We are seeking an experienced and motivated Site Supervisor with SF6 experience to oversee works across National Grid sites nationwide. This role is ideal for a hands-on supervisor with a strong background in high-voltage substations, gas-insulated switchgear (GIS), and safe handling of SF6 gas. The successful candidate must be willing to travel extensively and work on projects throughout the UK. You will be responsible for supervising site teams, ensuring works are completed safely, on time, and to the required quality standards while maintaining full compliance with National Grid procedures and regulations. Key Responsibilities * Supervise daily site activities across National Grid transmission and substation sites. * Lead and coordinate operatives, subcontractors, and specialist engineers on site. * Oversee installation, maintenance, testing, and decommissioning works involving SF6-insulated equipment. * Ensure all SF6 gas handling, recovery, leak testing, topping-up, and disposal is carried out in line with environmental and safety regulations. * Conduct site briefings, toolbox talks, and ensure RAMS are followed at all times. * Maintain excellent health & safety standards and enforce safe systems of work. * Liaise with National Grid representatives, project managers, and clients. * Manage site documentation including permits, progress reports, timesheets, and inspection records. * Monitor progr...