What size supply does a commercial kitchen need?

Most commercial kitchens need 100A-200A three-phase supplies. A small cafe might manage with 60-100A three-phase, while busy restaurants need 150-200A+. Calculate by adding all equipment ratings and applying 80% diversity for cooking equipment that cycles.

Do I need three-phase for a commercial kitchen?

Almost always yes. While a very small cafe might use single-phase, most commercial kitchens need three-phase for: large ovens/ranges (often 3-phase only), balanced loading, and capacity. DNO can upgrade supplies - allow 8-12 weeks lead time.

What cable size for a commercial oven?

Commercial ovens vary widely: small convection ovens might be 13A single-phase, while combi ovens are often 32A-63A three-phase. Check the data plate - a 20kW combi needs about 29A per phase on 3-phase, requiring 6mm² or 10mm² cable depending on length.

Does each piece of equipment need its own circuit?

Major cooking equipment should have dedicated circuits for isolation and protection. Smaller items (microwaves, food processors) can share appropriately-rated circuits. Refrigeration should be on separate circuits from cooking equipment to prevent trips affecting food storage.

What about extraction system electrics?

Commercial extraction needs dedicated electrical supply - typically 3-phase for larger canopies. Must integrate with gas interlock (if gas cooking present) for safety shutdown. Include make-up air systems in calculations. Allow for EC motor controls and speed regulation.

What is a gas interlock system?

Gas interlock ensures gas supply is cut if extraction fails - mandatory under Gas Safety Regulations for commercial kitchens. Electrical components include: current sensing on extraction, solenoid valve control, and indicator panel. Must be fail-safe design.

How do I calculate maximum demand for a kitchen?

List all equipment with ratings. Apply diversity: 100% for largest item, 80% for cooking equipment, 100% for refrigeration, 50-80% for small appliances. A kitchen with 80kW connected load might have 50-60kW maximum demand. Always confirm with equipment schedules.

What earthing is required in commercial kitchens?

Extensive supplementary bonding connects all metal equipment, worktops, sinks, and services. Main earth terminal, supplementary bonding bars, and individual equipment bonds create a safe equipotential zone. Essential in wet environments with electrical equipment.

Do commercial kitchens need RCD protection?

Yes, 30mA RCD protection for socket outlets. Commercial equipment circuits may use different arrangements - consult BS 7671 for specifics. Some high-integrity equipment (refrigeration) may need RCBOs to prevent nuisance tripping affecting multiple circuits.

What regulations apply to commercial kitchen electrics?

BS 7671 Wiring Regulations, plus: Electricity at Work Regulations, Gas Safety Regulations (for interlock), Food Hygiene Regulations (cleanable installation), Building Regulations Part P and Part B (fire). Environmental Health may inspect before opening.

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Commercial Kitchen Cable Sizing Calculator

Calculate the correct cable size for commercial kitchens, restaurants, and catering equipment

Commercial Kitchen Cable Quick Facts

Commercial kitchens typically need 100A-200A+ three-phase supply
Individual equipment often 16A-63A per circuit
Extraction systems need dedicated circuits (often 3-phase)
Multiple earth bonding points required for metal equipment
Emergency stop systems mandatory for gas interlock

Cable Size Calculator

BS 7671:2018+A2:2022 compliant

1. Load Current

2. Cable Length (meters)

3. Installation Method

Lighting circuit (3% voltage drop limit)

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Common Commercial Kitchen Installations

Small cafe (2-3 cooking appliances)

100A three-phase supply, multiple 32A circuits

Restaurant kitchen (full range)

150-200A three-phase, dedicated circuits per major appliance

Commercial oven/range

32A-63A three-phase circuit, 6mm²-16mm² depending on rating

Extraction canopy system

Dedicated 3-phase circuit, gas interlock integration

Walk-in cold room

16A-32A dedicated circuit, consider soft-start for compressor

Related Commercial Electrical Calculations

Commercial kitchens are part of larger fit-outs. See our shop and retail unit calculator for front-of-house electrics. For cold storage facilities, check server room cooling principles. Need three-phase for other equipment? Our commercial AC guide covers similar requirements.

Commercial Kitchen Cable Sizing

Commercial kitchen cable sizing calculates conductor sizes for high-power catering equipment. Unlike domestic, commercial kitchens use three-phase supplies with individual circuits for major appliances. Total connected load often exceeds 50kW, requiring careful maximum demand calculation with diversity factors specific to catering operations.

Commercial Kitchen Electrical Costs (2024)

Typical UK installation costs for electrical work only. Excludes equipment and other trades.

Installation Scenario	Materials	Labour	Total
Small cafe fit-out (electrical only)	£2000-4000	£3000-5000	£5000-9000
Restaurant kitchen (full install)	£5000-10000	£6000-12000	£11000-22000
Three-phase supply upgrade	£1500-3000	£1000-2000	£2500-5000
Extraction system electrical	£800-1500	£1000-1800	£1800-3300
Gas interlock system	£400-800	£500-900	£900-1700

Prices as of 2024. Costs vary significantly by kitchen size and equipment specification.

Three-Phase Distribution

Commercial kitchens use three-phase (400V) supplies to handle high loads and balance across phases. Large equipment connects to all three phases; smaller items to single phases. Proper phase balancing prevents overloading individual phases. Distribution boards are typically 3-phase with single and 3-phase MCBs/RCBOs.

Phase Balancing

Three-phase systems should have roughly equal load on each phase. Unbalanced loads cause neutral current, voltage imbalance, and inefficiency. When planning commercial kitchen circuits, distribute single-phase equipment across all three phases. Large three-phase equipment naturally balances itself.

Equipment Isolation Requirements

Commercial kitchen equipment needs local isolation for maintenance and emergencies. Rotary isolators or lockable switches near each major appliance. Emergency stop buttons at exits for rapid shutdown. Equipment must be isolatable without affecting refrigeration or critical services.

Frequently Asked Questions

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