When should a theatre or cinema have its electrical thermography survey?

Survey when the building is working hardest: during a performance or a full technical rehearsal with the lighting rig lit, the sound system on and the auditorium plant running. Back-of-house switchrooms, dimmer rooms and plant can be imaged while the show runs, with nothing switched off. A dark day gives a quiet building and a weak result.

Why a dark day is the wrong day

A poor connection shows by the heat it gives off while current flows through it (see what load a survey needs). In a theatre or cinema, the heaviest loads sit around show times:

Stage lighting and dimmer racks carry real current only with the rig lit.
Auditorium heating, cooling and ventilation work hardest with a full house.
Projection, sound and bars are all running in the hour before and during the performance.

On a dark day or a quiet weekday morning, much of this sits idle. That is the easy day to visit, and the day the survey shows least.

Two ways to plan it

During a performance: the thermographer works back of house, in switchrooms, dimmer rooms, plant rooms and the projection area, while the show runs. Front-of-house areas are left alone once the audience is in.

During a technical rehearsal or get-in: with the rig lit and the sound system on, the stage electrics can be imaged with more room to work. Ask the production electrician which states use the most of the rig.

What should be in scope

Intake and main switchboard, and sub-mains to stage, auditorium, front of house and plant.
Stage power: dimmer racks, stage distribution and temporary power points used for touring shows.
Projection and sound supplies in cinemas and auditoria.
Auditorium HVAC control panels and their supplies.
Bars, kitchens and kiosks, surveyed in the interval rush or before the doors open.

Traps a good thermographer avoids

Dimmers and some power electronics run warm by design, so the report compares like with like: one dimmer channel with a matching channel at a similar level, giving the difference in °C. Lamps, lanterns and cooking equipment give off heat as part of their job and are not mistaken for a connection problem. Every reading says exactly where it was taken.

Working around the show

The camera is silent and nothing is isolated, so the performance is not affected. Panels are opened by the venue’s electrician or stage electrics team under the venue’s own safe system of work (see who opens the panels). Agree the route, timings and quiet areas with the technical manager before the day.

What the venue gets

A report that locates every finding by board, circuit and phase, with the measured temperature, where it was taken, the difference from a matching reference and the load at the time. Ti Thermal Imaging issues it the same day. Ti inspects and reports; the venue’s electrical contractor investigates findings with the circuit isolated and carries out any work.

Why load matters

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. They showed because current was flowing. A switched-off rig can’t show you the same thing.

Frequently asked questions

Will the audience notice?

No. The thermographer works back of house and stays out of the auditorium during the show.

Can touring company equipment be surveyed?

The venue’s own installation and its power points can. A touring company’s own equipment is theirs to arrange.

Does it replace the EICR?

No. Thermography finds heat at connections under load; an EICR tests the installation (see does a thermographic survey replace an EICR?).