Does this sound familiar: every Christmas you try to plan your lighting, but find yourself asking, "Why do I keep tripping by circuit breaker?" or "Why do I keep blowing fuses?" Perhaps you are wanting to increase your light display this year, or you are trying to calculate ways to save on power during the holiday season. To help answer these questions and plan a display for a stress-free season, we will walk you through the calculations related to power consumption, and address common amperage capacity issues.
The questions we plan to answer in this resource include:
Click here to learn how wattage impacts your electricity bill.
Understanding Christmas light wattage and amp current helps to ensure the best Christmas lights display. Wattage has an impact in every area of Christmas lights from planning to installation. Once you can find out your bulb wattage and understand how amperage affects your project, shopping for Christmas lights and customizing light displays becomes a lot easier.
Watts is a measurement of the amount of energy used. Wattage is typically provided per bulb or string, listed on the bulb or near the UL tags on a string. If wattage is not listed on the stringer or bulb, wattage meters are available for around $10 to calculate draw.
An incandescent mini light bulb will use a significant less amount of watts than a larger C7 bulb, and LED bulbs will typically use 80-90% less than their incandescent counterparts.
When string wattage is not listed but bulb wattage is known, simply multiply bulb wattage by total lights on the string to get total wattage.
Watts are a unit of energy (or power) used, and Amps are how much energy the watts draw. Amp capacity refers to the total Amps that can be supported.
Amp Capacity in a String determines how many bulbs can be used in a single length of wire. This typically applies when stringers and C7 or C9 bulbs are sold separately and lighting is customizable. All stringers and spools at Christmas Lights, Etc list Amp capacity in product specifications.
Staying within 80% of the Amp capacity of a wire ensures Christmas lights stay lit throughout the season.
Amp Capacity in a Circuit determines how many total watts can be plugged into a full circuit, regardless of how many outlets the circuit contains, or outlet extensions are added. Outlets connected to a single circuit share that circuits Amp capacity, so be sure to also take into account other items running of the same circuit, such as household lamps and electronics.
Staying within 80% of the Amp capacity of a circuit ensures the breakers dont trip.
When using prelamped strings, or Christmas light strings where the bulbs are already secured into the sockets, total Amps is usually listed in the UL tag near the total watts. When total Amps is not already provided, first calculate total watts, and then calculate for Amps.
Calculate Amps by dividing total wattage by 120 volts (US household outlets carry 120 volts)
To answer this question, you will need to look at the circuit breaker box.
What you need to know about circuits:
Divide the total wattage of a 15 Amp current (1800 Watts) by the wattage of your Christmas lights. Use only 80-90% of the wattage for best safety practices. View the chart below for amp needs for more common types of light strings:
*Keep in mind other items such as outdoor Christmas decorations and household items may be plugged into outlets on the same circuit. Be sure to calculate for their power draw.
Christmas Lights, Etc follows UL Standards regarding max strings connected, or how many light strings can be plugged together into a single outlet opening. UL listed lights state a maximum of 210 watts can be connected when using 22 gauge wire, and a maximum of 420 watts can be connected when using 20 gauge wiring.
|Mini Lights||Lights Per String||String Watts||Max Strings Connected|
|Standard Mini Lights||50||20.4 watts||10|
|Standard Mini Lights||100||40.8 watts||5|
|Premium Mini Lights||50||20.4 watts||10|
|Premium Mini Lights||100||40.8 watts||5|
|Commercial Mini Lights||100||40.8 watts||10|
|LED Mini Lights|
|LED 5MM Mini Lights||70||4.8 watts||48|
|Commercial LED 5MM Lights||25||2.4 watts||175|
*20 gauge wire is used in commercial sets
We suggest following max sets connected recommendations for best results.
Note how many more LED Christmas lights can be plugged together. LED lights require only a fraction of the power that incandescent lights draw, consistently resulting in the ability to plug more LED lights together.
LED Christmas lights wattage is significantly less than incandescent lights, and bulbs always stay cool to the touch. LED lights save money both in the power bill, and as an investment: with 50,000+ hours average life versus 3,000 for incandescent lights, LEDs can be reused for years. To read more about LEDs and their benefits, check out the LED Christmas Lights Guide.
Yes, timers help in saving power by scheduling exactly how many hours to run Christmas lights. When selecting a timer, be sure to check for Amp capacity. Note that if you choose a 15 Amp timer and use it with a 15 Amp circuit, that circuit can still only support 15 Amps total - the timer does not add Amp capacity to a circuit, it supports Amp capacity of the lights that are plugged into it.
Our stringers and spools use UL Recognized components and meets CSA specifications, allowing longer runs of wire than prelamped strings. It is best practice to draw only 80-90% of the rated capacity. Use the following formula to calculate how many bulbs can be used in a single custom run using stringers or spools:
Just in case you missed it above, here is the formula for determining what amp capacity is needed:
Understand electricity power consumption and how much it would cost to power your house during the Christmas season.
Shop energy efficient LED Christmas lights that use only 10-20% of the energy consumed by incandescent bulbs. Choose from LED mini lights and learn more about the advanced technology.
Learn to wrap trees and bushes with the perfect amount of Christmas light strings. Discover the perfect strings for outdoor Christmas decorating.