By Andy Hirst

A Huddersfield company’s invention has prevented more than 100 explosions beneath pavements across UK’s major towns and cities which could have maimed or even killed people.

Associated Utility Supplies Ltd based at Clayton West devised a blanket to smother explosions in electricity boxes beneath pavements in the country’s most densely populated cities.

They devised the link box protection blanket after dozens of these electricity boxes exploded, injuring people, setting fire to cars and damaging buildings.

The problem became so bad, especially in London which saw 40 explosions in 2014, that the Health and Safety Executive put pressure on the six regional electricity distribution network operators to do something about it, so they turned to AUS for help as it has an excellent reputation for innovation within the industry.

The blanket is now in every link box in London plus tens of thousands more across the country and has been known to prevent at least 100 explosions after boxes became faulty.

When this happens it causes what’s known as an arc flash – basically a flashover explosion – that could potentially kill or maim a passer-by and cause serious damage to properties and vehicles. The heavy cast iron link box pavement cover has been known to be hurled up to 40ft by the force of some blasts which also generate fire and an incredible amount of heat.

It’s often difficult to pinpoint a cause for link box explosions, but it’s thought that vast changes in temperature from heat in summer to cold in winter can loosen bolts on the many transformers within the box, causing a short circuit. Water getting into the link box can also spark an arc.

A link box blanket being installed in a link box

AUS product development and innovation manager Harvey Kangley (main image) said: “It was a major health and safety issue for all the electricity distribution companies as no-one could know when these boxes would blow. There’s just no warning at all.

“The Health and Safety Executive was really worried about the danger so we knew we had to act quickly with our research and development to find something that could mitigate the explosions.

“The thing is these link boxes are everywhere but covered by iron lids set into pavements so no-one even knows they are there. With hundreds, if not thousands, of people walking over some of them every day in places like Oxford Street and Covent Garden it was clear something had to be done to mitigate the danger.”

The company has devised 24 variants of the blanket to fit all sizes of link boxes along with specialist tools to fit them snugly and also a device to stop the bolts from loosening.

The blanket invention is so specialised the company had to go to a laboratory in Budapest, Hungary, to test the prototypes against arc flashes.

The industry had turned to AUS because it had previously devised a cable damage blanket to cover damaged live cables to protect the public while engineers were carrying out repairs and the company is well-known for its innovation in both the electricity and railway industries.

It means that the UK’s six distribution network operators – Scottish and Southern Electricity Networks, SP Energy Networks, Electricity North West, Northern Powergrid, UK Power Networks and Western Power Distribution – now all have at least some of the blankets.

UK Power Networks covers London and has now installed the blankets in every link box in the capital.

Northern Powergrid, which covers Yorkshire, the North East and north Lincolnshire, has an ongoing programme and commitment to install a blanket in every one of their estimated 40,000 link boxes.

There are now well over 167,000 blankets protecting link boxes nationwide in cities such as London, Liverpool and Manchester and the programme continues to be rolled out.

* Written by former Huddersfield Examiner Head of Content ANDY HIRST who runs his own Yorkshire freelance journalism agency AH! PR ( specialising in press releases, blogging and copywriting.