In controlled lighting systems, particularly when using popular addressable LED strips based on the WS2812, one of the critical factors for reliable operation is proper electrical wiring design. Specifically, the length of power and signal lines can significantly affect both power stability and data transmission quality.
In this study, we tested various strip connection configurations using a matrix of 1000 LEDs, including parallel and serial connections, signal cable replacements, and relocating power supply units closer to the strips. The goal was to determine the critical cable length limits and identify the most stable installation methods.

Maximum Distance to the LED Strip

When using an 18-meter power and data cable (1 mm² cross-section) to connect to a 1000-LED matrix, a significant voltage drop to 3.5 V is observed. This is the lower operational limit for WS2812 LEDs. The strip loses brightness but continues to display effects without glitches.
Two connection formats were tested: ● The (-) line runs from the power supply unit (PSU), with an additional (-) line from the controller with the DATA signal. ● The (-) line runs from the PSU to the controller, and from there, together with the DATA line, to the LED strip.

Data Transmission Cable Replacement

When using an 18-meter power cable and a 25-meter UTP cable for the DATA and GND lines from the controller to a 1000-LED matrix, no defects were observed in the playback of effects on the matrix. The voltage drops to 3.5 V, which is the minimum operating limit for WS2812 LEDs.
Two connection formats were tested:
● 4x4 configuration – four wires for GND and four for DATA, utilizing all four pairs of the UTP cable.
● 1x1 configuration – a single wire for GND and one for DATA, using just one pair.

Splitting into Two Parallel Segments

When using an 18-meter cable for power, DATA, and GND lines from the controller to two separate 500-LED matrices, no defects were observed in the playback of effects. The voltage drops to 3.5 V, which is the lower operational limit for WS2812 LEDs.

When using an 18-meter power cable and a 25-meter UTP cable for the DATA and GND lines from the controller to two separate 500-LED matrices, no defects were observed in the playback of effects on the matrices. The voltage drops to 3.5 V, which is the minimum operational limit for WS2812 LEDs.

Branching into Two Parallel Segments with Extended Lines to the Segments

A 1-meter 1mm² power cable and a 25-meter UTP cable for the DATA and GND lines were connected from the controller to the branching point, from which an additional 5-meter cable with DATA and GND lines runs to each 500-LED matrix. Everything operates properly, with minimal voltage drop.

Serial Connection of LED Strips

An 18-meter 1mm² power cable was connected to both strips, and a 25-meter UTP cable for the DATA and GND lines was run from the controller to the first 500-LED matrix. Then, a 5-meter cable with DATA and GND lines runs serially from the first to the second matrix.
Two cable configurations were tested:
● Using the 1mm² power cable for both (-) and DATA lines — the second matrix did not work.
● Using one conductor from a single UTP pair for both (-) and DATA — the second matrix did not work.
● Using one conductor from a single UTP pair for DATA only — the second matrix worked but with noticeable defects.
These issues were caused by interference from the (-) line of the matrix. When the power cable was replaced with a shorter one of larger cross-section, the serial connection using a UTP cable with one pair for (-) and DATA started working stably.

Relocating the Power Supply Unit (PSU) as Close as Possible to the LED Strip

A 1-meter 1mm² power cable and a 25-meter UTP cable for the DATA and GND lines were connected from the controller to a branching point, from which each 500-LED matrix is connected via an additional 5 to 40 meters of cable carrying DATA and GND lines. Everything operates properly, with minimal voltage drop. Stable operation is also observed in serial connection setups.

Summary

Basic Rules for Reliable Connection of Addressable LED Strips:
● Use high-quality power supplies with sufficient power margin.
● Always connect the negative (-) lines of all involved power supplies (both for the controller and the LED strip).
● Install the power supply as close as possible to the beginning of the LED strip.
● If two lighting zones are used (in parallel or series), it is recommended to use a separate power supply for each segment.
● Use conductors with an appropriate cross-section for powering the strip, calculated based on the required power.
● Connect the DATA and GND lines using shielded cable, routed at a distance from power and supply lines.