Three-Phase Power Explained for Business Owners

Your facility needs industrial power. Supplier says "you need three-phase." What does that mean? Why not regular power? Why does it cost differently?

Here's what every business owner should know about three-phase power.

Single-Phase (Household Power)

Your home runs on single-phase: one power wire delivering power in waves. Think of it as a pulsing river—up, down, up, down.

Capacity: 6-15 kW typical home

Voltage: 230V (Kenya standard)

Use case: Lights, fridges, small AC units, computers

Three-Phase Power (Industrial)

Three separate power wires, each delivering power at slightly different times. Result: smoother, stronger power delivery.

Capacity: 50 kW - 500 kW+ (scalable)

Voltage: 380V/400V (Kenya industrial standard)

Use case: Industrial motors, heavy machinery, large AC systems, production equipment

Why Three-Phase Is Better for Industry

1. More Power Capacity — Three-phase delivers 1.73× more power than single-phase at the same voltage. 400V three-phase = 100 kW. Single-phase = 57 kW max.

2. Smoother Power Delivery — Three waves instead of one = fewer voltage dips = machines run smoother = less vibration + wear.

3. Better for Motors — Large industrial motors MUST be three-phase. Single-phase motors above 3-5 kW become inefficient and overheat.

4. Lower Cost Per Watt — KES 1.2-1.5 per watt three-phase vs KES 2-3 per watt single-phase.

Cost: Single vs Three-Phase

When to Use Each

Single-Phase: Offices, retail stores, small workshops, homes

Three-Phase: Manufacturing, large data centers, hospitals, commercial kitchens, industrial facilities

Converting Single to Three-Phase

If your facility has single-phase but needs three-phase:

Option 1: Request from Kenya Power — If supply line is available. Cost: KES 200K-2M depending on distance. Timeline: 3-8 weeks.

Option 2: VFD (Variable Frequency Drive) — Converts single-phase to three-phase for motors. Cost: KES 200-500K. Good for one or two motors.

Option 3: Three-Phase Converter — Rotary converter generates three-phase from single-phase. Cost: KES 150K-400K. Maintains supply for whole facility.

Three-Phase and Backup Power

Generator Requirement: If you need three-phase power, your backup generator must also provide three-phase.

Example: Industrial facility with 50 kW three-phase load needs 60-70 kVA three-phase generator (not single-phase).

Cost Implication: Three-phase generators cost same as single-phase (no premium). But you need larger capacity for same load.