Project profile: Improving switchgear inspections at London’s Stansted Airport

In this project profile, Lonsdon Stansted Airport Engineering Team performed an existing building retrofit in order to reduce the amount of time needed for maintenance inspections.

By Candy Mizer March 20, 2014

Project name: Improving Switchgear Inspections at London’s Stansted Airport

Project type: Existing building retrofit

Engineering Firm: London Stansted Airport Engineering Team

Building type: Utilities/public works/transportation

Location: Stansted, Essex, United Kingdom

Timeline: Nov. 11, 2012 – Dec. 24, 2012


Building details

London Stansted Airport has permission to handle 35 million passengers annually and currently 17.5 million people pass through the terminal building each year. The airports electrical structure is enormous. Power is brought onto the site at 33kV and transformed down to 11V. 

Project details

At best, Stansted’s engineers had four hours per night in which to conduct predictive maintenance inspections. By the time they had the system safe, the window of opportunity was reduced even more. This meant the entire inspection cycle was significantly protracted and no system could be checked under load. With the installation of IRISS CAP Series infrared inspection windows, the savings in terms of inspection time and associated costs went up dramatically. Payback was instant, but the benefits extended beyond that.

Project success

Once the IRISS windows were installed there was an immediate impact on switchgear inspections time. It took just took five hours to complete the job in daylight hours, including walking from one substation to the next and coffee breaks. Previously, it took the engineers two nights to inspect just one panel. There is no longer a need for isolations or back feed, and the engineers’ safety is completely assured. A single thermographer with a thermal imaging camera and without PPE can do everything. An initial thermal survey of the fully energized low-voltage systems that serve the main terminal block showed just two minor cable faults. For the first time, the airport had a benchmark for trending future performance and the complete assurance that everything was working optimally. This was not possible before install the IRISS CAP Series IR window.


London Stansted Airport, Enterprise House, Bassingbourn Road, Essex, United Kingdom CM24 1QW