There are two parts to the “How many lights” question – the number of lights strings that can be connected together, and the number of light strings that can be on a single circuit. Before I go too far please remember that I’m not an electrician so if your house burns down because you followed my advice, don’t sue me.
How many lights can be in a single string?
Incandescent (old-school lights): The “rule of 3” is generally applied to incandescent bulbs. You can plug 3 strings in series (end-to-end) safely – generally this is true regardless of the number of bulbs per string (strings range from 25 to 200 bulbs) if the strings were manufactured after 2008. You can also plug the strings in stacks of up to 3 (the plug at the beginning of a string allows you to plug another string into the back of that plug). So, you can have 3 series’ starting from the same location, with 3 strings in each, for a total of 9 strings.
With LED lights the number of lights you can string together is much larger – generally the rule with strings manufactured in the last 3 years is up to 73 sets per series! Personally, I don’t generally go that far with a single series – I generally limit it to about 25-30 per series.
How many lights can be on a circuit?
As a caveat, the math below assumes that there’s no other load on the circuit (i.e. there’s nothing else using it). Because it’s outdoor receptacle, it’s definitely possible it’s on a circuit with other things (outdoor lighting or just another random circuit in the house). You may want to find the breaker, turn it off and see what loses power so you have at least a rough idea of what else is using that circuit.
Receptacle circuits run on 120 volts and are either 15 or 20 amps. You can usually tell a 20a circuit by the plugs – a 20a will have an extra horizontal slot along one of the two non-ground prongs. For safety’s sake, we’ll assume your circuit is 15 amp.
To calculate the number of strings your plug can power you need to determine how many watts the circuit can support. To calculate the number of watts supported, multiply the amperage by the voltage, i.e. 120 x 15, or 1800 watts. However, it’s a generally held convention that circuits should never be more than 80% loaded so we need to reduce that to 80% load – 1800 watts x .8, or 1440 watts.
Now you just need to figure out how much wattage each of your light sets requires. While every product is a little different, here are some good base values you can start with:
- 50 Incandescent mini – 16w
- 100 Incandescent mini – 20w
- 150 Incandescent mini – 40w
- 200 Incandescent mini – 60w
- 50-70 LED Strings – 2.6w
So, if you were using 100 incandescent mini light strings you could have about 36 strings (1440 watts / 20 watts) whereas with LED lights you can have about 550 strings (1440 / 2.6 watts)!
Hopefully that helps! The key is to watch your total load on the circuit and to keep your string series no longer than the manufacturer’s recommendations.
FAQs
You can typically connect 8 to 10 times more LED light strings together end to end while only using one plug outlet. Most traditional Christmas mini lights allow you to connect only 4 or 5 sets end to end, but with many LED mini light strings you can connect 40 to 50+ together depending on the light count.
How many lights can you connect together? ›
So, maximum connectivity is calculated by dividing 210 watts by the number of total watts required by the light string you are considering. For example if your light string is rated at 20 watts, then you can run a maximum of 10 strings together in series.
How many patio string lights can you connect together? ›
If your circuit is 15 amps, this means you can only use a total of 1440 watts. 1440/100 = 14.4. Therefore, your circuit can only handle 14 incandescent strings connected together. On the other hand, if the average LED string set uses 10 watts, then 1440/10 = 144.
How many LED lights are on one outlet? ›
It is the number of amps the circuit can handle and the watts each bulb puts out. If you have a 15 amp circuit in a 120v system and running 5 watt LED's then you can run 360 lights on it. If you have 300 watt bulbs then you can run 6 bulbs.
How many strip lights can be connected together? ›
Up to 10 LED strips can be connected in sequence by simply connecting the output of one LED strip to the input of the next LED strip. Each 9.8 foot 5V LED strip draws approximately 2A, so the total current for 10 LED strips is 10 * 2 = 20A, which is within the safe range of most standard power supplies.
How many extension cords can you use for Christmas lights? ›
A good rule of thumb is not to exceed 1000 watts on a single household breaker. (Note that's breaker not outlet. Multiple outlets can connect to a single breaker so keep that in mind.) So if your light strings are rated at 40 watts per string, you can run a maximum of 25 strings of that rating on one breaker.
How many watts are 100 Christmas lights? ›
So, how much electricity do Christmas lights use? Your display size and choice of bulbs, whether incandescent or LED, will influence your energy bill the most. For example, a 100-count string of incandescent mini lights runs at 40 watts, while a 70 count of 5mm Wide Angle LEDs is approximately 4.8 watts total.
How to calculate how many Christmas lights you need for a house? ›
When decorating your house eaves, a simple rule is to start with at least 60 feet of string lights. Add another 10 to 12 feet for every awning you plan to light. If you have the time and patience, you can measure your eaves and awnings with measuring tape to get the most precise, necessary length of string lights.
What happens if you connect too many string lights? ›
In modern homes, when a circuit is overloaded with Christmas lights (or anything else, like a hairdryer), then the circuit breaker trips, causing the power to go out from anything on that circuit. All you need to do is move a few lights to a different breaker, then locate the breaker that tripped and reset it.
How do you connect multiple lights? ›
A daisy chain connects multiple light fixtures to the same circuit. It's useful for recessed lighting, illuminating rooms, and connecting lights to the same switch. To start, always turn off all the electricity and confirm that no current is flowing to the room.
No more than 2400 Watts worth of lights, on a 120VAC circuit. So that's twenty-four 100W lights, if you run a dedicated 20A circuit. Most rooms will have no use for so many lights, which is why lighting circuits are usually 15A.
How many lights can I plug in together? ›
Divide 210 by the number of watts each string uses, and this will give you your number of strings you can successfully daisy-chain per outlet. For a 20-watt strand, that's 10.5 string lights connected in series.
How many things can be plugged into one outlet? ›
As per guidelines, it is considered safe to plug two or three devices at once into a single outlet. Keep in mind that the total wattage of all connected devices should not exceed the capacity of the outlet. The type of devices you intend on plugging in also plays an important role.
How many sets of lights can you connect? ›
If you are using LED bulbs that only use 1 watt and have a strand with 24 bulbs you can connect up to 45 sets (24 X 45 = 1080). However, if your bulb wattage is 40 watts you can only connect one (40 x 24 = 960).
How do people plug in so many Christmas lights? ›
Use Extension Cords
Extension cords are a staple in any Christmas light enthusiast's toolkit. Discreetly run them from an outlet to the item in need of lighting. They can often be placed behind bushes or pillars, or along walls.
Can you run two lights off one plug? ›
share a common plug/switch? The lights will always be on together so makes sense to join them :) to be modular, it's best for each to have its own 75p plug fused at 1Amp, and both would share a wall socket via a 2- or 3-way adaptor.
How many strings of Christmas lights are safe? ›
Keep it to 3 strands
The Electrical Safety Foundation International recommends connecting no more than three strings of incandescent lights together. If you're using LEDs, most UL-labeled lights will tell you on the package how many strings of lights you can safely string together.
