Choose Christmas lights that have been tested and deemed safe by a reputable testing laboratory. This will be noted on the packaging when you buy them.
Try to use the cooler-burning “mini” Christmas lights as opposed to the traditional larger bulbs. The older styles burn much hotter.
Only use Christmas lights that have fuses in the plugs.
Inspect each set of Christmas lights – old or new – for damage. Return or throw out any set with cracked or broken sockets, frayed or bare wires, or loose connections.
Replace burned out bulbs promptly with bulbs of the same wattage.
Never hang Christmas lights on a metal tree. The tree can become charged with electricity and shock someone. The tree can also short out the Christmas lights and cause a fire.
When hanging Christmas lights outdoors use outdoor Christmas lights. The packaging will note whether the lights can be used indoors, outdoors, or both.
All outdoor electrical decorations should be plugged into a ground-fault circuit interrupter (GFCI). You can buy portable units for outdoor use, or you can have them permanently installed by an electrician.
Use extension cords properly. Outdoor cords can be used inside or outside. Do not overload extension cords – they can get hot enough to burn.
Stay away from powerlines or feeder lines (these go from the pole to the house).
Secure outside Christmas lights with insulated holders (never use tacks or nails) or run strings of lights through hooks.
When you leave or go to bed at night, turn off your Christmas lights.
Never pull on a string of Christmas lights, it stresses the cords and can lead to fraying. Store Christmas lights loosely wrapped for the same reason.