How do I put up Christmas lights safely?

Christmas lights cause a predictable spike in both electrical incidents and falls every December, and almost all of it comes from three things: indoor lights used outside, too many sets joined together, and someone reaching from a ladder rather than moving it.

Safety

Step by step

1. Test everything on the ground first.Unpack, plug in, and check every set works before it goes up. Finding one dead section after everything is fixed to a roofline is the classic wasted afternoon.
2. Inspect the cable and plug on every set.Cracked insulation, exposed wire, a damaged plug, or corrosion on outdoor sets stored damp. Any of those means the set is thrown away, not repaired with tape.
3. Use only outdoor-rated lights outside.Check for an IP rating on the box — IP44 or better for outdoor use. Indoor lights outside are not a shortcut; they are the main electrical hazard of the season.
4. Plug outdoor lights into an RCD-protected socket.Either an outdoor socket with RCD protection, or a plug-in RCD adaptor on an indoor socket. This is what protects you if water gets in anywhere.
5. Respect the maximum number of joined sets.Printed on the box. Exceeding it overloads the first set's wiring, which is a fire risk rather than a performance issue. If in doubt, run a second set from a different socket.
6. Set the ladder up properly.On firm level ground, at about one out for every four up, tied or footed by someone. Not on grass that gives, not on a slope, not balanced on anything.
7. Never overreach.Keep your belt buckle within the ladder's stiles. Moving the ladder six more times is tedious; falling once is not. This is the single most broken rule and the single most common cause of injury.
8. Do not work at height alone.Someone at the bottom footing the ladder and aware you are up there. If you are on your own, do the ground-level lights and leave the rest.
9. Fix lights without damaging anything.Purpose-made clips for gutters, ridge tiles and brick, or exterior-grade adhesive hooks. Never nails or staples through the cable — the commonest cause of a short in a set that worked last year.
10. Route cables where nobody will trip.Not across a path, a doorway or a step. Where a cable must cross, use a proper cover, and keep connections up off the ground and out of standing water.
11. Use a timer and switch off overnight.Lights left running unattended for weeks is where faults become fires. A timer handles it and saves electricity.
12. Check the tree lights against the tree.LED sets run cool and are far better against dry foliage than old filament sets. Never use real candles on a tree, and keep any lights away from the trunk where they touch drying needles.
13. Store them properly for next year.Wound on a reel or a piece of card, dry, in a box rather than loose in a bag. Most sets that fail were damaged in storage rather than in use.

Tips

• Photograph the arrangement before taking it down. Next December you will not remember which set went where.
• LED sets use a fraction of the electricity and run cool, which matters both for the bill and for anything they touch.
• Do the outdoor lights on a dry, still, bright day in late November rather than in the dark in December. It is a completely different job.

Common mistakes

• Using indoor lights outdoors — They are not sealed against water. Moisture in a fitting or connector is an electrocution risk, not just a fault.
• Reaching sideways from a ladder — It is what tips ladders over, and falls from height are the most common serious Christmas injury. Climb down and move it.

If it doesn't work

Questions people ask