Short answer: most live data centres survey their critical power chain (switchgear, UPS, busbar and PDUs) at least once a year under normal load, and every six months on high-criticality, older or heavily loaded sites. The survey should be done by a certified thermographer, Level 2 or above, ideally independent of the maintenance contractor, with Level 3 oversight.
Once a year is the floor, not the target
An annual survey is what insurers and FM contracts commonly ask for, and it is a sensible minimum. But a data centre is not a static building. Halls fill up, IT load climbs, and connections that were fine at handover end up carrying far more current than they did on day one. How a connection behaves can change a lot within a year as load rises.
That is why many operators survey critical infrastructure every six months. The second survey of the year is not a repeat of the first: it is a check on whether last time’s findings were fixed, and whether anything new has appeared as the load profile changed.
When to survey more often
- In the first year after handover, when a new installation settles and halls are being populated
- After a significant load increase, a new customer fit-out or a change to the power chain
- After major works, such as a UPS replacement or new busbar runs
- On older switchgear, or where a previous survey found connections that need watching
- Where the site’s own risk assessment or a client SLA asks for it
Timing matters as much as frequency
Thermography finds faults by the heat they produce, and that heat depends on current. A survey at light load can miss a poor connection that would show clearly at normal load. We aim to survey at normal operating load, ideally 40% or more, and record the load against every finding so results can be compared fairly from one survey to the next.
On a dual-fed site, the A and B chains are surveyed in turn. Surveys can be phased by hall or run out of hours to fit the site’s maintenance windows. See how we plan annual PPM thermography for data centres.
Who should do the survey
The person holding the camera matters. Thermographers are certified in levels (to ISO 18436-7 through bodies such as the ITC):
- Level 1 can capture images and follow a set procedure.
- Level 2 can plan and carry out a survey, take account of emissivity, reflections and load, and write the report.
- Level 3 sets procedures, oversees programmes and makes the final call on grading.
For a data centre, look for Level 2 or above on site and Level 3 oversight of the programme. Independence helps too: a surveyor who does not carry out the repairs has no reason to under- or over-state a finding. Ti inspects and reports only. Our thermographers are ITC Level 3 and Ti is a Level 3 certified company.
The survey team should also work within your permit-to-work and method statements. On our surveys, your authorised electrician opens and closes panel covers, and our thermographer does not touch live equipment.
Start the clock at commissioning
The best first survey is the one done during commissioning load testing, before the site goes live. It gives every joint a baseline that annual surveys can be compared against.
On a London data centre build, commissioning thermography during busbar load testing found 16 busbar sections running above 80°C under test load. The hottest point, at a tap-off unit, measured 103.5°C. Each one was reported with its location and matching thermal and visual images, so the installer could investigate before handover. Read more on thermal imaging busbars during commissioning.
What each survey should give you
- A thermal image and matching photo for every finding
- The exact location: hall, room, panel and circuit
- The measured temperature, the load at the time, and a severity grade with a recommended action and timescale
- A comparison with the previous survey, so trends are visible
We cover switchgear, busbar, UPS, PDUs and ATS. See our data centre electrical thermography page, our switchgear thermography page and the 7 electrical risks that cause data centre downtime.
Frequently asked questions
Is thermography a legal requirement for UK data centres?
No single UK regulation names thermography. The Electricity at Work Regulations 1989 require systems to be maintained to prevent danger, and thermography is one of the ways sites show that. Insurers and client contracts often ask for it specifically.
Does a thermographic survey replace the EICR?
No. An EICR is a periodic inspection and test of the installation. Thermography looks at how connections behave under real load. They answer different questions and work best side by side.
Do we need a shutdown for the survey?
No. Thermography is non-contact and needs the equipment energised and under load, so the site stays live throughout.
Talk to us: +44 20 3885 7464 · sales@thermalimaging.co.uk · send us your site details
About the author: Rachael Browning is General Manager of Ti Thermal Imaging, which carries out electrical thermography surveys for data centres, FM portfolios and industrial sites across the UK and UAE. Ti’s work has featured on BBC News and ITV.