Introduction: How to Install Under Counter LED Strip Lights With Dimmer

By Flexfire LEDs Website
About: Flexfire LEDs is famous for creating unique interior and exterior lighting experiences by manufacturing and distributing our powerful linear LED strip lighting products. Trusted by the top design and construct…

A common question for those who are new to LEDs is "how to install LED strip lights under counters and cabinets." The process is easy and has a very similar set of steps in both cases. Even if you do not have advanced knowledge of electronics, the project can be done as a DIY project — although it's always a good idea to consult an electrician first before working with electricity.

We recently installed dimmable under counter LED lighting at a local cafe. Read on to learn exactly how it was done and gain some knowledge for your next home or commercial business LED strip light installation.

See the Before/ After photos above.

Step 1: Pre Installation: Selecting the Lights and Power Supply

Supplies Used:

  • 2 reels of ColorBright Warm White strip lighting*
  • 100w Mean Well 12v Power Supply unit*
  • Cerrowire extension
  • Strip-to-strip solderless connector
  • Strip-to-strip "no wire" solderless connector
  • LED strip Dimmer
  • Measuring tape
  • Wire strippers
  • Sharp scissors
  • 4 wire nuts
  • 3M Command Hanging Strips
  • Black electrical tape

* LED strip Lights: You first must choose which color and brightness is needed for the under counter LED strip light installation. We selected ColorBright Warm White LED strip lights because the color matched the existing lighting colors in the cafe (3000k color temperature). Warm color temperatures are great for creating a comfortable atmosphere and promoting feelings of relaxation.

* Power supply: We have created a chart to help figure out which power unit you will need for your project. View the chart here. We used under two reels (around 28 feet) for this installation. The ColorBright strips use 2.9W per foot. So around 81W in total. Typically, you need to choose a power supply with an extra 20% capacity than the load you are requiring for various reasons, so we selected a 100W 12V Mean Well Power Supply unit.

Step 2: Double Check Your Lights Before Cutting or Installing

When installing LED strip lighting under your counters, cabinets, or inside coves, it is very important that you test the LED lights before any installation. Follow the steps below before you cut any of the lights or attach them to any surface.

  1. Lay out all the products to create a mock installation to make sure you have all the supplies necessary
  2. Unroll the LED strip lights from the plastic reel
  3. Attach the uncut lights to the power supply and turn on the power supply
  4. The strips should light up. If they do not, please check your connections
  5. Ask yourself - "Are these bright enough?", "Will I need a dimmer", "Is the color perfect for my application?", "Are all the LEDs lighting up and functioning properly?"
  6. When the lights are functioning properly and you are sure you have selected the correct color temperature and brightness for you project, proceed to step two.

If they are not functioning as expected, there is usually a simple connection error.

Step 3: Take Measurements and Make Cuts

Measure the length of the counters where the LED strips are to be installed. Before starting the installation process, take careful measurements to determine how many feet of strips will be necessary. Then cut the strips to length with sharp scissors in order to prepare them for the quick installation process ahead.

Note: LED strips can only be cut along the clearly marked lines that are evenly spaced. On this LED strip, the cut lines are after every three diodes all the way down the strip.

Step 4: Preparing the Strip-to-Power Connection

To attach the lights to the dimmer and power supply, we need to add a length of low voltage extension wire to the end of the first run of LED lights.

Once the low voltage wire is cut to length, strip an inch of wire insulation from the end of the wires coming off the LED strip and an inch off the low voltage extension wire. From there, wrap the exposed wires of the positive/negative cables together, using wire nuts to secure the connection.

Step 5: Connecting Two Lengths of LED Strips With Strip-to-strip Connector

In the photo of the completed installation, you will notice a 90-degree angle at the corner of the bar. To go around this corner we had to connect the two cut sections of LED strip lights. To do this, we used a strip-to-strip solderless connector to connect the first run of lights to the second.

The next step is to attach the solderless connector to the ColorBright LED strip. To do that just peel back a half inch of the tape cover and the 3M tape on the back, exposing enough space for a connection.

Take the solderless connector and pull out the mounting tray to prepare for attachment. Each solderless connector has two sides. To make sure you have it arranged correctly, ensure that the wider of the white sides faces upward.

Next, GENTLY secure the locking tray back in place over the end of the flexible LED strip. Be gentle and make sure the mounting tray is securely closed, or the lights will not work. Find the positive (+) and negative (-) sides that are marked on the LED strip and note which wires coming off the solderless connectors will carry the negative and positive charges.

Repeat the process to attach the other end of the strip-to-strip connector to the second run of lights.

*NOTE: Red and black wire colors are not always correct indicators of positive and negative. Please look for the positive and negative markings on the strip and associate the wire on that side of the strip to indicate polarity.

Step 6: Combining Strips With Strip-to-Strip "no Wire" Connectors

For runs longer than 16 feet, we need to connect two separate runs of LED strips. There is no for wire in the middle of the connectors, as we wanted the transition seamless, so we used strip-to-strip ("no wire") connectors to combine the two lengths.

First, cut the strip at a designated line. Peel back the cover as you did to attach the strip-to-strip connector in step 4. Then clip into place the two lengths of strips using the strip-to-strip "no wire" connector, again taking care to create a firm point of contact between the strips and ensuring the positive/negative sides are aligned correctly.

Step 7: Test the Strip (IMPORTANT)!

Use a 2-way terminal block or wire nuts to temporarily connect the full length of LED strip lights with the power supply. If everything is wired correctly, the lights should switch on when the power supply is plugged in. If they don't come on right away at full brightness, check to see that the connectors are solidly attached and that the negative and positive wires are aligned correctly onto the strip.

Note: For free advice, give Flexfire LEDs a call

Step 8: Install the LED Strips Under the Counter

Wipe down the under surface of the counter and make sure it is clean. The 3M take will stick to most non-porous and flat surfaces. For applications under concrete or very rough material, an adhesive may be used. After wiping the under counter clean, peel back the protective cover over the strip's adhesive backing. Run the strip in a straight line under the counter where you want the lights to shine.

Step 9: Installing the LED Dimmer

To mount the dimmer to the wall, we suggest using 3M Command Hanging Strips. Next, wire the unplugged power supply into the dimmer by running the wires (the black wire goes in the negative (-) slot and the red wire goes into the positive (+) slot) into the bottom housing on the right side labeled "In". Use a flathead screwdriver to secure the connection. Then wire the Cerrowire into the section of the housing labeled "Out", again using the screwdriver to secure the wires into place.

The final result should look something like the mounted LED dimmer as illustrated in the photo.

Step 10: Turn on the Lights!

The last step is the easiest, but also the most fulfilling, part of the whole process. Now all you have to do is plug in the power supply, turn up the dimmer to the brightness level of your choosing, and enjoy your new under counter LED lighting!

How to start your own under cabinet or under counter project:

1. Determine which brand of lights you will need:

There are many different types of strips out there, each with their particular use. Before you start your project, you will need to select the brightness, color, and style of your LEDs. How to choose the best LED strip light for your project

2. Choose a LED lighting kits

LED strip light kits will come with all that you need to complete LED strip light installations. They can be ordered with or without a wall dimmer. Flexfire LEDs can also help build custom kits specifically for your project at no charge! Let us build your custom LED kit for you!