What size electrical supply for a shop?

Small shops (under 50m²) typically need 60-80A single-phase. Medium shops often need 80-100A. Larger retail or those with high loads (food retail, salons) may need three-phase. Check landlord supply specifications - many retail units have capped supplies.

Do I need an EICR for a new shop?

Yes, commercial premises should have an Electrical Installation Condition Report before trading. Many landlords require this, and insurers expect it. For new fit-outs, you'll receive an Electrical Installation Certificate. EICRs should be repeated every 5 years for commercial.

What emergency lighting is required for shops?

All shops open to the public need emergency escape lighting. This illuminates exit routes when power fails. Maintained or non-maintained fittings depending on design. Monthly function tests and annual duration tests required. Part of fire risk assessment.

How do I calculate lighting load for retail?

Modern LED retail lighting: 15-25W/m² depending on type. A 100m² shop might need 1.5-2.5kW for general lighting, plus accent/display lighting. Use 20W/m² as reasonable estimate. Dedicated lighting circuits separate from socket circuits.

What about socket circuits for a shop?

Plan for: till points, display lighting plugs, back office equipment, staff areas. Ring or radial circuits depending on layout. Consider future flexibility - retail layouts change. Floor boxes useful for island displays. USB sockets increasingly expected.

Do I need a fire alarm in my shop?

Most retail premises need fire detection and alarm. Size and type depends on fire risk assessment. Simple shops may need Grade D (domestic-style) or Grade A (commercial) systems. Integration with emergency lighting and door releases may be required.

What if the landlord supply is limited?

Many retail units in older buildings have limited supplies (often 60-80A). Options: work within the limit, request supply upgrade (landlord/DNO), or install load management. Exceeding your allocated supply can affect other tenants and breach lease.

How do I handle shop security electrics?

Security typically includes: alarm system, CCTV, shutter controls, and access control. These need dedicated circuits and often UPS backup. Plan cable routes during fit-out. Coordinate with security installer for power requirements.

What regulations apply to shop electrics?

BS 7671 Wiring Regulations, Building Regulations Part P (if applicable) and Part B (fire), Regulatory Reform (Fire Safety) Order for emergency lighting, and potentially food hygiene regs for food retail. Landlord may have additional requirements.

Can I do shop electrical work myself?

Commercial electrical work should be done by qualified electricians. Part P applies to some commercial situations. Insurance, landlord requirements, and health & safety law all expect professional installation. Self-certification by registered electrician required.

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Shop & Retail Unit Cable Sizing Calculator

Calculate the correct cable size for retail shops, commercial units, and small business premises

Retail Unit Cable Quick Facts

Retail units typically need 60-100A single or three-phase
Lighting load often 10-20W/m² for retail display
EICR required before occupation (commercial premises)
Emergency lighting mandatory for public premises
Fire alarm integration often required

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 Retail Installations

Small retail unit (<50m²)

60-80A single-phase, lighting + socket circuits, emergency lighting

Medium retail shop (50-150m²)

80-100A single or three-phase, dedicated lighting circuits, back of house

Large retail store (150m²+)

Three-phase supply, multiple distribution boards, sub-metering

Food retail (café counter, deli)

Additional circuits for refrigeration, food prep - see commercial kitchen

Shop fit-out in shell unit

Full installation from landlord supply point, metering, DB, all circuits

Related Commercial Calculations

Food retail needs additional consideration - see our commercial kitchen calculator for cafés and food prep. Security is crucial for retail - check CCTV and security requirements. For office areas, see socket circuit calculations.

Retail Unit Cable Sizing

Retail unit cable sizing calculates conductor sizes for shop electrical installations. Retail has specific needs: high lighting levels for product display, multiple socket circuits for POS and displays, emergency lighting for public safety, and often security/CCTV integration. Supply size depends on the retail type - clothing shops differ from food retail.

Retail Fit-out Electrical Costs (2024)

Typical UK installation costs for retail electrical fit-outs.

Installation Scenario	Materials	Labour	Total
Basic shop fit-out (<50m²)	£1500-3000	£2000-3500	£3500-6500
Medium retail fit-out (50-100m²)	£3000-6000	£4000-7000	£7000-13000
Shop lighting installation	£1000-2500	£1500-3000	£2500-5500
Emergency lighting system	£500-1200	£600-1200	£1100-2400
Three-phase upgrade	£1500-3000	£1000-2000	£2500-5000

Prices as of 2024. Costs vary by unit size, specification, and starting condition.

Commercial Lighting Levels

Retail lighting is critical for product display and customer experience. General retail needs 300-500 lux, with accent lighting for displays reaching 750-1000 lux. This translates to significant electrical load - typically 15-25W/m² for modern LED retail lighting. Lighting circuits often represent 30-50% of shop electrical load.

Retail Electrical Load Diversity

Retail loads vary throughout the day - peak during trading hours with all lighting, minimal overnight. When calculating maximum demand, apply diversity: 90% for lighting (usually all on together), 50-70% for sockets (not all used simultaneously). This helps right-size the supply without over-specifying.

Shell and Core vs Cat A vs Cat B

Retail fit-outs have different starting points. Shell and Core: basic structure only, install everything. Cat A: landlord provides basic services to demise. Cat B: tenant fit-out of Cat A space. Electrical scope varies dramatically - understand your starting point before quoting.

Frequently Asked Questions

Related Electrical Calculators

Commercial Kitchen

Food retail and cafés

CCTV & Security

Retail security systems

Voltage Drop Calculator

Check distribution runs

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