The Strategic Road Network has a 40+ year legacy of uncharted, unmarked and unducted cabling congesting its boundaries.

Verges and central reservations host a risk ridden, spaghetti-like jumble of direct buried cable. This underground network of cable has the potential to be struck every time ground is broken, leaving contractors and operatives with many safety unknowns and, more importantly, safety risks each and every time they carry out their work.

To make problems even more complex, new cable is often laid over old, amplifying the already difficult challenge – as redundant cable is left in the ground long after the assets it once powered have been removed or replaced.

There is a risk of cable strike every time ground is broken, and some of the contributing factors to that risk include:

• Cables historically being direct buried, often with no sand or marker tape and rarely ducted.
• Cable is rarely laid in straight lines, often taking the path of least resistance to enable speed of trenching and laying.
• Redundant cable has not been removed when assets have been removed or replaced.
• Assets which are not turned on are more difficult to locate and identify.
• Even where cable is charted, exposing a cable necessitates some action to identify and move, remove or redesign of the works.

The impact of this congestion means that any scheme breaking ground is at risk of:

• Standing time and delay
• Abortive Traffic Management
• Increased costs
• Service Strike causing loss of power to assets, properties or infrastructure and personal injury.

Solution #1: Ground Penetrating Radar (GPR)

Crown Highways provides its GPR service to clients, replacing the traditional method of Cat & Genny service location.

Ground-penetrating radar (GPR) is a non-invasive geophysical survey method that can be used to ‘see’ objects buried underground, before ground is broken.

Using electromagnetic energy, an antenna is passed along the ground surface and registers signals as they bounce off buried objects or cavities. This provides a further rubber stamp of safety from Crown Highways, with the ability to identify an object beneath the surface before an excavation commences – further reducing the opportunity for cable strikes.

The solution also enables Crown to make the best decision as to the safest method of operations when excavation does commence.

Solution #2: Vacuum Excavation

In collaboration with Suction Excavation UK, Crown Highways provide a Vacuum Excavation service.

The safest method of breaking ground, instead of using machinery to haul out soil, a high-powered suction system is instead employed to remove all unwanted materials, both solid and liquid, from the excavation

This delivers the following benefits:

• Reduced associated health and safety risks, such as cable strikes
• Cleaner and tidier, the equipment not only removes the debris but stores it as well.
• The method is faster compared to traditional digging itself which makes it more cost effective over a project.

Solution #3: Intrusive Testing

Using its years of experience and expertise, Crown Highways provide a solution which can be programmed into the delivery of any works to minimise the impact of finding unknown cable.

Crown Highways offer a bespoke Intrusive Testing service to:

• Assess and test exposed cables to ascertain if they are live or have the potential to be live.
• Trace cable to source and identify.

Crown’s trained and competent Live Jointing Engineers are able to work safely on live cable and are available to attend site and complete their work with minimal impact to a programme. As an extension to this service, the Crown Highways team is able to propose solutions to move, mark and chart the cable or remove redundant cables entirely for the betterment of the network.

Whether making existing cables dormant, removing cables altogether, re-routing or temporary switch off, the Crown Highways team has the knowhow to make the right choice for each individual scheme and site. In an industry where safety is absolutely paramount, Crown Highways steps in and removes unnecessary risk when it comes to cable strikes with this bespoke solution.

Mike Dale, Crown Highways MD commented:

“On site, safety is priority number one and when it comes to cable detection and effective management of existing cabling, GPR, vacuum excavation & intrusive testing should be non-negotiable on-site as far as we’re concerned. We work in an industry that comes with risk and safety threats – and we mitigate those the best we can, as often as we can. Some variables still can’t be fully controlled, however, but there is no excuse for a sub-par protocol when it comes to potentially dangerous cable strikes considering that there are safety boosting methods available.”