Cable Jointing · Hertford, Hertfordshire

Emergency 11kV Cable Joint — Storm Damage Response, Hertford

An 11kV joint built and tested in the dark and the wet, to get a Hertfordshire village back on supply after a storm-felled tree took out the overhead.

LocationHertford, Hertfordshire
DateDecember 2024
Voltage11kV
ScaleSingle emergency joint
ClientDNO

Storm Bert tore through Hertfordshire in late November 2024, with one casualty being an 11kV overhead line on the edge of a village outside Hertford. A fallen tree took out a pole and snapped the cable. The DNO's local jointing capacity was tied up across the patch, and they called us in for an emergency joint.

On site by 17:30. Joint completed and energised by 22:10. Around 240 properties back on supply the same night.

What the job involved

  • Site safety setup and exclusion zone in wet, dark conditions with a halogen flood rig.
  • Cable end preparation on a sodden, slumped 11kV XLPE cable with damaged outer.
  • Cold-shrink straight joint built inside a temporary canopy tent.
  • Insulation resistance test before re-energisation under DNO authorisation.
  • Joint photo log and report issued to the DNO control room within 30 minutes of completion.

Key challenges

  • Standing water in the jointing pit — pump set up and ducting dammed.
  • Outer cable damage extended further than visible from initial inspection — cleanup added an hour.
  • Temperature dropped to 2°C overnight — heat shrink curing time monitored against ambient.

Outcome

  • Joint passed insulation test on the first attempt.
  • 240+ properties restored same evening rather than waiting until Monday.
  • DNO added us to their priority emergency call-out list for the following winter.

I called them at half four on a Friday in the middle of a storm. They were on site in under an hour with the right kit and a jointer who knew exactly what they were doing.

— DNO Emergency Coordinator, Hertford, Hertfordshire

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