LED Wall Power Requirements: Amps, Circuits and Three-Phase Balance
An LED wall that looks right on paper can still trip breakers on show day. This guide walks through the power math a crew chief or electrician needs before ordering distribution or a generator: total load, amps, circuit counts, the 80% continuous-load rule and three-phase balance. It is a planning aid — final distribution must be designed and signed off by a qualified electrician under your local code.
1. Start from the cabinet's rated maximum
Use the manufacturer's maximum power per cabinet, not the typical or average figure. Average draw depends on content and brightness; breakers trip on peaks, and a full-white frame is the peak.
Worked example (illustrative values): a 10 × 6 wall of cabinets rated 200 W maximum is 60 × 200 = 12,000 W. Add processors, switchers and other auxiliary loads on the same feed before going further.
2. Watts to amps
three-phase, per line: A = W ÷ (√3 × V line-to-line × PF)
PF is the power factor from the datasheet; if it is not stated, treat it as unknown rather than assuming 1.0. With PF 0.95, the 12,000 W example draws about 105 A on a single 120 V leg — impractical — or about 35 A per line on 208 V three-phase (12,000 ÷ (1.732 × 208 × 0.95)). That difference is why most walls of any size are fed three-phase.
3. The NEC 80% continuous-load rule
A load running three hours or more is continuous under the NEC, and a branch circuit serving it is sized at 125% of the load — the same thing as loading the breaker to no more than 80% of its rating. An LED wall on a show day is a continuous load.
20 A breaker → 16 A · 30 A breaker → 24 A
Equivalently, design load = connected load ÷ 0.8 — a 20% margin on top of what the wall actually draws.
4. How many circuits?
circuits = total load ÷ watts per circuit (always round up)
For the example at PF 0.95: a 20 A / 120 V circuit carries about 1,824 W, so 12,000 W needs 7 circuits. A 20 A / 208 V circuit carries about 3,162 W, so 4 circuits. Also respect the cabinet's own power-link limit — how many cabinets may be daisy-chained on one feed — which can force more circuits than the amps alone suggest.
5. Balancing three phases
On a three-phase service, assign circuits to L1, L2 and L3 so the line currents come out as close to equal as possible. An unbalanced feed overloads one leg while the others idle, pushes current onto the neutral and can drop a generator's usable capacity. Rules of thumb:
- Plan circuits in multiples of three where the wall allows it.
- Rotate phases row by row or zone by zone rather than giving one leg a whole side.
- Put processors and other aux loads on the lightest leg, and check the result.
- Never size the generator from the average draw — size it from the design load.
6. Doing it in LED Architect Pro
The power engine runs these steps live from the cabinet catalog and your service settings: connected and design loads with the 20% margin, per-phase line currents, 20 A / 30 A circuit counts and a power map that paints circuits, AC-entry points and phase badges onto the wall. Overloads and missing power inputs are flagged as findings — unknown values stay blank instead of being guessed.