Hall 16 × 12 m LED lighting

Given: hall 16 m × 12 m, E = 300 lm/m², 55 W LED at 90 lm/W, UF = 0.8, MF = 0.8, supply 400 V, 3-phase, 4-wire. Assumptions: mounting height 3 m above working plane, SHR ≤ 1.5, pf 0.9.

Number of luminaires

Lumen method: N = (E × A) / (φ × UF × MF), where φ is the output of one luminaire.

Area A        = 16 × 12 = 192 m²
φ per luminaire = 55 W × 90 lm/W = 4950 lm
Total lumens  = E × A / (UF × MF)
              = 300 × 192 / (0.8 × 0.8)
              = 90000 lm
N             = 90000 / 4950 = 18.18

Rounding up and fitting a regular grid: 5 × 4 = 20 luminaires (5 along the 16 m side, 4 along the 12 m side).

Arrangement and spacing

Spacing along length = 16/5 = 3.2 m
Spacing along width  = 12/4 = 3 m
End spacing (to wall) = half of these
Max spacing = SHR × Hm = 1.5 × 3 = 4.5 m
3.2 m and 3 m ≤ 4.5 m  → OK
Actual E = 20 × 4950 × 0.8 × 0.8 / 192
         = 330 lux (≥ 300 lux required)

Layout diagram

Plan 16 m × 12 m (letter = phase of lamp circuit)
+-----------+
| R R R R R |
| Y Y Y R R |
| Y Y Y Y B |
| B B B B B |
+-----------+
[DB]  [SB]  <- entrance: DB and switch board
       S S S S ... one switch per sub-circuit

Each light sub-circuit is controlled by one 6 A one-way switch; all switches are grouped on a switch board (SB) next to the entrance, and the DB is mounted beside it.

Sub-circuits

Rule (IS 732 / NEA practice): a light sub-circuit carries at most 10 points and 800 W. Here one luminaire is 55 W, so up to 10 luminaires per sub-circuit. Number of circuits is made a multiple of 3 for phase balance.

Distribution board design

Total connected load = 1100 W (lighting)
Most loaded phase    = 385 W
Iph = 385 / (230 × 0.9) = 1.86 A
Main MCB ≥ 1.25 × 1.86 = 2.32 A → 6 A TPN MCB

DB specification: 4-way-per-phase TPN DB (12 ways in all, spares included) with 6 A TPN MCB as incomer, 25 A 4-pole RCCB (100 mA) for earth-leakage protection, 6 A SP MCBs (B-curve) for light circuits. Incoming cable: 4-core 1.5 mm² Cu PVC (rating 21 A ≥ 6 A), plus earth continuity conductor.

3-phase, 400/230 V, 4-wire supply
        |
   [Energy meter]
        |
   [6 A TPN MCB]
        |
   [25 A 4P RCCB]
        |
==R====Y====B====N== busbars
  |    |    |    |    |
  L1   L2   L3  ...