Who needs which number
Three people will ask you for a figure before an LED wall can be installed, and each of them wants a different one. Getting them mixed up is how a job ends up with a supply that trips on a white frame, or a bracket sized for an average that the wall exceeds every day.
| Who asks | What they need | Not this |
|---|---|---|
| Electrician | Maximum power draw, and how it splits across circuits | Average power |
| Structural engineer | Total weight and how it lands on the fixing points | Kilograms per square metre alone |
| HVAC consultant | Heat load in BTU/h or kW at the duty cycle it will run | Peak heat, which will oversize the plant |
Average power and maximum
Data sheets print two power figures per cabinet or per square metre, and they are far apart:
- Maximum power is every pixel at full white at full brightness. It is a real state — a white slide, a snow scene, a broadcast card — not a theoretical worst case.
- Average power is typical mixed content, conventionally about a third of maximum. It is what the wall costs to run.
Size the electrical supply on maximum. Estimate running cost and heat on average. Quoting the average to an electrician is the single most common way to get a wall commissioned and then tripped by the first all-white test pattern.
Both scale linearly with cabinet count, which makes them easy — total = per-cabinet figure × number of cabinets. The per-square-metre version is derived from that, and is the one to use when comparing two products with different cabinet sizes.
Circuits, phases and inrush
A wall is not one load. It is a set of cabinets chained into power runs, and the maker specifies how many cabinets may share a run — commonly four to eight indoors, fewer outdoors where each cabinet draws more.
Three things to settle before the offer goes out:
- How many circuits. Maximum wall power ÷ the usable capacity of one circuit, derated. Then round up, because the runs also have to divide sensibly across the wall.
- Single or three phase. Anything past about 7 kW is usually three phase, and the cabinets should be distributed so the phases stay balanced when the content is not.
- Inrush. Switch-mode supplies draw a large, brief surge at power-on. Enough cabinets on one breaker will trip it every morning, which is why staged or sequenced power-up exists.
None of this is your responsibility to design as a distributor, but all of it is your responsibility to hand over. An offer that states the maximum draw, the number of runs and the phase requirement is an offer the electrician can price from.
Weight, total and per m²
Total weight is the cabinet weight times the cabinet count. Kilograms per square metre is the comparison figure, and it varies more than people expect:
| Class | Typical kg/m² | Why |
|---|---|---|
| Indoor fine pitch | 18 – 22 | Die-cast aluminium cabinets, no weatherproofing, shallow depth |
| Indoor SMD, older formats | 25 – 40 | Steel frames and deeper cabinets on 640 × 480 mm stock |
| Rental | 25 – 30 | Extra structure for rigging, curving and repeated handling |
| Outdoor | 27 – 40 | Sealed enclosures, thicker sections, wind loading |
Add the structure to the wall figure before anybody quotes a bracket. The mounting frame, trim and service access can add a third again, and the fixings have to reach something structural — which in a refurbishment is very often not where the drawing says it is.
What the structure actually carries
Kilograms per square metre is a comparison figure, not a load case. The wall does not press evenly on the building; it hangs from a frame, and the frame hands the whole load to a small number of fixing points.
Give the structural engineer four things:
- Total wall weight, and the weight of the mounting structure separately.
- The fixing pattern — where the points are, and how many.
- The depth, because the load is offset from the wall and that produces a moment.
- Whether anything will be rigged from it, and whether there is wind loading.
Heat, and the HVAC conversation
Essentially all the electrical power an LED wall draws leaves it as heat. That makes heat load easy to calculate and easy to forget: 1 watt = 3.412 BTU per hour.
The question is which power figure to convert. Peak heat is the right input for a plant that must never be caught out; average heat at the real duty cycle is the right input for a plant that would otherwise be oversized by a factor of three. Give both, and say which is which.
This is not a small effect. A 30 m² indoor wall at 400 W/m² average is 12 kW — about 41 000 BTU per hour, about the same heat as a hundred people standing in the room, all day.
A worked example
A roadside outdoor screen: ten by five 960 mm cabinets at 6.67 mm, running eighteen hours a day, all year. Every figure here is computed by the same engine the configurator uses.
| Figure | Value | Who it is for |
|---|---|---|
| Wall size | 9.60 × 4.80 m · 46.08 m² | Everyone |
| Cabinets | 50 | Logistics and installation |
| Total weight | 1 350 kg · 29.3 kg/m² | Structural engineer |
| Maximum power | 40.0 kW · 868 W/m² | Electrician — size the supply on this |
| Average power | 14.0 kW · 304 W/m² | Running cost and heat |
| Energy | 91 980 kWh per year at 18 h × 365 d | The customer’s finance director |
| Heat, peak | 136 486 BTU/h | HVAC, worst case |
| Heat, average | 47 770 BTU/h | HVAC, sizing case |
| Receiving cards | 50 | Control system quotation |
The gap between peak and average is the whole point of the table. Sizing the supply on 14.0 kW would be a fault. Sizing the cooling on 40.0 kW would be an expensive one.
What goes on the technical sheet
A technical sheet that accompanies a quotation should let three other trades start work without ringing you. That means, at minimum:
- Wall dimensions in millimetres, area in square metres, and the true aspect ratio.
- Cabinet grid and cabinet count, with the format named.
- Resolution, and whether it maps 1:1 to a standard input.
- Weight total and per square metre, with the mounting structure called out separately.
- Power average and maximum, per wall and per square metre, plus the phase requirement.
- Heat load at both average and peak.
- Receiving card count, processor model, and the redundancy scheme if there is one.
- Minimum and recommended viewing distance.
- Depth, including the service gap behind.
The free configurator computes every figure on that list except the processor and the mounting structure, and easyLED PRO prints them as a sheet with your logo alongside the offer.