When one bulb in a string stops working, the other bulbs shine brighter and become hotter. Turn off light strings and electric candle sets at night. This reduces the risk of fire.
Light strings are made up of a number of small lamps. If one or more lamps stop working, the light is designed to ensure that the others stay on, but with increased brightness. This can result in the lamps becoming too hot. This can then cause Christmas decorations and other flammable material nearby to catch fire. Always turn off light strings at night or when you go out.
If you want to hang decorative lights outside, you must use lighting that's suitable for outdoor use. Never run cables over door thresholds or through windows. The frames can pinch and damage them.
In electric candle sets that contain several bulbs, such as Advent candle sets, the lamps are usually designed so that they all go out if one lamp stops working. If the lamps are shining at different brightnesses, some of the lamps may become too hot. Change any bulbs that are shining with a different brightness to the others