Principal Contractor’s Mechanical Commissioning Engineer - Outside of IR35 Contract Duration: 12 Months Overview: We are seeking an experienced Mechanical Commissioning Engineer to join the principal contractor’s team on a major gas generation project currently in the construction phase. The engines are already on site, and commissioning activities are ramping up. This is a site-based role suited to a hands-on engineer with a strong background in mechanical systems and commissioning. Key Responsibilities: * Lead and support mechanical commissioning activities for reciprocating engines, pumps, ventilation systems, and exhausts. * Collaborate closely with the construction and commissioning teams to ensure systems are installed and commissioned to specification. * Develop and execute commissioning plans, procedures, and documentation. * Interface with OEMs and subcontractors to coordinate commissioning schedules and resolve technical issues. * Ensure compliance with health, safety, and environmental standards throughout commissioning activities. * Provide technical input and troubleshooting during commissioning and early operations. * Support handover and performance testing phases. Requirements: * Proven experience in mechanical commissioning on large-scale energy or industrial projects. * Strong knowledge of reciprocating engines, pumps, ventilation systems, and exhausts. * Experience working for or with principal contractors in a site-based role. * Ability to read and interpret mechanical drawings and commissioning documentation. * Excellent communication and coordination skills. * Relevant engineering qualifications (HNC/HND/Degree or equivalent). * CSCS or equivalent site safety certification preferred