Before you even buy your first light, make a plan. I know, it seems far more fun to just buy some and hang them, but you will save yourself plenty of time and money if you take a little bit of time to plan. Grab a notepad, a pencil, and a tape measure. Sketch out the areas of your home where you want to add lights and decorations. Add some symbols for what type of lights you want where. Now measure those areas, yes, all of them. Also measure the distance to the nearest electrical outlet for your extension cord(s).
Calculate Power Wattage for Christmas Lights
If you are planning on going big, and I mean National Lampoon big, you will need to make sure your outlets can handle to wattage your lights will be using. If you pull too many watts, your breaker will flip and it won't be very bright. If you have this problem, there are some choices. LED lights use a whole lot less power, but they cost more. You could have an electrician add another outlet with its own fuse. You could also run a long extension cord to a different outdoor outlet if it is on a different fuse.
General rule for maximum number of strands to connect:
LED can connect up to 25.
Incandescent can connect between 3 to 6.
Math to Calculate Wattage
Wattage of the bulb x Number of sockets / 115 = Total Amps