How to prepare your electrical installation for a thermographic survey

A thermographic survey uses a thermal imaging camera to find electrical hot spots — loose connections, overloaded circuits, failing components — before they cause a fault or a fire. It’s non-invasive and it’s often requested by insurers as part of planned maintenance. But the quality of a survey depends heavily on the conditions on the day, and a little preparation makes a real difference.

Here’s how to get the most out of one.

It must be under normal load — don’t switch things off

This is the single most important point, and the one people most often get wrong. Thermography works by detecting heat, and heat is generated by current flowing under load. A circuit that’s been switched off, or a building that’s shut down for the visit, hides exactly the faults the survey is meant to find.

So the survey should happen while the installation is running as it normally does — ideally when it’s reasonably busy, not first thing on a quiet morning. Counter-intuitively, “tidying up” by turning equipment off before the surveyor arrives is the opposite of helpful.

Make sure the boards and panels are accessible

The surveyor needs to get to the distribution boards, panels, switchgear and any equipment that’s part of the scope. Before the visit:

• Clear storage, stock or furniture away from electrical panels and cupboards
• Make sure keys are available for locked intake rooms, risers and plant rooms
• Confirm who on site can grant access to each area
• Flag anything in a restricted, hazardous or awkward-to-reach location

Every panel that can’t be reached is a panel that can’t be surveyed — and that has to be recorded as a limitation.

Removing covers safely

To image the connections inside a board, dead fronts or covers usually need to come off while the installation is live. That’s skilled, potentially hazardous work, so it must be done by a competent person working safely — either our engineer or a suitably qualified person on your side, agreed in advance. Sorting this out before the visit avoids wasted time and keeps everyone safe.

Have your records to hand

The survey is far more useful when it can be tied to the installation’s documentation. If you have them, make available:

• Single-line diagrams or schematic drawings
• Circuit schedules and board labelling
• Any previous thermographic or EICR reports
• Notes on known issues or circuits that have given trouble

This lets findings be pinpointed to specific circuits rather than described as “the third board on the left.”

Pick sensible timing

Because the installation needs to be under load, coordinate the visit with your normal operating pattern rather than a shutdown. If certain processes only run at particular times, tell us — we can plan the route so the important equipment is imaged while it’s actually working.

What you get at the end

A good survey produces a clear, dated report with thermal and normal images, the findings and their severity, and the recommended action — separated so urgent items stand out from routine ones. It’s the kind of evidence that’s suitable for submission to your insurer or facilities team, and a sensible part of ongoing commercial electrical compliance.

If you’ve got a survey due — for your insurer or just to get ahead of a fault — tell us about the premises and we’ll arrange a visit that fits around your day.