(Radio Iowa) – With Thanksgiving behind us now, some Iowans started decorating their houses for Christmas this afternoon, though others may wait until December to start decking the halls. Andrea Vaspis, public education director for the National Fire Protection Association, says those colorful lights can be a beautiful accent to your house, but they can also pose a serious fire hazard. “When you’re going to be decorating outside, make sure the lights that you use are approved by a testing laboratory and that they’re rated for outdoor use,” Vaspis says. “That is really critical.”

Putting lights outside that are supposed to be for indoor use only could quickly lead to an electrical short — and a fire. If you’re trying to obtain a Clark Griswold-level of outdoor decoration perfection, she warns, it can be easy to overdo it. “A general rule of thumb is to not plug in more than three strands at a time, follow the manufacturer’s recommendations on the box,” Vaspis says. “If you’re opening your tub of old lights and trying to pull them out and see what you have and if anything is frayed or old, it’s time to get rid of it.”

For many Iowans, it’s simply not the holidays if the fragrance of fresh pine isn’t wafting throughout the house, but if you have a “real” tree, it’s important that your electric lights are safe. “For the indoor lighting, make sure that what you’re using is not overloaded in a circuit with a number of other items,” Vaspis says. “Make sure that if you’re putting those lights on a Christmas tree, that the Christmas tree is in good shape, that it’s watered so that the lighting doesn’t cause a fire.”

An association study finds electrical distribution or lighting equipment was involved in more than two of every five (44%) home Christmas tree fires.