Can rack PDUs be thermally imaged in a live data hall without disturbing the IT load?

Yes. Rack PDUs can be thermally imaged in a live data hall with the IT load running and nothing unplugged or switched. The thermographer images the inlet connector, the PDU body and the outlet sockets from the rear of each rack once site staff open the doors, and records the PDU’s current reading with each image where shown.

What gets imaged at the rack

A rack PDU is the last link in a chain that starts at the switchboard. On a rack survey we image:

The inlet plug and socket where the PDU takes its supply
The PDU body along its length, including any breakers or fuses built into it
The outlet sockets and the plugs sitting in them
The supply cable back to the floor PDU or busbar tap-off, which is usually surveyed in the same visit

Each rack is recorded by its own reference and by feed (A or B), so the operations team can find every finding on the floor without a guide.

Why nothing needs switching off

Thermography is non-contact. The survey looks at the equipment as it runs, which is the point: a connection only shows its true condition when it carries current. Our thermographers don’t unplug anything, move cables or touch IT equipment.

Perforated rack doors block a clear view, so they need to be opened for a few moments at each rack. That is normally done by or with the site’s own team, under the site’s change process and escort rules. Where cable management hides an inlet or a bank of outlets, we report it as not visible rather than move anything.

The hot aisle trap

The rear of a rack sits in server exhaust air, so everything there is warm. An absolute temperature on its own says very little. What matters is the comparison with like for like: the same PDU model on neighbouring racks, matching outlets on the same PDU, and the other feed on the same rack, allowing for any difference in load between them. Every finding is reported as a measured temperature, where it was taken, and the difference in °C from its reference.

Load matters, and data halls often run light

Many halls run well below their design load, especially in the first years after handover. A connection that is fine at low load can show up as the hall fills. So we record the current at the time where the PDU displays it, say plainly in the report when a reading was taken at low load, and suggest repeating the rack survey when the load in that hall has grown.

What the report shows

For each finding: rack reference, PDU and feed, a thermal and visual image, the measured temperature and the exact point it was taken, the comparison and difference in °C, and the load at the time. Ti inspects and reports; the client’s electrical team or contractor investigates and carries out any work. Reports are usually issued the same or next working day.

The same approach runs through our commissioning work. On one London data centre build this autumn, our commissioning thermography recorded 16 busbar sections reading above 80 °C under test load, the highest 103.5 °C at a tap-off unit. Imaging the busbar, tap-offs and rack PDUs as one survey gives the operator a single, joined-up record from switchboard to rack.

Frequently asked questions

Do the racks need to be opened?

Perforated doors are opened briefly so the camera has a clear view. Site staff usually open them; we never touch the IT equipment inside.

Can rack PDUs be surveyed at the same time as the switchgear and UPS?

Yes. Switchboards, UPS, busbar, tap-offs and rack PDUs can be covered in one visit, so the report follows the power path end to end.

How often should rack PDUs be surveyed?

Many operators include them in the annual electrical thermography survey, with an extra rack survey when a hall’s load rises noticeably.