I need some help with the wiring for LED lights I'm placing in my crown molding and under cabinets.

The power supply and controller boxes will be placed on top of my kitchen cabinets at the start of the molding. From there, I will need six 5m (16.4') strips running almost 100' total.

I am using:


  1. To avoid color changing due to low voltage, I know I must inject power from the supply to each LED strip. My question is, do I need to inject power to each end of each strip or just the beginning of each strip?
  2. Do I need to run dedicated wires from the power supply to each injection point?
  3. What gauge wire do I need to use?

Any input is greatly appreciated. Thanks all!

  • \$\begingroup\$ Just got my LEDs, need to head to the store for power lines. Dying to get this project finished..... \$\endgroup\$ Mar 8, 2021 at 21:32
  • \$\begingroup\$ Wiring is depended of brightness level you gonna apply. One ship is consume 60mA at full brightness but 1mA at minimum brightness. I suggest you to experiment with strips before installing and measure real consumption. \$\endgroup\$
    – user263983
    Mar 8, 2021 at 22:54
  • \$\begingroup\$ @user263983 thanks for the input! I will definitely test things out before installing, just hoping to not spend too much on wires I don't need. Thank you. \$\endgroup\$ Mar 8, 2021 at 22:58
  • 1
    \$\begingroup\$ Consider using more than one 12V supply and arranging your longer runs at line voltage. If you use different sizes and lengths of wire for 12V runs with so much wattage you're begging for brightness balancing problems. To avoid this the best way is to use wire large enough that volt drop is negligible. This may be a problem for you. If you can't follow that plan, next best thing is to roughly balance the resistances so your modules get similar volt drop. As a further note, for daisy chains where volt drop is an issue you can help balance the drop each LED sees by attaching the positive \$\endgroup\$
    – K H
    Mar 9, 2021 at 2:18
  • 1
    \$\begingroup\$ lead to one end of the strip and the negative lead to the other end. This can increase overall wire length if you don't have a good layout plan. \$\endgroup\$
    – K H
    Mar 9, 2021 at 2:19

1 Answer 1


Ideally you would inject power every 2.5 m or 5 m. This is to bypass the FPC strips' high resistance. Which is also why ideally you would run dedicated wires. But having a thick wire run in parallel does work as well. Which leads to your 3rd question, the gauge required depends on the current you are carrying, the voltage that is being used and the acceptable voltage drop. The smaller the gauge the thicker the wire and the less resistance you have to worry about. Google for a voltage drop calculator.

  • \$\begingroup\$ Thank you for the information. I believe I need 10awg wire for the longest runs, but I'm hoping someone can confirm using the product information provided. \$\endgroup\$ Mar 8, 2021 at 21:52
  • \$\begingroup\$ You haven't provided how long the power supply to the strip is or how much of the strip you are using. \$\endgroup\$
    – Passerby
    Mar 8, 2021 at 22:09
  • \$\begingroup\$ I updated the question but I will have 6 strips running close to 100' total. \$\endgroup\$ Mar 8, 2021 at 22:17
  • \$\begingroup\$ If my numbers are correct, I need a 16 gauge wire for the 98.4' run, but the rest I can use an 18 gauge. Is that correct? \$\endgroup\$ Mar 8, 2021 at 23:01
  • \$\begingroup\$ @jacob if you wire it in a star layout instead of sequential this all changes. \$\endgroup\$
    – Passerby
    Mar 9, 2021 at 0:19

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