How to cut and connect LED strip light ?

LED strip lights are commonly used for decoration accent lighting in home, outdoor architectural buildings and landscape lighting.

There are a lot of users having questions about how to cut LED strip lights and how to connect / join them or reconnect them to a desired length, so today, I’d like to share our knowledge about this product, hope this article is helpful for you.

Before we extend to that point, I would like to ask you one question, what kind of LED strip light do you need or how do you choose LED strip light ?

There are two kinds of LED strip lights in markets, one is low voltage 12V 24V DC version, and the other is 120V AC version.

How to make a selection between DC and AC voltage ?

In summary, if it is small decoration lighting project like in the under cabinet, book shelf or kitchen back lighting without too long run, it is better to go 12 volt or 24 volt.

However, big project like outdoor deck lighting, trail lighting, cove lighting, hand rail lighting or task lighting, 120V LED strip lighting is better selection.

Low voltage LED strip lights requires an adapter, which is needed to transfer alternative current(AC) 120VAC to direct current 12VDC or 24DC, and maximum load power cannot exceed the adapter’s supported wattage, you need to calculate the total power of the strip light and buy a proper watt of adapter.

e.g. if the total watt of the LED strip light is 5mx9.6W/m=48W, you need to spare at least 20% headroom, that is 9.6W(=48W*20%), then you need to buy a 58W(57.6W=48W+9.6W) or higher.

Usually, the running length of the LED strips is quite limited(1m-10m), longest only 32.8 feet(10m), 5m in a roll is commonly seen in the market, because the further the LEDs from the power supply, the lower electrical current in the system, if the current is too low, the LED cannot light up.

Below is the Physical math equation, you can get full understand what I mean.

U=I(R1+R2+……..+Rn) , I = U/(R1+R2+…..+Rn)

Therefore, people often install it parallel, and thus, requiring a lot of connectors.

How do you cut the 12V or 24V LED strip light ? and it is safe ?

Yes, cutting the strip is quite safe, as 12V 24V is low voltage line, no danger to human.

For 12V LED strips, it allows you to cut it by every 3 LEDs, while 24V by every 6 LEDs, which is considered a “functional unit” in the LED strips.

12 volt LED strip light
24 volt LED strip light

As you can see, many cut points marked on the strip, you can use a pair of sharp scissors cut down the LED strip light at the given cut lines or cuttable mark.  

And by end of each functional unit, there are copper dots which allows to solder external wires to power supply or control lines.

If you cut wrongly, just the damaged functional unit doesn’t work, it doesn’t affect the other units, so don’t be scared.

Step 1: Measure the length you need and find the nearest cut line to your desired length.

Step 2:  Use a pair of scissors to cut the LED strip lights directly

cut point on LED strip light

How to cut 110V 120W LED strip light ?

Some high voltage 120v LED strip light in market is not cuttable, so you need to check with the seller before you buy it.

If the LED strip lights can be cut, you need to find the transparent gap and use a sharp scissor to cut it according to your length requirement, in general, high voltage light strip can be cut every one meter.

Secondly, we need to figure out if you need IP65 rated waterproof LED strip light or non-waterproof version.

difference between waterproof and non-waterproof LED tape light

Waterproof LED strip lights is wrapped with silicone resin material that keep the LED components from dust and water or moisture. If the LED flex strip light is exposed to water like in the bathroom, kitchen or outside working spaces, taking waterproof version is a must-to-go choice, although it is a little expensive.

Thirdly, what kind of light color you prefer ? RGB mix, single color like red, blue, green, yellow or white (including warm white, neutral white and cool white from 3000K-6000K)?

RGB multicolor is a better option if you want more color conbination and color effects, but don’t forget to use a 3 channel controller.

Fourthly, you need to have an idea on how many lumens output for your DIY decoration project.

And this is often calculated by lumens per meter, which is determined by the LED quantity per meter. e.g. high density LED strip light have more LED chips in each set area, if high density is 3 LEDs in every 2 inches, standard density 3 LEDs every 4 inches, usually 60LEDs/Meter for high density LED strip whereas 30LEDs/Meter for standard density LED strips.

Therefore, if you demands for high lumen output, go high density LED light strips.

Below is a lumen output guide for different application.

Accent lighting 300-900lm/m < under cabinet lighting(500-1000lm/M) < task lighting(1000-1300lm/M) < bedroom cove lighting (600-1500lm/M)

How to Install 12V 24V LED strip light ?

There is usually 3M adhesive tape at the backing of the light strips, after you peel it off, it can be adhered and mounted on any smooth flat surface like the wood, steel under cabinets, bookshelf etc.

Step 1: clean the surface of the working space and let it dry and move to next step.

If the surface has dust or dots, you need to clean them up use a rug and have it dried before moving forward.

clean under cabinet before installing LED light strip

Step 2: unpack & unroll the LED strip lights, cut the light strip to lengths you measured at the cuttable mark.

Step 3: peel the adhesive tape off and stick to the surface, make sure to use your hand to press firmly to squeeze the air bubbles out.

3M adhesive tape on back of LED light strip

Step 4: connect the LED strip light to the controller and adapter, plug the adapter to the main power and turn on the light.

how to connect LED strip light

How to install 120V LED strip light ?

As mentioned earlier, 120 volt LED strip light can be made very long, e.g.10m, 15m, 20m, 25m or 100m is quite common in market.

Step 1: take the LED strips out of the package and unroll it loosen.  

how to install 120v LED strip light

Step 2: Place the strips on the surface you want and use a clip to fix it. We recommend to use one on every 3ft, and remember don’t clip over the LED chips.

how to install 110v LED light strips

Step 3: cut the LED strip light at the transparent gap and use a proper pin to connect with the controller and plug the end cap into the strip light in case leakage of electricity.

how to connect 120v LED tape light

Step 4: Plug into the main power and play.

120v LED strip light plug