Electrical provisioning is the item most often discovered too late on an LED project. The screen is fine, the content is fine, and then the venue has one 16 A circuit where the wall needs four. The calculation is simple — it is the assumptions that catch people.
The two numbers on every datasheet
LED cabinets are specified with max power and average power per square metre.
- Max power is what the cabinet draws with every LED at full white. This is the number you size cables and breakers from.
- Average power is what it draws with normal video content, typically 30 to 40 percent of max. This is the number that decides your electricity bill.
For a typical outdoor rental cabinet, expect roughly 500–650 W/m² max and 170–220 W/m² average. Indoor cabinets run lower.
The formula
max load (kW) = screen area (m²) × max power (W/m²) ÷ 1,000
Worked example: a 20 m² outdoor wall at 600 W/m² max.
- 20 × 600 = 12,000 W = 12 kW maximum
- Average draw at 35 percent: about 4.2 kW
The 12 kW is what the supply has to survive, the 4.2 kW is what you will actually pay for.
Diversity factor: why you do not multiply by 1.0
If you size the supply at exactly 12 kW, every breaker will sit at its limit and nuisance trips become likely. Standard practice is to add headroom — commonly 20 to 25 percent — for inrush current at switch-on, for controller and cooling loads, and for the fact that a full-white test pattern is used during commissioning.
At 12 kW, that means provisioning about 15 kW. On a three-phase supply, 15 kW is roughly 22 A per phase at 400 V, so a 32 A three-phase feed gives comfortable margin.
Single phase or three phase
Small walls, up to roughly 5–6 kW, can run on a single-phase supply. Above that, three-phase is normal and usually required by the venue. Two things to plan:
- Balance the phases. Distribute cabinets so each phase carries roughly a third of the load. An unbalanced wall trips breakers that look oversized on paper.
- Count the circuits. A wall is usually split across several circuits, each with its own breaker. Ask the venue how many independent circuits are available before you agree a size.
Generators
For outdoor events, the generator has to cover the screen’s max load plus the rest of the production, and it has to handle inrush. A screen that draws 4 kW average can trip a 5 kW generator at switch-on.
Two practical rules: keep the screen on its own circuit within the distribution, and never run a generator at more than about 80 percent of its rated continuous output with the screen at full white.
Reducing consumption without losing quality
- Brightness schedule. Running at 20 percent overnight cuts daily energy by more than half. On a 6,000-nit outdoor wall this is the single biggest saving available.
- Ambient light sensor. The screen follows the sun instead of running flat out all day.
- Content discipline. Full-white slides and white backgrounds draw maximum current. Dark backgrounds on a large wall can cut average draw noticeably.
- Correct brightness for the position. Buying 6,000 nits for a shaded wall guarantees you never need the top of the range. See how many nits you actually need.
Common mistakes
- Sizing from average power. The breaker sees max power at switch-on and during white test patterns, not the average.
- Forgetting the controller and cooling. They add load, usually a few hundred watts, and they need their own circuit.
- Ignoring cable length. Long runs from the distribution to the wall cause voltage drop; cable size is set by current and distance, not by the cabinet connector.
- Assuming the venue has what you need. Ask for the circuit count and breaker rating in writing before quoting.
- Not checking the screen area after the design changes. The size usually grows during planning, and the electrical plan does not always follow.
Frequently asked questions
How much power does a 10 m² LED wall use?
At 600 W/m² max, about 6 kW peak and roughly 2 kW average with normal content.
Does pixel pitch change power consumption?
Yes, indirectly. A finer pitch packs more LEDs and drivers into the same area, so it usually draws more per square metre at the same brightness.
Does a brighter screen always use more power?
At the same content and size, yes — brightness is bought with current. But a scheduled 6,000-nit screen can use less over 24 hours than an unscheduled 3,000-nit one running flat out.
Can I run an LED wall from a normal mains socket?
Only for very small walls. Above a few kilowatts you need a dedicated circuit, and above roughly 6 kW a three-phase supply.
Send the size, we will send the electrical requirement
Give us the width, height, indoor or outdoor and the pitch, and we will return the max load, the average load and the recommended supply. Cabinet-level figures for a typical outdoor build are on the EA1000H9 rental LED wall page, or ask us directly through the contact page.