Can thermography check the underfloor power in a raised-floor data hall?

Short answer: partly. With floor tiles lifted under the site’s permit, a thermographer can image the underfloor connections you can see and reach safely: tap-off units on underfloor busbar, plug-and-socket connectors and junction boxes feeding the racks, with the IT load running. Cable runs hidden in the void, and anything under tiles that stay down, are listed as not seen.

What sits under a raised floor

Newer halls often run power overhead. Many older and mid-life halls still run it under the floor: underfloor busbar with tap-off units, flexible cable assemblies with plug-and-socket connectors at each end, and junction or distribution boxes fixed to the floor slab. Every rack in the row depends on them, and they are out of sight for most of the year.

Because nobody sees them on a walk round, they are easy to leave out of a survey scope that covers the switch room, the floor PDUs and the racks.

Who lifts the tiles, and how many

Tiles are lifted by the site’s own team or authorised person, under the site’s permit. In a hall that uses the floor void for cooling air, an open tile changes the airflow, so agree up front how many tiles can be open at once, usually a short run along one row, replaced before the next run is opened.

The thermographer images through the open tile from above. Nobody needs to go into the void.

What is imaged, and what is not

Imaged: tap-off units and their connection to the busbar, plug-and-socket connectors, junction box terminals where the cover can be removed safely, and the cable either side of each connection that is in view.
Not imaged: cable buried in the void out of line of sight, connectors under tiles that stay down, and anything behind a cover that cannot come off safely.

The report lists every location that was not seen. It never calls an unseen connector clear.

Reading the images honestly

Under-floor kit sits among galvanised pedestals, trays and bare metal, which reflect heat from elsewhere. Readings are taken from surfaces that give a true reading, compared like for like with a matching connector on a similar load, and the load is recorded with each image. Findings are given as the measured temperature and the difference in °C, with the floor grid reference so your team can find the tile again.

Best at commissioning, then every year

The easiest time to see underfloor connections is before the racks are fully in and cabled. On one London data centre build, Ti’s commissioning thermography found 16 busbar sections over 80°C under test load, the highest reading 103.5°C at a tap-off. They were found while the hall was still under test. After handover, underfloor locations join the annual survey, a section of rows at a time if needed.

Frequently asked questions

Does lifting tiles affect cooling?

It can, which is why the number of open tiles is agreed with the site first and each run is closed before the next is opened.

Does any IT load need switching off?

No. The survey is done live, at normal load. Nothing is unplugged or switched.

Can every underfloor connection be covered in one visit?

Not always. Large halls are often split across visits, and the report shows which rows were covered and which locations were not seen.