Should a data centre's thermography survey be done before or after the annual UPS and switchgear maintenance?

Short answer: before, in most cases. A live survey a few weeks ahead of the annual maintenance window, at normal operating load, lets any hot connection be added to the maintenance scope and put right in the shutdown you have already planned. Anything remade during that window is then re-imaged once it is back under normal load.

Why before usually works best

Thermography needs current flowing. In a live data centre the best time to image UPS input and output connections, switchboards, static transfer switches and busbar tap-offs is at normal operating load, with nothing on bypass and no load transferred.

The annual UPS and switchgear service is the opposite: load is moved, systems go to bypass and sections are isolated so the maintenance contractor can work. That is the right moment to remake a connection, and the wrong moment to look for one.

Surveying first means the maintenance contractor arrives with a list. A finding at a UPS output terminal or an incomer goes into the work already planned for that window, with the parts and permits sorted in advance, instead of needing a second outage later.

Why straight after is not enough on its own

A survey the day after the service often sees very little. Load may still be on bypass or split differently from normal, and the connections have just been disturbed. Imaging them at low or unusual load can give a clean result that says nothing about how they behave in normal running.

What does make sense after the window is a targeted re-image: the connections that were remade, imaged again once normal load is back, so the record shows the work made a difference.

How far ahead to survey

Far enough ahead for the maintenance contractor to plan, close enough that nothing much changes in between. Agree the gap with your maintenance contractor and change manager. Keep the survey outside any change freeze, and outside any period where load has been moved for other work.

If the annual survey date is fixed by an insurer or a customer contract, line the maintenance window up behind it rather than the other way round.

What the maintenance contractor gets

Each finding comes with a thermal image and a matching photo, the measured temperature, exactly where it was taken, the load at the time, and the difference in °C from a matching phase or identical unit. Asset references are taken from your own CMMS, so the item drops straight into the maintenance scope.

Ti inspects and reports. Your maintenance contractor carries out the work, and the re-image confirms it.

Finding it before it matters

The same logic applies at commissioning. 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 and reported while the hall was still under test, when putting them right was part of the programme, not once customers were live.

Frequently asked questions

Can the maintenance contractor do the thermography during the service visit?

The service visit is usually the wrong load condition for it. Many operators also prefer an independent thermographer, so the people checking the connections are not the people who made them. More on that choice.

Does torque checking during the service replace thermography?

No. A torque check confirms a bolt is tight at that moment. Thermography shows how the whole connection behaves under load, including parts a torque wrench does not test.

What if the survey finds something that can’t wait for the window?

The report says so on the day, and your change process decides the next step. What happens when a board can’t be isolated yet.

Should a data centre’s thermography survey be done before or after the annual UPS and switchgear maintenance?