Yes. On a multi-let industrial or self-storage estate, the landlord usually owns the supply as far as each unit’s incoming isolator: the intake, the estate main switchboard, feeder pillars and the cables to each unit, plus estate lighting, gates and pumps. All of it can be surveyed live, with nothing switched off. Survey on a working weekday, when the units are trading and drawing real load.
Why estate supplies get missed
Each tenant looks after the boards inside its own unit. The landlord’s managing agent looks after the roads, roofs and lighting. The equipment in between, the intake and the pillars feeding every unit, can sit outside both plans. One poor connection in a feeder pillar can take out several units at once, so it belongs in the landlord’s survey (see tenant boards in a landlord’s survey).
What should be in scope
- The intake and estate main switchboard, including incoming terminations and outgoing ways.
- Feeder pillars and distribution cabinets that supply the units, opened by the site’s authorised person.
- Landlord’s meter and isolator positions up to the agreed boundary with each tenant.
- Estate services: external lighting boards, gate and barrier controls, CCTV supplies, and any surface water or foul pump panels (see outdoor equipment in UK weather).
- Self-storage sites: lift motor rooms, door and access control panels, and the main distribution for the storage blocks.
When to survey
A connection only shows a problem while current flows through it (see what load a survey needs). Pick a working weekday, mid-morning to mid-afternoon, when workshops, trade counters and light industrial processes are running. Estate lighting is imaged after dusk, or on its test setting, so it is carrying current.
Vacant units draw little or nothing, so the ways feeding them show little. If a circuit is lightly loaded at the time, the report says so and the reading is treated as indicative.
Access and outdoor equipment
- Weather: wind cools surfaces and sun heats them. External pillars are imaged out of direct sun where possible, with the readings taken from inside the opened enclosure, not off the door.
- Tenants: where the boundary is inside a unit, the agent arranges access with the tenant in advance.
- Keys and permits: pillars are often locked with different keys. Gather them before the day.
What the report gives you
A same-day report from Ti Thermal Imaging that locates each finding by pillar, way and phase, with the measured temperature, where it was taken, the difference in °C from a matching reference and the load at the time. Anything that could not be imaged, because it was locked, vacant or unloaded, is listed so the gap is visible. Ti inspects and reports; the landlord’s electrical contractor investigates findings with the circuit isolated and carries out any work.
What installation-stage thermography can find
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. An industrial estate is simpler, but the principle carries over: check the connections that many users depend on, while they carry real load.
Frequently asked questions
Who should pay for the survey?
Usually the landlord, through the service charge, for the landlord’s equipment. Tenants survey their own boards.
Do units lose power during the survey?
No. The survey is done live; nothing is switched off.
Does this replace the EICR?
No. They answer different questions (see thermography vs EICR).
Related reading
- Surveys for due diligence when buying or leasing
- Data centre electrical thermography
- Switchgear thermography
- Annual PPM electrical thermography
- 7 electrical risks thermography finds
Ti Thermal Imaging’s surveys are carried out by ITC Level 3 thermographers, and Ti is a Level 3 certified company. Our work has featured on BBC News and ITV.
Talk to us: +44 20 3885 7464 · sales@thermalimaging.co.uk · contact page
About the author: Rachael Browning, General Manager, Ti Thermal Imaging.