Outdoor Christmas lights: IP ratings, transformers and keeping it safe

Almost every set here is rated for outdoors. The part that is not is the plug, and that is where outdoor displays go wrong.

IP ratings

An IP rating has two digits: the first for solids, the second for water. IP44 is protected against splashes from any direction and suits a sheltered position: under an eave, in a porch, on a wall that does not take driving rain. IP65 keeps out dust and takes a jet of water, for lights fixed to a fence or a gutter in the open. IP67 survives temporary immersion and is for lights along a path that floods or round a pond. The rating on a product page applies to the lit cable and LEDs; the transformer and plug have their own, usually lower, rating and must be treated separately.

Where the transformer goes

Indoors, with the low-voltage cable passed out through a window or a wall vent, is the best arrangement. Where the socket is outside, the plug and transformer go in a weatherproof box, a DriBox, closed with the cables through the gaskets and stood off the ground. A plug left in the open is the usual reason an outdoor set trips the breaker after the first rain.

Low voltage

The sets here run the lights at 24V or 31V through a transformer, so the cable in the garden is not at mains voltage. That is why they can be rated for outdoors at all. Do not cut or extend the low-voltage cable; use a set with a longer lead or the connectable ranges.

Fixing lights outside

Gutters take gutter clips, which hook over the edge and hold the cable without screws. Fascias and beams take cable clips every 50cm. Hedges take a net light draped over the top. Fences take cable ties through the frame of a silhouette, or hooks for a string. Trees outside take a cluster set wound up the trunk. Do not fix cable with staples through the sheath.

Timers

Most outdoor sets have a built-in timer: six hours on from when you switch them on, then off, repeating daily. For sets without one, a timer plug indoors does the same job and means the plug is never touched in the wet.

Running cost

LED displays are cheap to run. A 500-LED silhouette draws about 3W, a 1,000-LED icicle set about 6W, an inflatable with its fan 15 to 20W. At the current Ofgem price cap of 26.32p per kWh, a whole front garden of lights on a six-hour timer costs £2 to £4 for the month.

Wind

Peg every stake, cable-tie every frame, and deflate inflatables above about 30mph. Rattan and acrylic figures are light; a brick on the back feet keeps them upright.