Refrigerated containers
Reefer container power cables and plugs
A refrigerated container keeps its cargo safe only while it has power. The lead and plug that deliver that power are handled roughly, dragged across quays and decks, and exposed to salt water. They deserve a better specification than they usually get.
How a reefer is powered
Refrigerated ISO containers, covered by ISO 1496-2 for thermal containers, carry their own refrigeration unit. That unit runs on three-phase AC supplied by the ship, the terminal's reefer racks, a clip-on generator set or a depot supply. The unit carries its own power lead, stored on the container when not in use, and ending in an industrial plug.
Most reefer units use a four-pin (three-phase plus earth), 32 A plug from the IEC 60309 industrial plug family, color-coded red for the 380–480 V range. IEC 60309 plugs are keyed by the position of the earth contact as well as by color. Always confirm the voltage range, rating and earth-contact position against the refrigeration unit maker's documentation and the receptacles at your terminals before ordering replacements. Reefer plugs use the 3h earth position that IEC 60309-2 reserves for refrigerated containers, not the 6h position of most land-side 400 V equipment; the reefer plug guide explains the difference.
Where the lead gets plugged in
| Location | Supply | What it means for the lead |
|---|---|---|
| Ship | Reefer sockets in holds and on deck | Salt exposure, long periods plugged in, tight stowage |
| Terminal | Reefer racks and plug-in areas | Frequent plugging and unplugging, leads laid on the ground, traffic nearby |
| Road or rail | Clip-on or undermount generator set | Vibration, and the lead must be secured so it cannot drag or disconnect in transit |
| Depot or cold store | Fixed electrical installation | Designed and inspected by a qualified electrician to local regulations |
Chassis builder CIE Manufacturing describes gensets supplying reefers at 460 V, 60 Hz, and advises securing the power cable with hangers or ties so it cannot come loose in transit, and checking both ends for corrosion, wear and bent pins before connecting.
How reefer leads fail
- Crushed or cut jackets from handling equipment, lashing gear and container doors.
- Damaged plugs that are dropped, dragged or left unplugged on the ground, with bent pins, cracked housings and failed seals.
- Water in the plug when the cover is left open or the gland seal has hardened, leading to corrosion and tripped supplies.
- Pulled terminations where the lead has been yanked out by the cable instead of the plug, and the strain relief has let go.
- Jackets hardened or cracked by sunlight, cold and repeated coiling.
A failed lead can mean a warm container and a cargo claim, so leads and plugs are inspected at every pre-trip inspection (PTI). Damaged leads should be replaced, not taped.
Specifying a replacement lead
| Item | What to specify |
|---|---|
| Cable type | Heavy-duty flexible cable rated for outdoor and marine exposure, with an oil- and weather-resistant jacket. Rubber-insulated flexible cable such as the H07RN-F type is widely used, but follow the unit maker's specification. |
| Conductors | Three phases plus earth, sized for the unit's current and the lead length. |
| Length | Match the original so it reaches rack receptacles in every stowage position, without leaving excess cable to be damaged. |
| Plug | Same IEC 60309 rating, voltage color and earth position as the terminal and ship receptacles, with a watertight rating suitable for exposed use. |
| Unit end | The termination method and gland specified by the refrigeration unit maker. |
| Strain relief | At both ends, rated for the pull the lead will actually see. |
| Test | Continuity, correct phase-to-pin order, earth continuity and insulation resistance on every lead. |
| Identification | Part number and date, so leads that fail early can be traced to a batch. |
Extension leads and depot wiring
Depots and cold-storage yards often build their own extension leads and distribution boards for reefer plug-in areas. These are fixed or semi-fixed electrical installations. They must be designed and inspected by a qualified electrician to the local wiring regulations. Buy the leads to the same specification as above, and never join two leads with an unsealed coupling on the ground.
Common questions
How long is a reefer power cable?
Lengths vary by unit maker. Container supplier Cascade Container, for example, describes its reefers as equipped with an 18 m (59 ft) 460 V cable. Replace like for like so the lead reaches receptacles in every stowage position you use.
What cable is used for reefer leads?
Heavy-duty flexible rubber cable is common. The harmonized H07RN-F type, covered by EN 50525-2-21, is widely used for outdoor industrial power leads. The refrigeration unit maker's specification governs, including conductor size.
Can a damaged reefer lead be repaired?
Replace damaged leads rather than taping or splicing them. A lead is handled daily and lies on wet surfaces, and a repair that lets water in is a safety hazard as well as a reliability problem.
Why test phase order?
A lead with two phases swapped reverses the rotation of three-phase motors. Test phase-to-pin order on every new or re-terminated lead.
Jacket materials for leads that live outdoors are compared in PVC vs PUR vs TPE cable jackets.
Tracking the leads themselves. Operators that log lead replacements against container numbers spot problem stowage positions and handling practices quickly. It is a small maintenance record that pays for itself, and exactly the kind of per-unit history Cargovate keeps alongside the container's movements.
Last reviewed 2026-09-17