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.
Electrical connection
The cheapest option to run if your site already has a three-phase distribution board within 50 m of where the reefer will stand. The dedicated plug is a red five-pin CEE plug to IEC 60309.
CEE Plug 32 A (standard reefer)
Suits most 20ft and 40ft reefers in regular use. Delivered power 22 kW. 5G6 cable (five 6 mm² conductors) for runs up to 50 m. Connection to an existing board: £315 – £840 (materials and electrician’s labour), to be confirmed by a competent electrician.
CEE Plug 63 A (deep freezing, park)
Required for deep-freeze 40ft units or several reefers in parallel from the same enclosure. Power 43 kW. 5G16 cable for runs over 30 m. Connection cost: £840 – £2,100. Check the supply capacity with your network operator.
If there is no three-phase supply on site, ask the local network operator for a new connection before ordering the reefer: timescales and the cost of any network extension depend on the site. Indicative cost for a standard connection: £1,050 – £5,250, to be confirmed by the operator.
Dimensioning kVA: reference table
To choose the supply capacity from the network or a generator, work in apparent power (kVA), which includes a margin for compressor start-up peaks and hot weather (condenser overload at +30 °C ambient).
| 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 |
Rule of thumb: size the generator at twice the reefer’s nominal power, to absorb the start-up peak and a summer heat 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 = £945 – £1,890 in diesel fuel. Plan for a 500-1 000 L fuel tank + strict refuelling schedule.
Generator Rental Cost
15 kVA: £84 – £126/day. 25 kVA: £126 – £189/day. 50 kVA: £210 – £368/day. Some reefer rental companies offer packages « reefer + generator + initial fuel » at a decreasing rate — saving 15-25 % compared to separate rentals.
Noise Pollution
Check manufacturer sound data and measurement conditions, siting and local noise or event-permission rules. Hours and limits are not universal. Plan separation, acoustic screening and maintenance while preserving ventilation and safety.
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) | +£3,150 – £8,400 vs standard reefer | Variable compressor, reinforced insulation |
| Solar panels (4-8 kWc) | £6,300 – £15,750 | Surface 25-50 m² roof or ground |
| Lithium battery (10-20 kWh) | £8,400 – £21,000 | Autonomy night + covered days |
| Inverter + regulation | £2,100 – £5,250 | 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 an ordinary 230 V domestic socket?+
No. A reefer needs a 400–415 V three-phase supply (BS 7671). A single-phase domestic socket delivers no more than about 3.5 kW, not enough to start a refrigeration compressor, which needs 8–15 kW at start-up. A makeshift adapter means the breaker trips at every cycle, the compressor wears out and your insurance will not cover an electrical incident.
What is the difference between 32 A and 63 A three-phase?+
A 32 A supply (red five-pin CEE plug) delivers about 22 kW of usable power: enough for a 20ft reefer at chilled temperatures or a 40ft unit in normal use. A 63 A supply (larger red five-pin CEE plug) delivers about 43 kW, needed for deep-freezing with high start-up peaks on a 40ft container or to run two or three reefers in parallel. Upgrading the connection from 32 A to 63 A costs more: ask the network operator for a quote.
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 £0.21/kWh commercial rate : £13 – £50/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?+
Calculation scenario to replace with generator data and a current local price: assuming 3–6 L/h for 24 hours gives 72–144 L/day. At an assumed 1.20–1.40 £/L, fuel alone is around 86–202 £/day, or 860–2 020 £ over ten days. This is neither an observed local price nor guaranteed consumption. Load, setpoint, weather, operating hours and generator alter the result; confirm autonomy, reserve and refuelling, and local fuel-storage rules.
Do I need a qualified electrician to connect it?+
Yes: have a competent electrician make and check the three-phase connection to BS 7671, against the equipment rating plate and the network operator’s requirements. Cost: £315 – £840 for a simple connection (CEE socket on an existing board), £1,575 – £4,200 for a new dedicated three-phase board. Keep the electrician’s certificate: insurers may ask for it after an incident.
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