How long does an electrical thermography survey take, and what decides it?

It depends on how many panels need opening and how easily the thermographer can get to them, not on the size of the building. Imaging a board is quick once its cover is off. Most of the time goes on opening and closing panels, moving between plant rooms and catching each area at load. Smaller sites are often one visit; large data centres and portfolios run over several days.

What actually takes the time

People expect the camera work to be the slow part. It isn’t. The day is set by everything around it:

Opening panels. Covers are removed by the site’s electrician or an authorised person, one at a time, under the site’s own safe system of work (see who opens the panels). If one electrician is shared with other jobs, the survey moves at their pace.
Getting around the site. Plant rooms on the roof, switch rooms in the basement and boards in risers on every floor all add walking, keys and sign-ins.
Load timing. A loose connection only shows its heat while current flows through it, so some areas have to wait for their busy period: a kitchen at service, a production line running, a hall at its working load (see what load a survey needs).
Recording. Each finding is logged with its location, the measured temperature, the difference in °C from a matching reference and the load at the time. That record is what makes the report usable later.

What makes it quicker

An asset list or single-line diagram sent before the day, so the route can be planned.
An electrician allocated to the survey for the whole visit.
Keys, permits and inductions arranged in advance (see how a live data centre should prepare).
The visit booked for when the site is busiest electrically, so nothing needs revisiting.

Data centres

A live data centre survey is usually longer per panel than an office. Access is escorted, each hall may need its own permit, and work has to fit around change freezes and maintenance windows. In a colocation site the operator and each customer may control different areas (see who arranges access in a colocation data centre). None of it needs a shutdown: switchgear, UPS, busbar, PDUs and cooling plant are imaged live.

Splitting a survey over several visits

Large sites and FM portfolios are often surveyed over several visits rather than one long one. That is fine, and often better, because each area can be caught at its working load. The quote should state the days on site and what each visit covers, so nobody is surprised (see what affects the cost of a survey).

When the report arrives

Ti Thermal Imaging issues the report the same day as the survey, so any urgent finding can be acted on straight away rather than waiting for the paperwork (see how quickly you should get the report). Ti inspects and reports; the site’s electrical contractor investigates findings with the circuit isolated and carries out any work.

Why the time is worth spending

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. Each one was found because a panel or joint was imaged at load, one after another. A rushed survey that skips boards or images them at the wrong time can miss exactly that.

Frequently asked questions

Does anything need to be switched off during the survey?

No. Thermography is non-contact and needs the installation running. Panels are opened live under the site’s own safe system of work.

Can the survey be done in one day?

Often, for a single building with a manageable number of boards and an electrician available all day. Larger sites are planned over several days, and the quote says how many.

Does a longer survey cost more?

Yes. Days on site are one of the main things that set the price, which is why good access planning saves money.