Below you can read the measurement results of practical examples.
If you buy an RGB LED strip, you will see that a 5-meter roll has about 10 cm of 4-core connecting wire. This wire has a cross-section of 4×0.2mm2.
RGB LED strips consume 6W, 10.8W, or even 14.4W per meter, depending on the type. For example, a 5-meter roll with a nominal consumption of 72W also has a 10 cm long 4×0.2mm2 cross-section connecting wire. One might think that if we want to install RGB lighting in a room, we can run the connection anywhere with such a cross-sectional wire, as long as we don’t exceed 72W consumption. This reasoning is flawed because the longer the wire, the higher its resistance, which means the LED strip will receive less voltage and will shine dimmer. To operate a 5-meter 72W LED strip, you need to ensure 6A at 12V.
The article also addresses the resistance of the LED strip. The farther the LED is from the power connection, the dimmer it will light. This issue is also considered below.
Let’s look at some practical examples:
First test group is a 1-meter long LED strip with 60 pieces of 5050SMD RGB LEDs, manufactured by V-TAC, with a nominal consumption of 10.8W, connected to an 18VA V-TAC adapter without a controller.
- Direct connection from one end results in a consumption of 10.5W. (All measured consumption values include the power supply.)
- Adding a 25cm long RGB splitter results in a consumption of 10.8W.
- Connecting the other end directly results in a consumption of 10.9W.
From this, we can conclude that for such a 1-meter LED strip, the voltage drop across the strip is practically zero, making it unnecessary to connect such a short LED strip from both ends.
Staying with the one-end connection, if we insert a 1-meter long 4×0.2mm2 cross-sectional wire between the adapter and the LED strip (similar to the 10cm long factory connecting wire), the consumption is 10.4W, indicating that this 1-meter wire has practically no adverse effect.
If we insert a 5-meter long 4×0.2mm2 cross-sectional wire between the adapter and the LED strip, the consumption drops to 9.5W. Although this is a 10% performance drop, it is still negligible – if only a 1-meter LED strip installation is required.
So, if we want to operate such a short RGB LED strip, we can confidently connect it from one end and use longer wires (several meters) that are not thinner than the factory connecting wire.
Since installing RGB LED strips for room mood lighting may require 5-10, or even 20-30 meters of LED strips, it is essential to examine the consumption reduction if more LED strips are to be installed.
Let’s examine factory whole 5-meter rolls.
The second test group is a 5-meter long LED strip with 300 pieces of 5050SMD RGB LEDs, manufactured by V-TAC, with a nominal consumption of 54W, connected to a 78VA V-TAC adapter without a controller.
- Direct connection from one end results in a consumption of 36.9W. This is significantly lower than the nominal consumption.
- Adding a 25cm long RGB splitter results in a consumption of 35.0W.
- If we connect the other end directly, the consumption is 45.8W. Yes, the situation is much better, but we rarely want to create an RGB LED strip circle with a 5-meter perimeter. It is more likely that we need to run a 5-meter long 4-core wire along the LED strip to connect the other end.
- In this case, using a 5-meter long 4×0.2mm2 wire, the consumption is 43.6W.
- If someone is dissatisfied and uses a 5-meter long 4×0.75mm2 wire, the consumption is 45.6W. This means that with this cross-section, we have eliminated the performance loss caused by the wire.
But let’s see what happens if an initial 5-meter wire is needed for the one-end connection.
- Using a 4×0.2mm2 wire, the consumption is 28.2W.
- Using a 4×0.75mm2 wire, the consumption is 33.6W.
Using only a 1-meter 4×0.2mm2 wire, the consumption is 33.9W.
Conclusion of the second test group:
It is definitely advisable to connect both ends of the 5-meter roll. In fact, a longer LED strip created from this roll should be designed to provide power input every 2-2.5 meters from both ends to not only approach the nominal consumption of 54W for 5 meters but exceed it. If we really want to operate no more than 5 meters of this LED strip, then a 4×0.2mm2 wire is sufficient. However, if we want to supply power to the entire LED strip from several meters away, it is advisable to use a 4×0.75mm2 wire up to the first power connection.
Third test group involves the installation methods of a 2x5m, i.e., 10-meter long LED strip containing 600 pieces of 5050SMD RGB LEDs manufactured by V-TAC with a nominal consumption of 108W.
- Direct connection from one end results in a consumption of 41.4W. This is a significant shortfall from the nominal consumption.
- Direct connection from both ends results in a consumption of 64.8W. This is still very low. Moreover, to be accurate, we should include a 10-meter 4-core wire for the distant connection.
- Thus, using a 10-meter 4×0.2mm2 wire, the consumption is 55.8W.
- If we want to do it correctly, we need to provide a power input in both directions at least in the middle of the two 5-meter sections. Then, using 2 pieces of 25cm long RGB splitters and 2 pieces of 5-meter long 4×0.2mm2 wires, the consumption is 62.8W.
- If we replace the 5-meter section closer to the power source with a 4×0.75mm2 wire, we see significant improvement: 71.6W.
- In fact, this wire is not 4 times but 5×0.75mm2, so I soldered the 5th wire to the anode, thus achieving 3×0.75mm2 + 1×1.5mm2 cross-section, and the consumption slightly increased to 75W.
The question arises, where is the limit?
The user manual provided with LED strips usually does not specify the required wire cross-section, which causes problems for hobbyists and DIY enthusiasts. However, electricians know this, and several tables can be found on the internet. The strength of the current flowing through the conductor and the material of the conductor determine the minimum cross-section of the wire required. The usage instructions of Pannon LED strips include such a table. According to this:
- For 1 Amp, use a 0.75mm2 wire,
- For 2 Amps, use a 1mm2 wire,
- For 4 Amps, use a 1.5mm2 wire,
- For 6 Amps, use a 2mm2 wire,
- For 9 Amps, use a 2.5mm2 wire.
In this case, when we have a 5-meter, 54-Watt RGB LED strip with a current draw of 1.5 Amps per color channel, it is correct to use a 1mm2 wire for the power connection, while for the distant end connection assuming half the current, 0.75mm2 is sufficient. However, the LED strip will not shine at 54 Watts, because achieving this requires connecting shorter sections from both ends. If we do this every 2-2.5 meters, we can expect good results. However, it is likely that two-end connections every meter using at least 0.75mm2 wires are needed to closely approach the nominal consumption.
Thinking further about the implementation, if such thick wires are required and the RGB splitters, extensions, and connectors are only 0.2mm2, the question arises whether it makes sense to use these elements in a more serious system. It does not make sense because in a 0.75mm2 wiring system, they would only act as bottlenecks. Instead of using connecting wires, it is better to solder 0.75mm2 wires directly to the LED strip, or if those 10cm pieces remain, the use of 0.2mm2 RGB splitters alongside 0.75mm2 wires is completely pointless. Wago removable wire connectors provide a suitable solution. Moreover, it is advisable to forget about adapters, as their 12-Volt output wires are usually 1.5 meters long, with an unknown cross-section, but when considering the insulation, they are always thinner than a 2×0.75mm2. Therefore, use fixed direct current power supplies instead.
Theoretical wiring diagram for creating RGB LED lighting longer than 5 meters with appropriate cross-section wires, double-ended connections, and Wago wire connectors:
Naturally, the implementation becomes more complicated if we want to install so many LED strips that their total power exceeds the controller’s capacity. In this case, a signal amplifier or amplifiers and additional power supplies are necessary. But that is another topic.
Attention! The nominal consumption data refer only to the LED strip, while the measured consumption includes the power supply. The measurements are not certified.