This case documents mall linear led strip lighting replacing a failing ceiling-slot line above the west wing of a Poznań shopping centre — Approx. 180 m of continuous 40 mm slot across two levels, plus an Approx. 32 m feature run at the atrium edge. The operator set one rule: no cherry-picker on the floor in opening hours. Part of our commercial LED strip lighting work.
What Actually Hides the Dots — and It Is Not the Ceiling Height
The usual argument for SMD over COB in mall linear led strip lighting is that nobody sees dots from that far. Check it: one arcminute of acuity is Approx. 0.29 mm per metre, so at Approx. 4.2 m the eye resolves Approx. 1.2 mm. SMD 2835 at 120 LEDs/m has an Approx. 8.3 mm pitch — roughly 7 arcminutes, comfortably resolvable. A bare strip in an open slot at this height reads as a dotted line, and stops resolving only past Approx. 28 m.
So what makes SMD correct here is the opal diffuser and the cavity behind it, not the distance. Blending needs air gap roughly proportional to pitch — around 6 mm minimum at 8.3 mm pitch — and a 40 mm profile gives far more. The specification that matters is diffuser grade and mounting depth, and those are the two numbers most often left off the drawing. COB earns its premium where a strip is viewed directly with no diffuser; behind opal at 40 mm depth it buys nothing visible.
The other reason for 24V is separate: both SKUs are 12V/24V parts, and at 24V a run carries half the current — fewer injection points, fewer ceiling penetrations, the logic behind our 24V LED strip lights range.
Products Used
| Role | SKU | Specs | Approx. Use |
|---|---|---|---|
| Main corridor line | ES-2835-120-8MM | SMD 2835, 120 LEDs/m, 8 mm, 12V/24V, CRI 80, 4000K, IP20 | Approx. 180 m |
| Atrium-edge feature slot | ES-2835-240-10MM | SMD 2835, 240 LEDs/m, 10 mm, 12V/24V, CRI 80, 4000K, IP20 | Approx. 32 m |
Both parts are IP20, correct for a sealed ceiling void and claiming nothing more. The 40 mm anodised profile and opal diffuser were specified by us but are not catalogue SKUs — they came through the contractor, and saying so matters because the diffuser grade does the visual work. Drivers are not ours either: our power supplies are 12V and IP20, and this wing needs 24V at Approx. 3.3 kW connected, so the contractor supplied twelve 24V constant-voltage units. We supplied strip, segment map, injection layout and bin specification. The 240 LEDs/m part goes only to the atrium edge, where shoppers on the upper level look along the slot at a shallow angle and take in a longer stretch at once; the corridor line does not need it. Where the same corridor logic applies to an office fit-out, that sits in commercial office LED lighting.
Designing for a 22:30–06:00 Window
- Segments of Approx. 15 m, each fed at both ends. Segment length follows service risk first: one failure darkens Approx. 15 m, not half a wing, and a night technician swaps one segment before opening. Both-end feed makes it viable — at 120 LEDs/m an Approx. 15 m single-end run at 24V would carry Approx. 8.8 A into the head end.
- Measured tail drop Approx. 2.1% on the longest segment, fed both ends.
- Twelve drivers grouped into three hatches beside existing HVAC access, not spread along the void. One tower position per hatch, no new access points cut, no cherry-picker.
- Every circuit is 24V SELV per IEC 61140.
- One 4000K bin across all Approx. 212 m, bin ID in the handover file, spot-checked at four points — spread Approx. ±80 K. Over a continuous slot a bin change reads as a join: a colorimetry matter settled on the PO.
- The whole west wing went in over one seven-hour night.
The 200 lx Figure, and Where It Actually Comes From
The brief called for Approx. 200 lx maintained at floor level, attributed to EN 12464-1. That attribution is wrong and worth correcting: the circulation-area requirement in that standard is 100 lx, and it addresses workplaces rather than retail concourse. The 200 lx came from the operator wanting the corridor to hold up against lit tenant shopfronts — a commercial decision, not a compliance one, and one that sets the load for all mall linear led strip lighting here.
A number carried as a standard requirement never gets questioned, and this one doubles connected load. Measured result was Approx. 205–230 lx — twice the standard’s circulation floor, by choice, documented as such.
Four Notes if You’re Relighting a Mall Corridor
- In mall linear led strip lighting, specify diffuser grade and cavity depth, not just LEDs/m. At 4.2 m the pitch is still resolvable; the diffuser hides it.
- Pick segment length from service risk before picking the strip, and check the current the feed arrangement implies.
- Group drivers at existing ceiling access. New hatches cost more than the drivers.
- Check which illuminance figures are standards and which are client preference. Only one of them is negotiable.
Senfey is a Chinese LED strip manufacturer established in 2013, based in Shenzhen, with in-house SMT and silicone extrusion lines producing Approx. 1.2 million metres per month across COB, SMD, neon flex and addressable. See our commercial building lighting range or request a corridor lighting quote.
