor use. NICEIC adds that long extension leads should be avoided for mains-voltage equipment outside, because they can lead to overheating and overloading.

The same checks apply to light-up figures, projectors and inflatables in our Outdoor Christmas Decorations department. The rating varies from product to product, so check each product page.

Battery lights and button batteries

Small battery-powered decorations often run on button batteries, which are dangerous if a child swallows one. The Office for Product Safety and Standards advises storing spare button batteries securely and out of children's reach, keeping products whose battery compartment is not secured by a screw away from young children, and remembering that "dead" button batteries can still have enough power to badly hurt a small child. If you think a child has swallowed one, take them straight to the nearest A&E department or call 999 for an ambulance.

At bedtime and when you go out

Electrical Safety First advises switching Christmas lights off and unplugging them before you go to bed or go out. London Fire Brigade gives the same advice and suggests putting them on a timer if you think you might forget. This applies to outdoor displays as well as the tree.

It is also worth teaching young children that Christmas lights are not something to play with, and keeping pets away from the cables.

Packing away

Unplug the lights before you take them down, coil them loosely and, as Electrical Safety First suggests, keep the original packaging to store them in. Do not keep lights anywhere damp, or anywhere excessively hot or cold. A set that is put away carefully is far more likely to pass next year's inspection. Our guide to when to put up and take down your decorations has more on storage, and our guide to how many lights a tree needs helps when it is time to replace a set.

If a set of lights from us arrives damaged or faulty, do not use it: email us with your order number and a photo, as described on our Returns & refunds page. For anything else, the FAQ is a good place to start.

Sources

• Electrical Safety First: Christmas lights
• London Fire Brigade: Christmas trees
• Electrical Safety First: Plugs and fuses
• NICEIC: Gardens and electrics
• Electrical Safety First: Travel adaptors
• GOV.UK: Using the UKCA marking
• London Fire Brigade: Candles
• RoSPA: Christmas safety
• GOV.UK (OPSS): Button batteries campaign