About the choice of wiring in LED lighting installations About the choice of wiring in LED lighting installations
Wires have electrical resistance. There is a flow through, we get voltage drop across the wire.
The voltage drop over the wire times the current flow through the wire give a power dissipation into the wire.
So the wire will warm up until an equilibrium is established between the power heat and the cooling to its surroundings.
The greater the temperature difference with the surroundings, the faster heat dissipation.
For the heat technical reasons, the current flow through the wiring depend on a number of parameters:
  • the maximal current specified by the manufacturer of the wire (specication, more current, more voltage drop)
  • the resistance of the wire (thinner wire, higher resistance, more voltage drop)
  • the temperature that the wire may have (wire with silicone insulation may be much hotter than wire with PVC insulation)
  • the possibility of cooling to its surroundings (is the wire free, or exist the wire in a PVC pipe)
Sometimes it’s not the heat of the wire for the determining factor for the selected wire diameter.
In low voltage LED lighting installations also the voltage drop is a point of interest.
When we lose a few volts in a long cable, it a sufficiently thick wire may not have a heat problem.
Because the voltage drop at the end of the cable, the current through te voltage-controlled LED lighting can be significantly reduced.

In RGB LED strip for example, there are three LED’s connected in serial per color, each color with its own ballast resistor for the current limitation.
Green and blue LEDs have a threshold voltage of about 3.3 volts.
Below this threshold voltage, the amount of light lowered drastically. In a further few tenths volts lower, there is virtually no light emitted anymore.
Below 9V the green and blue color will be off in a 12V segment with three RGB LEDs.
However, red LEDs have a threshold voltage of about 1.9 volts.
Below 5V the red color will be off in a 12V segment with three RGB LEDs.
Thus the 12V preset white will look all pretty pink at 10V, and a yellow color at 12V will be look already quite orange at 10V.
This voltage drop exist also over the copper tracks within the LED strip, and is visible when the length of the LED strip to long and only one side is fed.
At the beginning of the LED strip all current flows through relatively thin copper tracks, where in the + track the current flows of all three colors.

Through all these above factors, it is important to calculate the total power consumption of the LED lighting installation and make a right decision for the wiring topology.
For advice on this please contact Ledtuning.nl.


Conversion table - American Wire Gauge - Diameter (mm) - Area (mm²)

AWG (N°)Diameter (mm)Area (mm²)AWG (N°)Diameter (mm)Area (mm²)
0000 11.684 107 19 0.912 0.653
000 10.404 85.0 20 0.812 0.518
00 9.266 67.4 21 0.723 0.410
0 8.252 53.5 22 0.644 0.326
1 7.348 42.4 23 0.573 0.258
2 6.544 33.6 24 0.511 0.205
3 5.827 26.7 25 0.455 0.162
4 5.189 21.2 26 0.455 0.129
5 4.621 16.8 27 0.361 0.102
6 4.115 13.3 28 0.321 0.0810
7 3.665 10.5 29 0.286 0.0642
8 3.264 8.37 30 0.255 0.0509
9 2.906 6.63 31 0.227 0.0404
10 2.588 5.26 32 0.202 0.0320
11 2.305 4.17 33 0.180 0.0254
12 2.053 3.31 34 0.160 0.0201
13 1.828 2.62 35 0.143 0.0160
14 1.628 2.08 36 0.127 0.0127
15 1.450 1.65 37 0.113 0.0100
16 1.291 1.31 38 0.101 0.00797
17 1.150 1.04 39 0.0897 0.00632
18 1.024 0.823 40 0.0799 0.00501
Stripped wire
Stripped wire
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