Every SmartMāja panel starts as an empty enclosure and ends as a CE-certified, tested, documented control centre. This walkthrough covers the assembly process step by step — from DIN-rail layout through to handover documentation — as performed in our workshop.

Step 1: Enclosure selection and DIN-rail layout

We use Hager UK (flush-mount) and VS (surface-mount) enclosures, or Spelsberg TK-L IP65 enclosures for outdoor or damp locations. Enclosure selection is driven by: IP rating (IP30 for dry indoor panels, IP65 for plant rooms and outdoor cabinets), number of DIN-rail modules required (each row = 18 modules per 600mm width), and spare capacity requirement (minimum 25% spare module space for future expansion, minimum 20% spare cable duct space). DIN-rail layout is designed in advance using CAD or Excel: row 1 = incoming supply, SPDs, main incomer MCB; row 2 = RCDs/RCBOs for distribution circuits; row 3 = KNX power supplies, DALI controllers, Modbus gateways; rows 4+ = KNX actuators, binary input modules, dimmer actuators.

Step 2: Mechanical assembly — DIN-rails, cable ducts and gland plates

DIN-rails are cut to length with a hacksaw and fitted into the enclosure using M6 bolts or snap-fit clips. Cable duct (PVC, 60mm × 40mm for main runs, 40mm × 25mm for secondary runs) is fitted between rows and vertically on each side. Cable duct fill: maximum 60% to allow cable routing and future additions. Gland plates are measured and drilled for cable entry: circular knock-outs for cable glands (M20 for 4-10mm cable, M25 for 10-20mm cable), rectangular cut-outs for multi-core trunking entries. All metal edges are deburred.

Step 3: Busbar and earth bar installation

The main busbar (copper flat bar, 10mm × 3mm for panels up to 63A, 25mm × 5mm for panels up to 125A) is installed on Hager or Schneider insulators. Neutral bar (blue insulator) and PE bar (green/yellow insulator) are installed. PE bar is bonded to the enclosure PE lug with a 16mm² green/yellow cable. Test link installed between neutral bar and PE bar (for TN-S systems — allows verification of neutral-PE separation).

Step 4: Component installation on DIN-rail

Components are clipped onto the DIN-rail in the designed order. Spacing: MCBs need no gap between each other. RCDs require 1-module gap each side for adequate heat dissipation in some models (check datasheet). KNX power supplies need 1 free module gap on each side for ventilation. Large contactors and motor starters need increased spacing per manufacturer data. Apply adhesive labels to each module position (position number matching circuit schedule). All toggle-switch MCBs are set to OFF before wiring begins.

Step 5: Power circuit wiring

Cables enter through glands or trunking into the cable duct. Mains wiring: 6491B single-core for internal panel wiring (brown = L, blue = N, green/yellow = PE). Cable cross-section per circuit: lighting 1.5mm², sockets 2.5mm², cooker 6mm², EV charger 10-16mm². For each circuit: route cable from gland plate through cable duct to correct MCB. Strip insulation to terminal depth (typically 12-14mm for MCBs). Insert into terminal and tighten to manufacturer torque (Hager: 2.5Nm for 6-16mm² terminals). Leave 50-75mm service loop in cable duct at each component — allows future re-termination if terminal is damaged.

Step 6: KNX wiring

KNX bus wiring (YCYM 2×2×0.8mm² — red pair for bus +/-) routes separately from mains cables in dedicated cable duct or at minimum 50mm separation within the panel. KNX devices have 2 bus terminals (+ and -) — polarity is marked. Bus connections are typically via KNX bus coupler block (one per DIN-rail row) that distributes the bus to multiple devices on that row. From the bus coupler, short bus connection cables (MDT BUS00.01 pre-terminated connector) route to each KNX device. The KNX power supply (MDT STC-0640.02 or similar) connects to one end of the bus, not to the KNX device bus terminals — the power supply has dedicated output terminals.

Step 7: Labelling and marking

Every wire is labelled at both ends using heat-shrink labels or ferrule labels. Label format: circuit number — function — terminal number (e.g., "C12-LIGHT-L"). MCBs are labelled with circuit number and load (e.g., "C12 — Bedroom Lighting 6A"). Terminal blocks are numbered. The enclosure door carries the circuit schedule (A4, laminated, mounted inside door) and the nameplate (IEC 61439 required data: manufacturer, type, ratings, year).

Step 8: Testing before closure

Before closing the cable ducts, perform point-to-point continuity checks on every circuit: from the MCB to the outgoing terminal, using a continuity tester. This catches wiring errors before sealing. For KNX wiring: verify bus polarity at each device — reverse polarity does not damage KNX devices but prevents communication.

Step 9: Routine verification tests

All 8 IEC 61439 routine verification tests are performed: visual inspection, insulation resistance (500V DC, > 1MΩ), earth continuity (< 0.1Ω), loop impedance measurement, RCD trip time and current, protective measure verification, mechanical operation, dielectric check. Results logged in test protocol with date and tester signature.

Step 10: ETS6 programming and functional test

KNX power supply is connected. Bus voltage verified at 29V DC. Each KNX device is programmed via ETS6 (USB programming cable or IP interface). After programming all devices: functional test of every controlled circuit using ETS6 Group Monitor. Test: every pushbutton input, every dimmer channel, every shutter movement, every sensor. Client-specific tests: scene recall, time-switch operation, presence detector hold time.

Step 11: Documentation package

Final documentation package: complete circuit schedule (as-built), wiring diagram (SLD), IEC 61439 test protocol (signed), nameplate data sheet, ETS6 project backup (USB stick), component data sheets (QR code linked to online library), warranty card. All in physical folder delivered with panel.