Circuit Overload from Christmas Lights: How to Avoid “Pulling a Griswold”

Christmas lights are a popular way to add sparkle and color to the holiday season. Get too carried away, however, and you could end up like Clark Griswold—overloading the circuit for the entire city. Okay, maybe not that extreme. But installing holiday lights without any thought for the electrical load or your circuit’s current rating could trigger your circuit breaker. Here, we’ve answered some of the most common questions about holiday lights to help you deck the halls safely and prevent circuit overload from Christmas lights.

What kind of holiday lights should I buy?

Christmas lights are available in a variety of colors, sizes, styles, and wattages. LED Christmas lights come in just as wide a selection of colors and styles as standard incandescent lights, but they use only 20% the amount of energy as incandescent strands. Not only will using LED Christmas lights lower your chances of short-circuiting your tree, but they’ll save you money on your December energy bill as well. The cost of running incandescent lights can be up to 90x that of LED lights!

So how many strands of Christmas lights can I plug into one outlet?

Hint: The answer is not 250 strands or 25,000 individual lights. Sorry, Clark.

The correct answer depends on three things: the wattage of your lights, the amperage of your circuit, and how many outlets feed into one circuit. You’ll have to do some simple math in order to determine how many lights you can safely plug into your home’s outlets.

While wattage can vary amongst different strands, most Christmas lights operate at 120 volts. To calculate the amperage of your strands, multiply the wattage by 120.

Next, to determine how many strands you can plug into a single circuit, use this equation to work backward:

# of strands = circuit amperage ÷ strand amperage

When you’re doing your calculations, don’t forget to factor in that you may have connected multiple strands of lights together—which multiplies the total amperage, leading to our next commonly asked question.

To figure out how many strands you can plug into one single outlet, reference your electrical panel to identify which outlets feed into the same circuit. Overloading any one of these outlets will overload the circuit, as will a cumulative overload across all the outlets on the circuit.

One final note: Don’t forget to factor in whether you’re running anything else off that same circuit, such as floor lamps or a TV that may be on the other side of the room. These additional electrical loads will impact how many Christmas lights you can plug into one circuit.

How many strands of lights can you connect without causing circuit overload from Christmas lights?

So glad you asked! Many people like to connect multiple strands of Christmas lights in order to cover their entire Christmas tree or large sections of their house exterior. That’s all well and good as long as you make sure to account for those connections when you’re calculating the electrical capacity of your outlet. If you’ve connected six strands of 20 watt lights together, you’re really feeding a total of 120 watts into the outlet. 

How many outlets should I use to plug Christmas lights into?

It may seem most efficient to string your strands of lights end-to-end and then just plug the final strand neatly into the outlet. However, if possible, it’s better to distribute the strands between several different outlets in order to reduce the electrical load placed on any one outlet and avoid circuit overload from Christmas lights.

Even better, plug your Christmas lights into surge-protected power strips rather than outlets. These devices are designed to protect your home appliances from damage from an electrical surge. While your circuit breaker will help to stop an influx of power once detected (and thereby prevent electrical fires from overheated wires) a surge protector gives you an extra layer of defense by protecting any appliances connected to the circuit from damage caused by voltage spikes. Both occurrences can be caused by overloading your circuit.

The reality is, unless you pull a Griswold, you’re probably not in danger of circuit overload from Christmas lights. Most residential circuits can carry 15 or 20 amps, which means you would need to plug at least 90 strands of LED lights into a single circuit before you reach the tripping point. However, it is still good to be aware of how the electrical load you’re putting on your outlets.

National Lampoon Christmas Vacation christmas lights circuit overload
“Pulling a Griswold” = overloading the entire city’s circuit 

RELATED: Holiday Lights Safety Tips: Preventing Fire and Electrical Hazards

One thought on “Circuit Overload from Christmas Lights: How to Avoid “Pulling a Griswold”

  1. Thank you for the great tips on hanging Christmas lights! Although we all want to express our inner Clark Griswold, I’d rather not cause circuit overload or other electrical problems by hanging my lights incorrectly. I’ll be sure to use surge protected power strips and not plug in too many lights on the same circuit.

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