Should reefer container power points be included in an electrical thermography survey?

Yes. Reefer power points supply refrigerated containers around the clock, outdoors, through plugs and sockets that are connected and disconnected every day. The survey should cover the reefer distribution boards, feeder pillars and the socket outlets in use, imaged while containers are plugged in and running, with the occupancy and load recorded for each stack.

This applies to container ports and terminals, rail freight terminals, inland depots and cold-chain distribution yards. Reefer supplies often sit between scopes: the main switchboard is in the site’s survey, the containers belong to their owners, and the stacks in between are nobody’s job.

What to include

The LV boards and feeders that supply the reefer area.
Reefer distribution boards and feeder pillars at each stack or row, opened by the site’s authorised electrician.
Socket outlets with a container plugged in and running, imaged from the outside at the plug and socket.
Any associated boards for lighting towers, gate equipment or monitoring in the same area.

The containers themselves, and anything on the HV side, sit outside the scope.

Timing: occupancy decides the load

An empty socket carries no current and shows nothing. Book the survey for a period when the stacks are busy, and ask the terminal for an occupancy plan on the day so the route follows the occupied rows. Refrigeration units cycle, so the thermographer may need to wait at a stack or return to it. The report records how many points were in use and the load on each board when it was imaged (see what load a survey needs).

Outdoor traps

Sun. Metal housings and pillars warm up in direct sun, one face more than another. Night or overcast conditions give cleaner readings, and reefer load carries on through the night.
Wind and rain. Both cool surfaces and can hide a warm connection. Readings taken in poor weather are noted as such (see outdoor surveys in UK weather).
Exhaust heat. A container’s condenser blows warm air. If it plays across a socket, the socket can look warm for reasons that have nothing to do with the connection.
Shiny metal. Stainless and galvanised surfaces reflect heat from elsewhere, so the angle of each image matters.

Access and safety

Terminals have heavy vehicles moving between the stacks. Agree the route, the escort and any lane closures with the terminal before the day, and work to the site’s induction and PPE rules. The survey is non-contact: the thermographer never plugs or unplugs a container.

What the report gives you

Each finding is located by stack, row and socket or board, with a thermal and visual image pair, the measured temperature, where it was taken and the difference in °C from the matching reference. A not-imaged list shows the points that were empty on the day. We deliver reports the same day. Ti inspects and reports; the site’s electrical contractor investigates any finding with the circuit isolated.

Why the method matters

Connections show their condition only when they carry current. On a London data centre build, commissioning thermography by our team found 16 busbar sections reading above 80 °C under test load, the highest 103.5 °C at a tap-off unit. Different equipment, same rule: image it working (see busbar thermography at commissioning).

Frequently asked questions

Do the containers need to be plugged in?

Yes. Only sockets supplying a running container carry current. Empty points are listed as not imaged.

Can the survey be done at night?

Often it is the better choice. Reefer load continues overnight and there is no sun on the housings. Lighting and access need agreeing with the terminal.

Who opens the reefer boards?

The site’s authorised electrician, under the site’s own permit system (see who opens the panels).