Cable Strikes | HV Cable Joint Explosion

Published 18 May 2021

Cable Strikes

Utility Strike Avoidance Group

USAG have published a range of documents to assist industry understanding of the root cause and contributory factors behind specific incidents. The aim is to improve industry standards and reduce the number of cable strikes.

Cable damage is often caused by excavating machines – hand held tools such as pneumatic drills, crowbars, pins, picks and forks also expose workers to potential sources of danger when digging around underground cables.

Cable Hangers | Cable Ducting | Cable Protection | Electrical Safety Equipment

Incident Overview

What Happened?

A trial hole was excavated at a site in Wisbech, it was left open whilst other works on the site continued. Late in the evening an old clay cable joint surrounding an exposed steel wire armoured high voltage cable (11kV) exploded. The explosion set fire to roadside barriers that were lying over the hand excavated trial hole.

On the days prior to the joint failing it had rained but the excavation had not filled with water. The condition of the exposed cable and joint was believed to be in good condition when initially exposed.

The Fire Service and Police arrived on site, extinguished the fire and made the area safe. The loss of power affected approximately 1600 properties; thankfully no-one was injured.

What Do You Need To Do?

• Whenever you uncover a low or high voltage clay joint, or any type of cable joint which appears to be damaged or in poor condition, contact the local utility owner to inspect the joint before work continues in the immediate vicinity.
• Always support cables and joints in excavations appropriately, they must be suitable supported to prevent sag and strain on the joint.
• Never use other utilities to access and egress to and from excavations.
• Where possible use pumps to avoid excavations filling with water and submerging joints.
• Use appropriate security measures to keep members of the public safe.

Protecting Cables Against Strikes & Restoring Power Post-Strike

Thorne & Derrick have been distributors for 3M Electrical since 1985 and can provide a range of reliable and easy to install Cable Repair Products – this includes Scotch Tapes, Scotchcast Joints and Cold Shrink Tubes to provide effective re-instatement of cable sheath jackets on all types of LV MV HV cables in onshore and offshore locations with safe or hazardous area workplace classifications.

Cable Repair Products

Our range of cable protection covers manufactured by Centriforce provide underground utility protection of LV MV HV cables including Tapetile (11kV) and Stokbord (33kV 66kV 132kV) – contact us to discuss Cable Damage Prevention Products including Dectamesh, the underground detectable warning tape for alerting excavators of the presence of buried cables and to prevent potentially lethal accidents during excavation.

Stokbord

Tapetile