How to calculate LED wall power consumption
Max vs average watts, amps per circuit, the 80% breaker rule and thermal load — the complete method for powering an LED wall safely.
By wikiLED team · Updated 19 August 2026
The two numbers on every datasheet
Every LED cabinet datasheet quotes two power figures. Maximum power is the draw at full white, full brightness — the worst case the electrical installation must survive. Average (or 'typical') power is a content-mix estimate, usually 30–40% of maximum, and it exists for one purpose: predicting the energy bill.
The most common and most dangerous mistake in LED power planning is sizing circuits on the average figure. Real content hits white flashes; a wall sized on averages trips breakers exactly when everyone is watching. Electrical sizing always uses maximum power; average power is for the operating-cost spreadsheet.
Watch the units. Some brands quote watts per cabinet, others watts per square metre, and a few put both in one cell. Per-cabinet numbers are what you multiply by; convert W/m² by multiplying with the cabinet's face area first.
From cabinets to watts
The wall's totals are plain multiplication — the subtlety was in choosing the right per-cabinet figure.
P_max = cabinets × max W per cabinet · P_avg = cabinets × avg W per cabinet
From watts to amps and circuits
Current is power divided by voltage: a 9,000 W wall draws about 39 A at 230 V or 75 A at 120 V. No single circuit carries that — the wall is fed as several power daisy-chains, each behind its own breaker.
The 80% rule sizes those chains: a continuously loaded circuit should not exceed 80% of its breaker rating (NEC 210.19; European practice matches). A 230 V / 16 A circuit therefore feeds at most 0.8 × 230 × 16 ≈ 2,944 W of cabinets — six 450 W cabinets, not eight.
Divide the wall's cabinets into chains under that limit and route each chain like the data serpentine. wikiLED's power wiring view does the split automatically from your voltage and breaker rating, and flags any chain that exceeds the safe load.
usable W per circuit = 0.8 × voltage × breaker A · cabinets per circuit = floor(usable ÷ max W per cabinet)
The heat has to go somewhere
Essentially every electrical watt becomes heat in the room — about 3.412 BTU/h per watt. A 9,000 W wall adds ~30,700 BTU/h, the output of a serious space heater, and it lands directly in front of the audience.
Hand the BTU/h figure to whoever owns the HVAC design early. For enclosed control rooms and small venues, cooling capacity is discovered too late more often than power capacity.
Worked example
A 5 × 4 wall (20 cabinets) of 450 W-max / 150 W-avg cabinets on 230 V with 16 A breakers: P_max = 9,000 W, P_avg = 3,000 W, total draw 39.1 A. Usable per circuit = 2,944 W → 6 cabinets per chain → 4 chains (balanced 5/5/5/5 by wikiLED). Thermal load ≈ 30,700 BTU/h.
Run these numbers on your own wall — free, no account.
Frequently asked
- Do I add the controller and processing to the power budget?
- Yes, but it is small: controllers and media servers typically add a few hundred watts against a wall's thousands. Add them to the same distro, not the cabinet chains.
- Does lowering brightness reduce power proportionally?
- Roughly, yes — a wall calibrated to 50% brightness draws close to half the LED power. Many indoor walls run at 30–60% of rated brightness, which is why average figures assume a content mix rather than full output.
- Single-phase or three-phase?
- Beyond a handful of circuits, walls are fed three-phase and the chains are balanced across phases. The per-chain math is identical; balance is what the distro design adds.