1.  Make sure your receptacles are ground-fault protected.  If it snows or rains on your outdoor lights, you don't want to risk electical shock hazards by plugging them into nonprotected elecrricity sources.  Look to see whether your outlets have "reset" buttons on them, which means they are GFI - protected. "If there's any question, a professional can test your outlets."  To further protect your plugs from rain, use an outlet with an in-use cover that can be closed after you plug in item, and put electric tape around the connections between extension cords, he adds.

2.  Lean troward LED lights.  The newer ones use much lower wattage per amp then traditional incandescent Christmas lights, so you can get more lights on your home without the risk of overloading a circuit.

3.  Loading together too many pings on one adapter increases your risk of heat buildup at the connections, which can either trip the breaker or start a fire, especially with older homes.  Instead, you should use multiple outlets so that the electrical current is distributed appropriately.

4.  Holiday MacGyvers might be tempted to drill through walls to pass extension cords from one room to the next, but this is never appropriate. "Everything in the electrrical industrial industry has a UL listing (underwriters lab), but if you're using an elecrrical device for something that hasn't been UL-tested, you're putting yourself at risk.  Extension cords are not designed to pass through or up walls."

5.  If a package of Christmas lights indicates that they are for indoor use only, heed that advice.  Same goes for extension cords - do not use indoor extension cords in your yard.