HV Switching & Authorised Personnel Services
Qualified Authorised Persons for high-voltage switching operations, load transfers, and emergency isolations.
High-Voltage Switching Operations
High-voltage electrical systems require specialist knowledge, formal authorisation, and strict safety procedures. Our Authorised Persons (APs) are trained, qualified, and approved to carry out switching operations on HV systems up to 33kV, ensuring safe isolation, load transfers, and maintenance access.
Incorrect HV switching can result in catastrophic equipment failure, arc flash incidents, and life-threatening injuries. We operate under strict Permit to Work (PTW) systems, isolation verification procedures, and risk assessments for every operation.
HV System Categories We Manage
11kV Switchgear
Most common UK commercial voltage. Ring main units, transformers, and distribution panels requiring qualified APs for all switching operations.
6.6kV & 3.3kV Systems
Industrial sites, manufacturing plants, and older estates. Step-down transformers feeding LV distribution boards.
33kV Infrastructure
Large campuses, data centres, and utility connections. Requires additional safety measures and authorisation levels.
Generator HV Changeover
Switching between mains supply and backup generators, including synchronisation and load transfer procedures.
Switching Operations We Perform
Planned Maintenance Access
Isolation of HV equipment to allow safe access for transformer servicing, circuit breaker maintenance, or protection relay testing. Full PTW procedures and earthing applied.
Load Transfer Operations
Transferring electrical loads between transformers, ring main sections, or backup systems. Critical for minimising downtime during planned works or equipment replacement.
Emergency Isolations
24/7 response for fault conditions, equipment failures, or fire alarm activations requiring immediate HV isolation. Rapid deployment of authorised engineers with full PPE and switching documentation.
Generator Synchronisation
Connecting backup generators to the HV network under controlled conditions. Includes frequency matching, phase alignment, and gradual load pickup to prevent system shock.
Cable Jointing Access
Providing dead isolation for HV cable jointing, termination work, or underground cable fault repair. Includes cable identification, phasing checks, and post-work energisation.
Authorised Person (AP) Requirements
Formal Qualification: City & Guilds Level 3 in HV Switching or equivalent, demonstrating technical competence in electrical principles, system design, and safety procedures.
Site-Specific Authorisation: Written approval from the site Duty Holder confirming the AP's competence to work on specific HV equipment under defined conditions.
Arc Flash Training: Understanding of arc flash hazards, PPE requirements, approach distances, and emergency response procedures for high-energy fault conditions.
Medical Fitness: Current medical certificate confirming fitness to work on high-voltage systems, including vision, reaction time, and cardiovascular health assessments.
Competency Refreshers: Annual revalidation training to maintain authorisation, covering system changes, incident learnings, and regulatory updates.
Risk Management & Safety Protocols
Every HV switching operation follows a strict risk assessment and method statement (RAMS) process. We identify potential hazards, control measures, and emergency procedures before any work begins.
Key controls include: isolation verification using approved voltage indicators, mechanical interlocking to prevent incorrect switching sequences, segregated earthing to protect against induced voltages, and clear communication protocols between the AP and site management.
Our APs carry full arc flash PPE including face shields, flame-resistant clothing, and insulated tools. All operations are logged, with switching diagrams, isolation certificates, and incident records maintained for audit and insurance compliance.
Related Services
Arc Flash Risk Assessment
Quantify electrical hazards and establish safe working procedures for HV and LV systems.
Generator Maintenance
Backup power servicing including transfer switch testing and load synchronisation.
Electrical Compliance
Complete electrical testing, inspection, and certification across all voltage levels.
UPS Maintenance
Uninterruptible power supply servicing to maintain critical load protection.
PPM Delivery
Planned preventive maintenance programs integrating HV switching schedules.
Thermal Imaging
Infrared surveys to detect HV equipment faults before failure occurs.
Frequently Asked Questions
Need HV Switching Support?
Authorised Persons available 24/7 for planned maintenance, emergency isolations, and load transfers.