Unfortunately, these holiday lights have been known to overwhelm the electrical systems of homes—and can even lead to dangerous electrical fires. We’d like to address these concerns in this post. We work with both indoor and outdoor lighting in Montclair, NJ and the surrounding areas, so we have plenty of experience when it comes to festive holiday lighting and how to keep safe through the season.

Before you consider putting up a massive set of lights, either indoors or outdoors, ask yourself how old the home’s electrical panel is. This panel is where the incoming current from the grid is split into different circuits (and yes, this includes outdoor power). A panel more than 15 or 20 years old may not be capable of handling the higher demands of modern electrical systems, let alone the addition of holiday lighting. We recommend arranging for a new panel installation with our electricians. If you still have an old fuse box rather than circuit breakers, have the upgrade done ASAP!

Even with the newest electrical panel, too much electrical demand from adding light strings can lead to tripped breakers or even fires. To avoid trouble, find out the safe wattage for the circuits you are going to use for the lights and make sure the lights don’t exceed this.

Each circuit has a total wattage capacity. The safe wattage is about 80% of this. To determine safe wattage, look at the numbers beside the circuit breakers on the panel, which list an amperage. Multiply this number by 120 volts, and then multiply that number by 0.8 (i.e. 80%). This will give you the safe capacity of the circuit. For example, if you find the indoor circuit for where you plan to plug in the tree lights is 20, then the wattage capacity is 2,400 (12 x 120) and the safe wattage is 1,920 (2,400 x 0.8).

Now add up the watts of the lights you want to put onto this circuit. You don’t want to exceed the safe wattage amount. However, if other lights or appliances are using this same circuit, such as lamps or a television or other outdoor lights, you must subtract their wattage from the safe wattage first. Remember to count each string of lights—if you keep adding on more light strings, you’ll eventually trip a circuit breaker and be in the dark.

If anything does go wrong with your electrical panel or other parts of the electrical system due to holiday festive lighting mishaps, please don’t try to make any fixes on your own. This is a fast way to create bigger hazards or give yourself a dangerous high voltage shock. Reach out to our licensed electricians to handle the task.