Smart home — more than gadgets
When a client says "smart home", the electrical engineer should think not about voice assistants but about a fundamentally different power supply topology. A smart home is a distributed system with dozens of devices needing power, protection, and communication.
Let's break down the key aspects of smart home electrical design.
1. Expanded panel
A typical apartment panel: 12-24 modules. For a smart home, plan minimum 36-54 modules. What's added:
- MCBs for automation controllers (separate group)
- MCBs for 24V power supplies (LED strips, sensors, actuators)
- Socket group inside the panel (router, switch, automation server)
- RCBOs for "wet" zones with leak sensors
- Contactors for power circuits (relay-controlled)
- Space for DIN-rail controllers (KNX, Loxone, Wiren Board)
Rule: smart home panel — no less than 48 modules. 60 is better.
2. Separate automation power
Smart home controllers (KNX bus, Loxone, Wiren Board, Home Assistant on Raspberry Pi) need stable 24V DC or 5V DC. Never put them on the same group as power loads.
Solution:
- Dedicated C6 MCB → DIN-rail SMPS 230V→24V DC
- UPS for critical automation: clean shutdown on power loss
- PoE switch (sensor and camera power over twisted pair) — C6 MCB
3. ELV cables and protection
A smart home needs a separate ELV panel (or section):
- Twisted pair UTP/FTP Cat 6A: IP cameras, Wi-Fi APs, PoE sensors, KNX/IP gateways
- KNX cable (2×2×0.8 mm): green bus cable, separate from power lines
- Coax RG-6: TV points (increasingly moving to IPTV)
- Speaker cables: for built-in speakers
Installation rules (IEC 60364):
- Minimum 300 mm separation between power and ELV cables
- Cross at right angles
- ELV cables in separate conduits
- Mandatory labeling of all cables
4. Redundancy and emergency modes
A smart home must not "die" on internet or power loss:
- Basic lighting (stairs, corridors) — manual bypass (relay modules with manual control)
- Fridge, freezer, server room — dedicated MCBs with ATS
- Automation UPS: minimum 30 minutes for clean shutdown
- Generator or PowerWall: for houses (optional, but plan ATS input)
5. Surge and noise protection
Controllers and sensors are noise-sensitive:
- SPD Class II at input — lightning and switching surge protection
- Line filters on controller power supplies
- Separation: power cables left, ELV right inside the panel
6. Protocol integration: KNX, Zigbee, Wi-Fi, Matter
A modern smart home is a protocol zoo. The engineer must plan physical infrastructure:
- KNX: dedicated twisted pair (green cable), bus topology, up to 700 m
- Zigbee: no cable needed, but plan router placement every 10-15 m. Specify outlets with built-in Zigbee routers
- Wi-Fi: ceiling-mounted APs with PoE. One AP per 40-60 m²
- Matter/Thread: border routers (Apple HomePod, Google Nest Hub) — plan outlets at 1.2 m height
7. Documentation
Critical for smart homes:
- IP/MAC address map of all devices
- Group table: which MCB feeds which consumer
- ELV cable schedule: type, length, from-to
- Panel photos before/after wiring with readable labels
How GorkyCAD helps
- Expanded panel with automation section ("Smart Home" template)
- Automatic thermal calculation for large panels
- ELV section with separate groups and conduits
- Documentation export with detailed labeling