When Christmastime comes, the outdoor lights come out all across the United States. Though these lights look the same as the string lights used to wrap a Christmas tree or decorate the interior of a home, outdoor Christmas lights are made to endure cold winter temperatures and moisture from rain, snow and ice. In order to keep your outdoor Christmas lighting display safe for your home, you should also keep outdoor conditions in mind when wiring your lights.
Find an electrical socket in or around your home where the wires will be out of the way of everyday traffic. Plug in a surge protector or another electrical socket receptacle to the outlet and note the maximum amps recommended for the receptacle.
Run extension cords from the power receptacle. Make sure you get insulated extension cords recommended for use outdoors and plug in only as many extension cords to each the receptacle as the receptacle can handle. For instance, if you have 13-amp extension cords and the power receptacle can handle only 15 amps, you can plug in only one extension cords per receptacle.
Figure out how many Christmas lights you can string together and plug into each extension cord. Calculate the number of lights an extension cord can handle based upon the amperage of the lights. According to All American Christmas Company, light strands with 25 bulbs run between approximately 1.1 and 1.6 amps; strands with 100 bulbs run between roughly 4.5 and 6.4 amps, depending on the type of bulb.
String together only the number of lights that each extension cord can handle to plug into each extension cord. If you have 50-bulb light strands at 2.3 amps apiece, for instance, you can string five strands of lights together to plug into a single 13-amp extension cord.
Before wiring your outdoor Christmas lights, you must know the distance that each cord must reach. To determine this, measure the distance from the electrical socket you want to plug the lights into to each spot in your yard that you want to light. When measuring, run your measurements down walls and across the floor and the ground, and then add a foot to each measurement to ensure you have enough slack in the cord. The amperage of each strand of Christmas lights should be listed on the packaging.