Cable Strikes | 10kV Medium Voltage (MV) Cable Struck By An Excavator

Published 18 May 2021

USAG

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 Strikes | How To Support LV to 33kV Electricity Cables

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Incident Overview

Incident Type: 10kV Electrical Strike

Project/Location: McDonalds Restaurant, Mullingar, Co. Westmeath

Client: Gas Networks Ireland

Incident Date: 24-03-2019

Summary

During planned weekend work a 10kV medium voltage (MV) cable was struck by an excavator. A subcontractor/DLO blended team were tasked with extending the existing gas main at a depth of approximately 1.7m.

Temporary works designs were authorised and planned for the job. Service plans were provided in the job pack and indicated the presence of a 10kV/20kV MV cable. Cable was traced, located and marked. Despite knowing the presence of existing services, the team allowed the excavator to work within 500mm of the various utilities.

The cable was struck by a combination of the bucket of the excavator and material shift towards the ESB cable at a depth of approximately 400mm.

10kV Electrical Strike

Action Taken
  • Work stopped and ESB were contacted.
  • ESB came on site to complete ‘make safe’ temporary repairs and then completed full repair.
Lessons Learnt
  • Breach of the Code of Practice as plant was operating within 500mm of known or suspected services.
  • No protection placed over the pipe once exposed which could have provided visual and physical control.
  • Safe hand digging practices including use of the soil pick were not used in this location.
  • Marking of utilities was completed but has room for improvement (see photo above).
Follow Up Action Required
  • Significant Incident Review to be held week ending 07.06.19 with relevant personnel involved, PE Operations Manager, HSEQ Manager and Head of Contract. Just Culture model.
  • This Lessons Learned document to be cascaded to all relevant operational personnel with briefing register signed as read and understood by all.
  • All contracts should ensure that all employees have undertaken an operationally lead, Making Safety Personal (MSP) 1 session.
Action Holders Emmet O’Brien, Roisin Kelly & Neil Doherty – BBCLG, ALL SBU Heads of Contract & Operational Management, ALL SBU Heads of Contract & Operational Management

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

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.

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