High voltage cable installation and jointing work on the electricity distribution network carries extreme risks of electrocution, arc flash, and cable failure. HV cables operate at voltages of 11kV and above, where contact or proximity is instantly fatal. Only specifically trained and authorised persons may work on HV systems. This talk covers the critical safety controls for HV cable work on UK infrastructure projects.
Key Hazards
Fatal electrocution from contact with energised HV cables during jointing
Arc flash explosion causing severe burns during cable termination work
Backfeed from distributed generation energising cables believed to be dead
Cable drum injuries during handling of heavy cable reels and pulling operations
Control Measures
Ensure all HV cable operatives hold the specific authorisation issued by the network operator.
Isolate, earth, and prove dead all HV circuits before any jointing or termination work begins.
Apply personal earths at the immediate work location as a secondary protection measure.
Use only HV-rated insulated tools and test equipment certified for the system voltage.
Establish an exclusion zone around the jointing location to prevent unauthorised approach.
Follow the network operator's approved safe system of work for every HV cable operation.
Verify isolation with the control engineer and obtain a safety document before starting.
Brief the jointing team on the specific cable identification, isolation points, and earthing locations.
Record all isolation, earthing, and testing activities in the safety documentation.
Emergency / Rescue
If an arc flash or electric shock occurs on an HV system, do not approach. Isolate from the control room if possible. Call 999 stating high voltage electrical incident. Keep all persons at least 5 metres from the affected equipment until confirmed isolated and earthed.
Remember
Only specifically authorised persons may work on high voltage cable systems
Isolate, earth, and prove dead at the work location before touching any HV cable
Apply personal earths at the immediate work position as secondary protection
Follow the network operator's approved safe system of work for every operation
Verify isolation with the control engineer and obtain a safety document before starting
Applicable Legislation: Electricity at Work Regulations 1989 · HSG85 (Electricity at Work: Safe Working Practices) · Distribution Safety Rules · CDM 2015