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Practical 2025-07-30 · 7 min

Top 5 mistakes in apartment panel layout design

Breaking down five critical mistakes in apartment panel design: from insufficient modules to wrong RCD selection. With fixes.

Author: GorkyCAD Team

Why panel layout matters

The panel is the heart of an apartment's electrical installation. Layout mistakes mean: inconvenient maintenance, no expansion capability, overheating, and in the worst case — fire. Yet a correctly designed panel costs only 10-15% more than a flawed "budget" version.

Let's examine the five most common mistakes we see in novice electricians' projects.

Mistake 1: Panel with zero module reserve

Problem: designer counts modules exactly for the current scheme. 12-module panel for a studio: main C32 (2), RCD (2), 4 MCBs (4), neutral + earth bars (2), terminals (2) = 12 — "everything fits".

A year later, client installs AC — needs another C16. No space. Panel replacement: chasing, new panel, moving all devices.

Solution: always allow 30-40% reserve modules. Studio minimum: 18-20 modules; 2-3 bed apartment: 24-36 modules. Cost difference between 24-module and 12-module panel: ~$5-10 — savings that backfire.

Mistake 2: One RCD for all groups

Problem: a single 40A/30mA RCD for all socket circuits. It trips — all sockets go dead: fridge defrosts, computer loses unsaved work, aquarium light goes out.

Per IEC 60364: splitting across multiple RCDs is recommended for tripping selectivity. Optimal: separate RCD for "wet" zones (kitchen, bathroom), separate for living rooms.

Solution: minimum 2-3 RCDs per apartment panel. Grouping: RCD1 — kitchen (sockets + stove), RCD2 — bathroom + washer, RCD3 — living rooms. One trips — others keep working.

Mistake 3: Neutral bar in wrong place

Problem: neutral bar at panel bottom, RCD at top. N wires cross the entire panel, creating EMI and complicating maintenance. Worse: neutral wires from different RCDs mixed on a common bar — RCD will nuisance-trip because the current sum through it is non-zero.

Solution: separate neutral bar (or section) per RCD, placed adjacent to its RCD. Group line neutrals connect to their RCD's bar. Pre-RCD and post-RCD neutral bars physically separated.

Mistake 4: Panel in a niche without depth margin

Problem: panel in an 80 mm deep niche. IP41 enclosure, 76 mm deep. "Almost fits." But internal wiring adds volume. Cover won't close without force. Wires get pressed — insulation wears against enclosure edge within a year.

Solution: niche depth should exceed panel + wiring depth by 10-15 mm. Or use surface-mount panel (no niche needed).

Mistake 5: No voltage monitoring relay

Problem: neutral break in floor panel → phase imbalance → 380 V instead of 230 V enters apartment. All connected equipment burns out in seconds. Damage: $600-3,500+.

Per modern standards: overvoltage protection required in residential (SPD Class II or voltage relay).

Solution: voltage monitoring relay at input — disconnects load when voltage exceeds 170-270 V limits. Cost: from ~$20. Pays for itself on the first surge.

Additionally: SPD Class II for lightning and switching surge protection — mandatory for overhead supply lines.

How GorkyCAD prevents these

1. Warns at >85% panel module fill

  • 2. Recommends multiple RCDs by room function
  • 3. Auto-builds N-bar topology per RCD
  • 4. Checks niche depth vs panel depth
  • 5. Recommends voltage relay and SPD based on supply type