Electrical Safety

⚠️ WARNING: This document describes 230V AC mains voltage installation. Improper wiring poses risk of electric shock, fire, or equipment damage.

• If you are not experienced with mains-voltage wiring, hire a qualified electrician
• This guide is for informational purposes — local electrical codes may require certified installation
• This is a DIY project — not CE/UL certified for commercial use

Overview

The Pool Controller switches 230V AC mains voltage to pool and solar pumps. Improper wiring or installation poses risk of electric shock, fire, or equipment damage. Read this document carefully before connecting mains power.

If you are not experienced with mains-voltage wiring, hire a qualified electrician. This guide is for informational purposes — local electrical codes may require certified installation.

Hazard Assessment

General Safety Rules

1. Always disconnect power before working on the controller or pumps
2. Use a residual-current device (RCD/FI) on the controller circuit
3. Never work wet — ensure dry hands and dry environment
4. Use the correct fuse rating for your pump load
5. Keep mains and low-voltage wiring separated inside the enclosure
6. Secure all connections with strain relief
7. Label all cables clearly

Mains Wiring

Relay Output Wiring

The relay module switches the Live (phase) conductor only. The Neutral and Protective Earth connect directly to the pump.

AC Mains        Relay Module         Pump
┌────────┐     ┌──────────────┐     ┌─────┐
│ Live   ──────┤ COM    NO    ──────┤ L   │
│ (230V) │     │              │     │     │
│ Neutr. ───────────────────────────┤ N   │
│        │     │              │     │     │
│ Earth  ───────────────────────────┤ PE  │
└────────┘     └──────────────┘     └─────┘

Wire Sizing

Fuse Requirements

• Install a circuit breaker appropriate for your pump load
• The fuse should be on the Live conductor before the controller
• Use a DIN-rail or panel-mount fuse holder

Low-Voltage Wiring

ESP32 and Sensor Wiring

• ESP32 operates at 3.3V / 5V (USB power)
• DS18B20 sensors use 3.3V — max cable length: 10 m
• Keep sensor cables away from mains cables (min. 5 cm separation)
• Use shielded twisted-pair cable for long sensor runs

Power Supply

• Use a regulated 5V power supply (not a bare wall adapter)
• Minimum 1A for ESP32 + relay module
• For 12V pool systems, use a 12V→5V DC-DC converter

Enclosure Requirements

IP Rating

Enclosure Best Practices

• Use cable glands (PG9 or PG11) for all cable entries
• Install a drip loop on external cables before entering the enclosure
• Keep mains and low-voltage cables on opposite sides of the enclosure
• Use strain relief on all cables
• Ensure the enclosure can be locked or secured against tampering

Grounding

Protective Earth (PE)

• Connect the enclosure to protective earth if it is metal
• Connect pump motor protective earth
• Use green/yellow wire (min. 2.5 mm²) for ground connections
• Verify ground continuity with a multimeter before commissioning

Ground Loop Prevention

• Run all ground wires to a single ground point (star topology)
• Do NOT daisy-chain ground connections
• Use insulated crimp ring terminals on ground connections

Commissioning

Before Connecting Mains

1. Complete the Build from Zero breadboard test
2. Verify sensors return plausible readings
3. Test relay operation with a multimeter (no-load)
4. Confirm the enclosure is properly sealed

First Power-On with Mains

1. Do not leave the controller unattended for the first 30 minutes
2. Listen for unusual sounds (buzzing, arcing)
3. Check for warmth on relay terminals and power supply
4. Verify pump starts and stops correctly
5. Verify relay disengages when toggled OFF

Annual Inspection

• Check all screw terminals for tightness
• Inspect cables for damage or wear
• Test RCD/FI switch
• Clean enclosure ventilation openings
• Verify ground continuity

Emergency Procedures

If You Smell Burning

1. Immediately disconnect power at the circuit breaker
2. Do not touch the controller
3. Use a CO₂ or powder fire extinguisher (NOT water)
4. Have the installation inspected before re-use

If Someone Receives an Electric Shock

1. Do not touch the person if they are still in contact with power
2. Disconnect power at the circuit breaker
3. Call emergency services immediately
4. Begin first aid (CPR if trained) once power is disconnected

Related Documents

• Build from Zero — Complete build guide
• Hardware Guide — Hardware assembly details
• Safety Model — System safety architecture
• Production Checklist — Pre-deployment checks
• Security Checklist — Security hardening