Short answer: usually the site’s own authorised electrician, or the maintenance contractor’s, opens and closes the covers under the site’s permit to work. The thermographer does not touch the equipment. They image each connection once the cover is off, record the load, and move on. Agree who opens what, and when, before the survey day.
It is one of the first questions facilities and contract managers ask us, and it decides more about how the day goes than the camera does.
Why the thermographer doesn’t open the covers
Removing a cover from energised switchgear or a distribution board is work near live conductors, so it sits under the site’s own safe system of work: its permits, its risk assessments and its list of authorised people. The site’s electrician knows the installation, holds the keys and knows which panels can be opened live and which cannot. Ti inspects and reports. Keeping the two roles apart keeps the survey inside the site’s rules and lets the thermographer concentrate on the images.
What to arrange before the day
- An equipment list by building, room and panel, so both of you work from the same references.
- Who is authorised to open each type of equipment, and for how long they are available. On most surveys the electrician walks the whole route with the thermographer.
- Permits for switch rooms, plant rooms and restricted areas, issued before the start time rather than on arrival.
- Access equipment where it is needed. On one manufacturing site in October 2026, some of the 26 busbar feeds could only be reached from a cherry picker.
- A time when the load is normal. A connection only shows a problem when current flows through it, so the survey needs a working day, not a quiet one.
What happens on the day
The electrician removes a cover, the thermographer images the connections straight away from a safe distance, notes the load on the circuit and takes a matching digital photo, and the cover goes back on before the pair move to the next panel. Imaging promptly matters, because exposed parts start to cool once the cover is off. Anything that needs attention is explained on site, and the report usually follows the same or next working day.
When a cover can’t come off
Some equipment should not be opened live, and some sites do not allow it. In those cases the options are infrared windows or viewing panes fitted to the cover, imaging what can be seen safely from outside, or scheduling those items for a planned shutdown with a separate check. Whatever the reason, a good report lists every item that was not imaged and why, so nothing is quietly left out.
Who should do the imaging
A certified thermographer, Level 2 or above, working alongside your authorised electrician. Our thermographers are ITC Level 3 and Ti is a Level 3 certified company. We have carried out more than 700 electrical thermography inspections across a national distribution and logistics network since 2018, and the same planning questions come up on every one of them: who opens what, when, and under whose permit.
More on how live surveys run: data centre electrical thermography, switchgear thermography, annual PPM thermography, busbar thermography at commissioning and the 7 electrical risks that cause data centre downtime.
Frequently asked questions
Do we need an electrician for the whole survey?
Usually, yes, for the time on site. A clear equipment list and a planned route keep that time short. If you can’t provide one, tell us when you ask for a quote so we can plan around it.
Is it safe to open panels while they are live?
That is for the site’s risk assessment to decide, panel by panel. Where it isn’t safe or permitted, infrared windows let the equipment be imaged with the cover on.
Can the survey be done at night or at weekends?
Yes, as long as the equipment is carrying its normal load then. On many sites the quietest shift is the worst time to survey, and the report should record the load either way.
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 ITN.