A refrigerated container does not plug in like a shop fridge. Whatever the make of its refrigeration unit — Carrier, Thermo King, Daikin or Star Cool — a full-size reefer almost always expects a three-phase 380/400 V supply through an industrial five-pin 32 A CEE plug. The classic surprise is a delivered unit that nothing on site can power. This guide sets out refrigerated container power requirements for a UK site — the standard connection, the single-phase exceptions, generators, and the electrician’s sign-off to arrange before delivery day.
The standard: three-phase 380/400 V and a 32 A CEE plug
Reefers were designed for ships and container terminals, and that heritage survives on land as the red five-pin CEE connector: three phases, a neutral and an earth, rated at 32 A and fed with three-phase 380/400 V.
To receive one, your site needs:
- a three-phase supply with 5 to 12 kW available, depending on the size of the unit and the set point;
- a five-pin 32 A CEE socket fitted close to where the container will stand;
- a dedicated circuit with its own breaker, RCD protection and a verified earth;
- cable sized for the run — the longer the distance back to the board, the larger the conductor needed to limit voltage drop, and that is an electrician’s calculation, not a guess.
Most units arrive with their own lead and CEE plug fitted; check its length at quote stage — a container sited far from the distribution board is a different job from one backed against the building.
The single-phase question
Search for a single phase refrigerated container and you will find genuine confusion, because the market splits in two. Compact units and most mobile cold rooms are built for 230 V single phase — plenty of shops, pubs, butchers and farm buildings have no three-phase supply at all. Full-size 20ft and 40ft reefers, by contrast, are three-phase machines with no practical way around it.
Two cautions. First, the plug fitting is not standardised as it is on three-phase units: 13 A, 16 A and 32 A single-phase connections all exist, so confirm the exact plug and current draw with the supplier before booking. Second, a dedicated circuit is still non-negotiable — a refrigeration unit has no business on an extension lead or a shared socket.
If your requirement fits in roughly 15 m³ — a 10ft unit or mobile cold room, four to five pallets — single phase is often the shortest route to cold storage.
How much power the unit draws
Allow 5 to 12 kW depending on the format and the duty. A standard reefer operates anywhere across -25 °C to +25 °C, and frozen duty at -18 °C draws more than chilled duty at +2 °C on the same machine.
| Format | Usable space | Typical connection |
|---|---|---|
| 10ft | ~15 m³, 4–5 pallets | Three-phase; 230 V single-phase versions exist |
| 20ft | ~28 m³, 10–11 pallets | Three-phase, 32 A CEE |
| 40ft high cube | ~67 m³, 23 pallets, 2.55 m internal height | Three-phase, 32 A CEE |
The catch is the start-up surge: a compressor briefly draws well above its nominal load each time it starts, and a supply sized to the running load alone will trip repeatedly. Build in margin and have the final figure confirmed.
Consumption is the other half of the power question: budget for 70 to 170 kWh a day depending on size and set point. Over a hire of any length — indicative long-term rates start at around £12 a day ex VAT, with VAT at 20% — electricity can end up rivalling the hire rate itself. Our running costs guide breaks that down.
No three-phase on site: three routes
A small single-phase unit. If the volume works, this is usually the fastest fix for the small commercial sites that lack three-phase in the first place. The hire market is worth understanding first, though: minimum terms of around 90 days are common in the UK, even if some suppliers do offer short-term hire.
A generator. On a construction site, an event field or anywhere off-grid, a three-phase generator is the established answer. Two imperatives: margin over the start-up surge, and genuinely continuous running — cold storage does not forgive long interruptions. Fuel goes in the operating budget, and sizing is agreed with the generator supplier and your electrician.
A supply upgrade. For a permanent installation, asking your distribution network operator for a three-phase connection is the durable answer. It takes time and the cost varies with the site, so start the process when you order the container, not the week it arrives.
Commissioning and electrician sign-off
Have a qualified electrician sign off the installation before the first chill-down. In one visit they will confirm the available capacity, the breaker and RCD protection, the earth, the cable size against the length of run, and the CEE socket itself. The reason is blunt: an improvised connection can destroy a compressor, spoil a container full of stock overnight, and give an insurer grounds to refuse the claim. On a used unit — observed at £4,500 to £7,500 ex VAT in the UK — a wrecked refrigeration unit can be worth more than the container; if you are buying used, ask for a PTI (Pre-Trip Inspection) test under three months old too.
Before delivery day, the checklist reads:
- three-phase 380/400 V available at the pad, or the single-phase or generator alternative confirmed;
- a 32 A CEE socket — or the agreed single-phase connection — on a dedicated, protected circuit;
- the unit’s own lead long enough to reach the supply point;
- margin in the supply for the compressor’s start-up surge;
- firm, level ground that will carry the unit loaded;
- the electrician booked ahead of the first chill-down.
If any line is unresolved, move the delivery. An unpowered reefer is just an insulated box, and stock does not wait.
Ask the power question at quote stage
Whether you are hiring for a season or buying outright — new one-trip units are observed at £18,995 to £22,500 ex VAT — raise the electrical question in the first conversation: what supply the site has, which format fits it, how long a lead you need. Set it out once in a quote request and we pass it to specialist suppliers, who contact you directly if they can meet your need. For the wider picture on costs, sizes and buying used, browse all our guides.
Frequently asked questions
What power supply does a refrigerated container need?
Almost all full-size refrigerated containers run on a three-phase 380/400 V supply through an industrial five-pin 32 A CEE plug — three phases, a neutral and an earth. Allow 5 to 12 kW of available power depending on the size of the unit and the set point, plus a margin for the compressor's start-up surge. Some small formats run on 230 V single phase, but treat that as the exception and check the data plate.
Can I run a refrigerated container on single phase?
Only on certain small formats. Some compact units and most mobile cold rooms are built for 230 V single phase, and their plug fittings vary from machine to machine, so confirm the exact connector with the supplier before ordering. Standard 20ft and 40ft reefers need three-phase power. If your site only has single phase and you need full-size capacity, the realistic options are a generator or a supply upgrade.
Can a generator power a refrigerated container?
Yes, provided it delivers three-phase 380/400 V and is sized with a comfortable margin over the unit's nominal draw, because the compressor's start-up surge is well above its running load. The generator must also run continuously — a prolonged stop lets the temperature climb — and fuel belongs in your operating budget. Have the sizing confirmed by the generator supplier and an electrician before the first chill-down.
Do I need an electrician to sign off the connection?
Yes, without exception. A qualified electrician confirms the available capacity, the cable size against the run back to the board, RCD protection, earthing and the CEE socket itself in a single visit. An improvised connection risks three losses at once: the refrigeration unit, the stock inside, and your insurance cover if a claim follows. Book the visit before delivery, not after the unit is sitting on site unpowered.
How much electricity does a refrigerated container use?
Budget for roughly 70 to 170 kWh a day in the UK, depending on the size of the unit and the set point — frozen duty at -18 °C draws more than chilled duty at +2 °C on the same machine. Door openings, ambient temperature and how full the unit is all move the figure. Over a long hire, electricity can rival the hire rate itself, so price the two together.