The network upgrade going on underneath the M27 while thousands of vehicles pass by overhead
Scottish and Southern Electricity Networks’ (SSEN) £9.6 million investment in the distribution network at Rownhams in Hampshire is now well underway, with works going ahead without disruption to motorists, despite the new cable crossing beneath the busy M27 motorway.
SSEN’s team, working with contract partners Freedom, has carefully designed the scheme to deliver long-term benefits by upgrading the local electricity infrastructure, while keeping disruption to a minimum and protecting the surrounding environment.
Rather than installing new power cables over or through the motorway – which would have caused delays for motorists – the team has used a solution to route them well beneath the M27 instead.
By rethinking the original design and adopting a more complex underground approach through the use of a Horizontal Directional Drill (HDD), the project avoids unnecessary disruption to motorway traffic, while helping reduce the impact of construction activity on the local flora and fauna.
How the Horizontal Directional Drill works
The total length of the drill being used in the Rownhams project is some 260 metres. National Highways stipulates that the drilling must take place at least 15.8 metres beneath its carriageways. The nature of the area, and the location of the road, means that the actual drill depth reaches 45 metres down from where it was launched, to what's known as the reception pit. During drilling itself, a mixture of water and a non-toxic, naturally-occurring-clay is used to keep the drilled space clear, prevent collapse, and remove debris.
SSEN’s Project Manager, Tim Eccleston says: “This multi-million-pound investment is about future‑proofing the electricity network for local homes and businesses, while enabling the nearby Rownhams services to install more electric vehicle charging hubs. The location, at one the south’s busiest motorways, is critical in that it allows motorists to recharge their EVs at a key journey point. But this location also created the challenge for us to think about how we could carry out this upgrade without adding to roadworks and disruption on the motorway. Our commitment was to ensure this project could be designed in a way that works for customers, road users and the environment, and by changing the cable route to run beneath the M27, we’ve been able to deliver on that commitment.”
This £9.6m programme of works is ongoing and once complete will further strengthen electricity supplies for local customers, while supporting the provision of new EV charge hubs on a key section of the UK’s road network.
SSEN’s project demonstrates how critical electricity infrastructure can be delivered in a smarter, more considerate way while strengthening the network, supporting the transition to electric vehicles and keeping people moving on one of the south of England’s busiest motorways.
