Electrical supply for a refrigerated container
A poorly connected reefer = compressor wears out prematurely, cold chain breakage, and insurance decline coverage. This guide details the three connection options (three-phase grid, generator, solar), kVA sizing by format, and the most common technical pitfalls.
Option 1 — Three-phase 415 V (BS 7671) grid connection
The most economical option in use if your site already has a three-phase panel within 50 m of where the reefer will be placed. The dedicated plug is a red CEE five-pin plug, IEC 60309 standard (inter-European).
CEE Plug 32 A (standard reefer)
Covers 95% of refrigerated containers 20 and 40 feet in regular use. Delivered power 22 kW. Cable 5G6 (five conductors of 6 mm²) for distances up to 50 m. Connection cost on existing panel: £315 – £840 (material + electrician labour).
CEE Plug 63 A (deep freezing, park)
Required for 40 feet deep freeze or multiple reefers in parallel from the same enclosure. Power 43 kW. Cable 5G16 for distances > 30 m. Connection cost: £840 – £2,100. Note: Enedis subscription > 36 kVA costs +80-£130/month compared to 36 kVA.
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Dimensioning kVA: reference table
To choose between an electricity supply agreement with Enedis or a generator, calculate in apparent power (kVA), which includes the margin for compressor start-up peaks and summer surcharges (condenser overload at +30 °C ambient temperature).
| Format / usage | Nominal power | Start-up peak | Recommended generator | CEE socket |
|---|---|---|---|---|
| 20 feet refrigeration (+2 to +8 °C) | 3-5 kW | 8-10 kW | 15 kVA | 32 A |
| 20 ft refrigerated container (-18 to -25 °C) | 5-7 kW | 10-12 kW | 20 kVA | 32 A |
| 40 ft refrigerated container | 4-7 kW | 10-12 kW | 20 kVA | 32 A |
| 40 ft HC refrigerated container | 6-8 kW | 12-15 kW | 25 kVA | 63 A |
| Reefers park of 3 units | 12-20 kW | 25-35 kW | 50 kVA | Tableau 63 A |
| Reefers park of 5-8 units (logistics) | 25-50 kW | 50-80 kW | 80-125 kVA | dedicated dashboard |
Overdimensioning rule: generator power = 2× nominal reefer power to absorb start-up peak + summer thermal margin.
Option 2 — Autonomous Generator Set
Essential when there is no three-phase power available on site: festival, isolated construction site, remote agricultural operation. The diesel generator remains the most flexible solution, but involves a real logistical commitment (fuel, maintenance, noise).
Fuel Consumption
3-6 L/h at 60-70 % load. That is 70-145 L/day continuously. For a 10-day festival: 700-1 450 L = £900-£1 800 in diesel fuel. Plan for a 500-1 000 L fuel tank + strict refuelling schedule.
Generator Rental Cost
15 kVA: £80-£120/day. 25 kVA: £120-£180/day. 50 kVA: £200-£350/day. Some reefer rental companies offer packages « reefer + generator + initial fuel » at a decreasing rate — saving 15-25 % compared to separate rentals.
Noise Pollution
Modern professional generators with soundproofing: 65-75 dB at 7 m. Sufficient for construction sites / festivals, but may be an issue in residential urban areas (neighbourhood noise regulation after 10 pm). Prefer a « silent » model at +20-30 % cost.
Option 3 — Autonomous Solar Power (humanitarian or low-carbon pro case)
Emerging option, mainly used in humanitarian contexts (MSF, Red Cross) and organic agricultural operations. Solar panels + buffer battery + low-consumption specific reefer. More expensive upfront but total autonomy — no fuel, no connection.
| Item | Range | Note |
|---|---|---|
| Low consumption reefer (2-3 kW) | +3,000-£6,800 vs standard reefer | Variable compressor, reinforced insulation |
| Solar panels (4-8 kWc) | 6,000-£13,000 | Surface 25-50 m² roof or ground |
| Lithium battery (10-20 kWh) | 8,000-£17,000 | Autonomy night + covered days |
| Inverter + regulation | 2 000-5 000 € | Three-phase, IoT monitoring |
| Total extra | £19,950 – £50,400 | Payback period 4-8 years vs diesel |
Interesting solution for continuous use > 2 years in off-grid areas. Not profitable for occasional use (festival, short season) where renting a diesel generator remains unbeatable.
Frequently Asked Questions
Can you plug a reefer into a domestic socket at 220 V?+
No, never. A reefer requires three-phase power 400-415 V (BS 7671) absolutely. A single-phase domestic socket at 220 V / 16 A delivers only 3.5 kW peak, insufficient to start a refrigeration compressor which needs 8-15 kW at startup. Attempting an unauthorised connection with adapter = circuit breaker trips every cycle, compressor damaged over time, and your insurance will not cover any electrical incident.
What is the difference between 32 A and 63 A three-phase?+
The 32 A (CEE red plug, five pins) delivers around 22 kW of usable power — sufficient for a 20-foot reefer in positive refrigeration mode or a 40-foot unit in regular use. The 63 A (larger CEE red plug, five pins) delivers approximately 43 kW — necessary for deep freezing with high startup peaks on a 40-foot container or to power two to three reefers in parallel. Connection cost with Enedis higher (+500-£1,300 to upgrade from 32 A to 63 A).
How much does a reefer consume per day on average?+
Depends on the set temperature, external temperature and door opening frequency. Refrigeration +2 to +8 °C (standard food industry) : 60-120 kWh/day for a 20 ft container, 90-160 kWh/day for a 40 ft container. Freezing -18 to -25 °C : 120-180 kWh/day (20') and 160-240 kWh/day (40'). At £0/kWh commercial rate : £10-£40/day of electricity consumption. Double in summer with strong external heat.
What generator power should I choose?+
Sizing rule: nominal reefer power × 2 to absorb start-up peaks and thermal margin for summer. A 20 ft refrigeration unit (4-5 kW nominal) can manage a 15 kVA generator. A 40 ft freezing unit (7-8 kW nominal) requires at least a 25 kVA generator. For a fleet of 3-4 reefers: 50-80 kVA centralised generator. Under-sizing = repeated tripping, premature compressor wear. Over-sizing = unnecessary fuel consumption.
How much fuel does a 20 kVA generator consume?+
Approximately 3-6 L/h of diesel at medium load (60-70%). That is 72-144 L/day in continuous operation. At non-road diesel price 2025 (£1.20-£1.40/L) : £85-£200/day fuel cost. For a 10-day festival, expect £1,000-£2,000 of fuel for a reefer + generator. Anticipate a reserve tank of 500-1,000 L and refuelling schedule — running out of fuel mid-festival can ruin the cold chain.
Do I need a qualified electrician to connect it?+
Yes, mandatory for all professional three-phase connections. NF C 15-100 article and labour law require that commercial or industrial three-phase connections be made by a certified electrician. Cost: £315 – £840 for a simple connection (CEE plug on existing board), £1,575 – £4,200 for dedicated three-phase board installation. In case of damage, lack of Consuel certificate may block insurance compensation.
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