How to Assemble an Electrical Panel: A Step-by-Step Guide

Planning

Before assembling the panel, you need to draw up a single-line diagram, determine the number of circuits and select the protective devices. A typical panel layout for a two-room apartment is as follows:

• Main circuit breaker 2P, 32–40 A
• Fire-protection RCD (residual current device) 2P, 63 A, 100–300 mA
• RCD 2P, 40 A, 30 mA — for the socket group (1–2 units)
• Circuit breakers 16 A, curve C — socket circuits (4–8 units)
• Circuit breakers 10 A, curve B — lighting (2–4 units)
• Circuit breaker 25 A — electric range / oven
• RCBO (combined RCD + circuit breaker) 16 A, 10 mA — washing machine, bathroom
• Voltage relay (optional, but recommended)

Choosing the Enclosure

The enclosure is sized by the number of modules, with a 20–30% spare allowance. The standard module width is 18 mm (DIN rail). For an apartment an enclosure for 24–36 modules is usually enough; for a house, 48–72 modules.

• Surface-mounted — for drywall walls or where chasing is not possible
• Flush-mounted — for concrete and brick walls; looks neater

Installation Sequence

1. Mounting the enclosure at a height convenient for servicing, usually 1.4–1.7 m from the floor (a recommendation for ease of operation; the Russian Electrical Installation Code (PUE) sets no standardized mounting height for an apartment panel — PUE clause 7.1.28 specifies a protection rating of at least IP31)
2. Installing the DIN rails and the neutral/earth bus bars
3. Placing the circuit breakers in the order: main breaker → meter (if inside the panel) → fire-protection RCD → group RCDs → circuit breakers for the individual circuits
4. Connecting the busbar links (comb busbars) to distribute the phase from the RCDs to the circuit breakers
5. Connecting the outgoing circuits — cables from the loads to the lower terminals of the circuit breakers
6. Connecting the neutral conductors — to the neutral bus bars of the corresponding RCD groups
7. Connecting the PE (earth) — all yellow-green conductors to the common PE bus bar
8. Labeling — each circuit breaker is labeled (circuit number, purpose)

Important Rules

• Power is fed to the upper terminals of the circuit breakers, the outgoing circuits to the lower ones
• Solid-core cable is connected directly; stranded cable through insulated bootlace ferrules (NShVI)
• Each circuit breaker protects one circuit (do not combine circuits under a single breaker without calculation)
• Terminal tightening torque — 2–2.5 Nm (re-check 24 hours after installation)

Checks Before Switching On

1. Visual inspection: all connections tightened, no pinched wires
2. Insulation resistance test with a megohmmeter (no less than 0.5 MΩ)
3. Testing the RCD trip with the "Test" button
4. Stage-by-stage switch-on: main breaker → RCDs → circuits one at a time

All the components for assembling a panel are in the catalog. Need help with your selection? Get in touch with our engineers.