Overground vs Underground Cables

In England and Wales, distribution network operators (DNOs) manage the poles, pylons, and cables in local areas. These DNOs are responsible for ensuring that electricity is effectively distributed from the high-voltage transmission system to homes and businesses. There are currently around 500,000 miles of distribution lines in England and Wales. Recently, calls for more underground cable networks have increased, especially with the construction of new onshore windfarms and solar farms requiring new distribution infrastructure to connect to the national grid.

The government has stated that overhead lines will remain the standard for electricity distribution in the foreseeable future. Only in nationally designated landscapes like areas of outstanding natural beauty (AONB) and national parks, where overhead lines have a strong visual impact, are underground lines to be considered during planning.

Why Don’t We Install More Underground Cables?

While underground lines have a minimal visual impact on the landscape after installation, the engineering works required to bury the cables are extensive and can cause great damage to the landscape. The National Grid lists a number of issues that make underground lines more complicated and expensive than overground lines including the cost of construction, cost of the cable itself due to the different insulation required, and the risk of disturbing sensitive habitats or archaeological sites. Other issues can arise with maintenance and repairs. Although monitoring equipment is buried with the cables, when a fault arises, an underground cable is out of service for about 25 times as long as an overground cable.

Is Overhead the Solution?

OHL and Bird in field - image by Wirestock - Freepik The lower engineering costs for the installation of overhead distribution lines and reduced downtime during repairs are strong arguments for this technology. Although overhead lines are more at risk of damage during storms or wildfires, the damage is easily detected and quickly repaired. Overhead lines are more easily rerouted or modified to serve customers, keeping disruption of the power supply to homes and businesses to a minimum.

The visual impact of power utility poles can be problematic in some areas, but there are ways to make them blend better into the landscape. One effective option is using wood, the most traditional material for utility poles. Wood is a renewable resource and easy to install. Modern protection technologies, such as the Polesaver sleeve, help maintain the stability and security of wood poles by preventing rot at the ground line. Additionally, Polesaver sleeves offer protection against termites and wildfires, ensuring the durability of wood poles throughout their lifespan.

Looking to the Future

The government is planning to modernise and strengthen the national grid as part of its work towards net-zero, including faster construction of new distribution infrastructure and cutting the time it takes to connect viable projects to the grid. At the moment, overhead cabling seems to be the best way to support these plans. The balance between overhead and underground cables will continue to be a topic of discussion as we strive for an efficient and sustainable electricity distribution network.

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Polesaver is the leading manufacturer of products designed to increase the life of wooden utility poles for 20 years. Get in touch for further information, or to arrange a TEAMS call to discuss our products.

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