Before you wire an LED screen you need four numbers: how many LAN (Ethernet) ports the controller needs, how many power lines run to the screen, what cable size (sq mm) each line needs and which MCB protects it. This guide shows how to calculate all of them step by step, with the formulas, a cable size table and a full worked example for a 16 × 9 ft (5 × 3 cabinet) indoor LED video wall on a single-phase supply.
Want the answer straight away? Our free LAN and power cable calculator does every step below for your own screen and draws the LAN map and power map. The screen raw material calculator includes the same section for the cabinet layout you choose.
Quick answer: the formulas
| What | How to calculate it |
|---|---|
| Pixels per cabinet | modules across × modules down × pixels per module |
| LAN ports | whole columns of cabinets per port, up to 6,55,360 px per Gigabit port; a column that is too big is split |
| LAN cables | long runs = number of ports; short jumpers = cabinets − ports |
| Current per cabinet | modules × module max power (W) ÷ mains voltage ÷ power supply efficiency |
| Power lines | whole rows of cabinets per line, up to about 22 A per line on single phase |
| Line MCB | next standard MCB above line current + 10% (C-curve, at least 10 A) |
| Cable size | smallest copper cable rated for the MCB; at least 2.5 sq mm, and 4 sq mm for screens over 100 sq ft |
| Main supply | total current + 25% for the main MCB and its cable; above about 63 A, split the supply |
What you need before you start
- The module: size (for example 320 × 160 mm), pixels (for example 128 × 64 px at P2.5) and maximum power per module in watts, from the module datasheet. Every module on our LED modules pages lists these.
- The cabinet layout: cabinet size and how many cabinets across and down.
- The controller: how many pixels one LAN output carries. For a Colorlight Gigabit output this is 6,55,360 px at full load.
- The mains supply: usually 230 V single phase in India.
Step 1: Pixels per cabinet
Count the modules in one cabinet and multiply by the pixels of one module.
Example: a 960 × 960 mm cabinet holds 3 × 6 = 18 modules of 320 × 160 mm. At P2.5 each module is 128 × 64 px, so the cabinet is 384 × 384 = 1,47,456 px.
Step 2: How many LAN ports does an LED screen need?
Each LAN (Ethernet) output of the sending card or controller can drive a limited number of pixels. A Colorlight Gigabit output carries up to 6,55,360 px; many installers keep a margin and plan 5 to 6 lakh px per port.
Run each port through whole columns of cabinets (or whole rows), and start every port at the same edge of the screen, usually the bottom. Never start a new port at the cabinet where the previous port ended. This keeps the cabling neat, makes the mapping in the software simple and makes faults easy to trace. If one column alone has more pixels than one port can carry, split that column into parts with a port each.
Example: one column of 3 cabinets is 3 × 1,47,456 = 4,42,368 px (68% of a port). Two columns would be 8,84,736 px, too much for one port, so each of the 5 columns gets its own port: 5 LAN ports.
Step 3: How many LAN cables?
- Long LAN cables (controller to the first cabinet of each port) = number of ports. Use CAT6 and keep each run under 100 m; for longer runs use fibre.
- Short LAN jumpers (cabinet to cabinet) = cabinets − ports. Usually 1 to 1.5 m each.
Example: 5 long CAT6 cables and 15 − 5 = 10 jumpers. The controller needs at least 5 LAN outputs.
Step 4: LED screen power and current per cabinet
Use the maximum power of the module from its datasheet, not the average, so the wiring is safe when the screen shows full white.
Cabinet power = modules per cabinet × module max power.
Cabinet current (A) = cabinet power ÷ mains voltage ÷ power supply efficiency (about 85%).
Example: 18 modules × 24 W = 432 W. 432 ÷ 230 V ÷ 0.85 = 2.21 A per cabinet. The whole screen of 15 cabinets is 6.5 kW at peak. In normal use with video, an LED screen draws about one third of its peak, here about 2.2 kW.
Step 5: How many power lines?
Feed the screen with several power lines from a distribution board, each looping (daisy-chaining) from cabinet to cabinet. Plan up to about 22 A per line on a single-phase supply. Like LAN, let each line take whole rows of cabinets starting from the same edge, and put every cabinet on exactly one power line, never fed from two.
Example: one row of 5 cabinets draws 5 × 2.21 = 11.05 A. Two rows would be 22.1 A, just over the limit, so each row is its own line: 3 power lines and 15 − 3 = 12 power jumpers.
Step 6: Power cable size (sq mm) and MCB for an LED screen
Choose the MCB first, then a cable that can safely carry the MCB's rating. Use C-curve MCBs: many power supplies switching on together draw a short surge that can trip a B-curve MCB.
| Copper cable | Safe current (in conduit or bunched) | Typical MCB | About this much LED screen at 230 V |
|---|---|---|---|
| 2.5 sq mm | about 20 A | 16 to 20 A | up to about 3.5 to 4 kW |
| 4 sq mm | about 27 A | 25 A | up to about 5 kW |
| 6 sq mm | about 35 A | 32 A | up to about 6.5 kW |
| 10 sq mm | about 50 A | 40 to 50 A | main supply of a mid-size screen |
| 16 sq mm | about 66 A | 63 A | main supply of a large single-phase screen |
- Line MCB: next standard size above the line current + 10%, never below 10 A.
- Line cable: at least 2.5 sq mm; use 4 sq mm on screens over about 100 sq ft.
- Long runs: the table holds for runs up to about 20 m. For longer runs go one size up to keep the voltage drop low (a 4 sq mm copper cable loses about 11 mV per amp per metre).
- Earth every cabinet frame.
Example: each line carries 11.05 A, so a 16 A C-curve MCB. The screen is about 149 sq ft, so the lines use 4 sq mm cable.
Step 7: Main supply and single-phase limit
Add up the current of all lines and add 25% for the main MCB. Size the main cable for that MCB.
Example: 15 × 2.21 = 33.1 A. 33.1 + 25% = 41 A, so a 50 A main MCB with 10 sq mm copper cable.
If a screen needs more than about 63 A in total, one single-phase supply is not enough. Split it into two or more separate supplies, or use a 3-phase supply designed by an electrician.
Worked example: summary
| Screen | Result |
|---|---|
| Screen | 5 × 3 cabinets of 960 × 960 mm, P2.5 indoor, 4800 × 2880 mm, 1920 × 1152 px |
| LAN | 5 ports, 5 long CAT6 cables, 10 jumpers |
| Power | 6.5 kW peak (about 2.2 kW typical), 33.1 A total |
| Power lines | 3 lines of 5 cabinets, 11.05 A each, 16 A C-curve MCB, 4 sq mm cable, 12 jumpers |
| Main supply | 50 A main MCB, 10 sq mm copper cable |
Common mistakes
- Using the average power instead of the maximum power from the datasheet, which leaves the wiring too thin.
- Loading a LAN port to 100% and starting the next port where the last one ended, which makes the screen hard to map and to service.
- Feeding one cabinet from two power lines, or putting the whole screen on one long chain.
- Using a B-curve MCB that trips when all the power supplies switch on.
- Forgetting the voltage drop on long cable runs, and forgetting to earth every cabinet.
For reference only. This guide and our calculators give a helpful starting point and can contain errors. Always have the final design and wiring checked by a qualified electrician or professional installer and follow local electrical rules. MG TechLink cannot accept responsibility for any loss, damage or injury arising from their use. Pixel loads are for Colorlight Gigabit outputs; check your own controller's datasheet.
Frequently asked questions
How many pixels can one LAN port of an LED screen controller carry?
A Colorlight Gigabit LAN output carries up to 655,360 pixels (6,55,360 px). Many installers plan 5 to 6 lakh pixels per port to keep a margin. Run each port through whole columns or rows of cabinets and start every port at the same edge of the screen.
How do I calculate the number of LAN ports for an LED screen?
Work out the pixels of one cabinet (modules across x modules down x pixels per module), then the pixels of one column of cabinets. Put as many whole columns on one port as fit within the port's pixel load; split a column that is too big. The number of groups is the number of LAN ports. Long LAN cables = ports, jumpers = cabinets minus ports.
How do I calculate LED screen power consumption?
Multiply the number of modules by the maximum power of one module from its datasheet. For example 270 modules x 24 W = 6.5 kW peak. In normal use with video an LED screen draws about one third of its peak power.
Which cable size should I use for LED screen power?
Use copper cable sized for the MCB of each power line: at least 2.5 sq mm, and 4 sq mm for screens over about 100 sq ft. A 4 sq mm copper cable safely carries about 25 to 27 A on single phase. For runs longer than about 20 m go one size up.
Which MCB should I use for an LED screen power line?
Use a C-curve MCB one standard size above the line current plus 10%, at least 10 A. For example a line drawing 11 A gets a 16 A C-curve MCB. The main MCB is sized from the total current plus 25%.
How many LED cabinets can go on one power cable?
Add up the current of the cabinets on the line and keep it under about 22 A on single phase. A cabinet current is its power divided by the mains voltage and the power supply efficiency, for example 432 W / 230 V / 0.85 = 2.2 A, so up to about 9 or 10 such cabinets per line. Every cabinet should be on exactly one power line.
Can a large LED screen run on a single-phase supply?
Up to about 63 A in total, about 12 to 14 kW peak, yes. Above that, split the screen over two or more separate supplies or use a 3-phase supply designed by an electrician.
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