Trenchless cable exchange

Energy providers are increasingly confronted with the problem of exchanging defective underground cables with new ones. With the over-bore method TT has found a viable and economical solution for trenchless cable exchange employing the fluid-assisted Grundodrill HDD rig. The drill rods with the patented over-bore head are screwed together and driven over the old cable, parallel to its position. The old cable acts as a compulsory track. The wash-over head evenly cuts a small annulus around the old cable, separating it from the soil and any root growth holding on. On arrival at the target, the old cable is then very easily pulled out with a towing vehicle. The compulsory guide makes detection obsolete. However, additional inspection of the bore path is highly recommended. It allows immediate reaction to any deviation from the intended path.

When pulling back the drill rods, the new cable is pulled in simultaneously. After the wash-over head has successfully passed practical tests it is now offered to interested TT customers.

• Wash-over lengths between 100 and 150 metres
• Application so far: exchange of 10 kV and 20 kV power cables and telecom trunk cables, 40 mm in diameter and larger
• High installation speed - great time-saving (open-trench installation takes five times as long) - eco-friendly new installation
• With only one bore: the old cable is bored clear - the new cable is pulled in. pulling out the cable is done with a towing vehicle which is usually avaiable on site
• Complete removal of the old cable -  no remainings in the soil
• Unproblematic separation of the old cable from soil or clinging roots
• No need to locate a new bore path: you can bore in a free path. 
• No new measurement and cadastral registration, the old bore path is used for the new cable
• No time delay due to the application for a new right of way
• Soft cable bedding due to Bentonite coating - better heat conducting properties than sand
• Economical installation, particularly in greater depths, due to the dispensability of civil engineering works
• Installation of (punched) protection pipes for subsequent cable pulling as an option
  

Advantages for the executing company:

• · Economical acquisition of new application fields
• Utilisation of existing equipment with special wash-over heads (from TRACTO-TECHNIK only)
• Suitable for boring free any drill rods which are stuck in the soil
• Old cables as compulsory track – no detection required
• Trenchless replacement secures a competitive advantage
• No laborious jobsite preparations, quick execution, selective intervention, simple access to the work places, minimal machine and equipment stock required
• Trenchless exchange – advantage for tree preservation by-laws