It’s Christmastime and people are wondering if their Christmas lights are overloading the circuit. The short answer is probably not, that is if you’re using LED lights.

According to the Department of Energy, LEDs use at least 75% less energy and last 25 times longer than incandescent lighting. They emit very little heat, are more resistant to breakage, and rarely are the cause of overloading a circuit. The downside is the high upfront cost.

While LEDs are better than incandescent lights in nearly every way, incandescent are cheaper to purchase and some people still think they look better than LED lights. There may be something to that.

If you really want to know if your Christmas lights are overloading the circuit and how to prevent it from happening in the first place, continue reading.

What Does the Circuit Breaker Do?

The circuit breaker protects your wires by shutting off power in the event of an electrical overload. If your wiring didn’t have the protection of the service panel, electricity could overload, overheat, and cause a fire.

When your panel is working properly, circuits will be automatically turned off when the circuit becomes overloaded. Keep in mind that one circuit often supplies power to multiple outlets.

Each circuit in your home supplies a certain amount of power, usually 15 or 20 amps, which is 1800 or 2400 watts, respectively. The breakers or fuses should be labeled with the amperage rating.

Try to avoid overloading outlets in general. If you continue to overload your circuit, speak with a professional electrician about having additional circuits installed or replacing your electrical panel with a higher amperage one.

If the circuit breaker is tripping frequently and it’s not from overloading the circuit, there may be a problem with the wiring itself. Contact an electrician right away.

Christmas Light Safety

Remember to check the packaging for how many light strings you can safely string together. Never exceed this limit. Plugging too many light strings together can cause overheating and potentially a fire.

Another big benefit of LEDs is that you can string many lights together without fear. Always follow manufacturer instructions.

How to Prevent Christmas Lights from Overloading the Circuit
How many amps can your circuit handle?

First, you have to determine which circuit or circuits your Christmas lights are plugged into and how many amps each circuit can handle.

You can do this by finding your electrical panel and looking at the label inside of the box. If you can’t find the amperage rating, contact your local electrician.

For continuous loads, multiply the load by 80%

In order to prevent tripped breakers, you want to multiply the circuit’s amperage capacity by .8 (80%). While you can exceed 80% of the rated amperage, there’s a possibility of it tripping the breaker. This is the rule for continuous loads (stays on for more than 3 hours).

Map your circuits (breakers/fuses) to your outlets

Each circuit is controlled by a breaker or fuse. The breakers (or fuses) should be mapped to your home, but if they aren’t, now is a good time to label your electrical panel for future use and convenience.

To determine which breaker is connected to which circuit, flip breakers (or remove fuses) and see which outlets/areas turn off. Get a second person to help with this task. Otherwise, you will be running back and forth to the electrical panel. Learn tips for mapping your electrical panel to the various circuits in your home.

Do the math

Once you know how many amps your outdoor circuit can handle, you will want to add up the power requirements of all of the lights plugged into a single circuit. It’s time for a little math.

You can find out the current requirements of your lights by looking at the packaging (or the product tag on the lights themselves).

If your lights are listed in watts rather than amps, use this simple formula to convert the power requirements into amps. Remember to use 80% of the circuit’s amperage (12 amps instead of 15; 16 amps instead of 20).

Amps = Watts/110

Conversely, you can convert the amperage of your breaker to watts. Simply take the amperage requirements (15 or 20 amps) and multiply it by 110 to determine its wattage capacity.

Watts = Amps x 110

The final step is to compare the power requirements of your lights with the amperage of your circuit.

For instance, if you add up all the lights on your circuit and it comes out to more than 1300 watts, they may overload your circuit. It’s a good idea to do this calculation before going Griswold.

For more safety tips, learn extension cord safety and how to avoid winter electrical problems.


Contact OnTime Service to schedule your next electrical, plumbing, or HVAC appointment at 205-942-1405.

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