Offshore Inspection Guide Electrical Power Systems

Energy Division Offshore Inspection Guide Electrical Power Systems Open Government Status

Fully Open

Publication Date 31 March 2026

Review Date 31 March 2029

Review History

Version Date Changes Approved 1 Final published April 2026 First issue

Target Audience

ED Offshore Inspectors / ED Specialist Inspectors Whilst primarily aimed at HSE EC&I inspectors, this guide will be useful to Duty Holders in managing risk in relation to major accident hazards and preparing for OMAR inspections.

Contents

Summary.......................................................................................................................................... 3 Introduction ...................................................................................................................................... 3 Relevant Legislation ......................................................................................................................... 4 Relevant HSE Guidance .................................................................................................................. 6 Action ............................................................................................................................................... 6 Background ...................................................................................................................................... 6 Other relevant Inspection Guides..................................................................................................... 7 Specialist Advice .............................................................................................................................. 7 Organisation..................................................................................................................................... 7 Targeting ...................................................................................................................................... 7 Timing........................................................................................................................................... 8 Recording & Reporting ................................................................................................................. 8 Appendix 1 - Electrical Power Systems Pre-inspection information request .................................... 9 Appendix 2 - Power Generation and Distribution ........................................................................... 10 Appendix 3 - Power Quality and Analysis ...................................................................................... 12 Appendix 4 - Control and Protection .............................................................................................. 14 Appendix 5 - Temporary and Portable Systems............................................................................. 16 Appendix 6 - Safety and Compliance ............................................................................................. 18 Appendix 7 - Acts / Regulations / Benchmark Standards ............................................................... 22 Appendix 8 - Application of the Enforcement Management Model (EMM) and Duty holder Performance Assessment........................................................................................................ 25

Summary This Inspection Guide outlines an approach to the inspection of duty holder’s arrangements with respect to Electrical Power Systems and the key areas that inspectors should consider when inspecting this topic. It also sets out the criteria for satisfactory and unsatisfactory performance factors against which duty holder performance will be rated. References are made to technical standards and guidance that inspectors will use to form an opinion of legal compliance.

Introduction The aim of this Inspection Guide is to provide information and guidance to ED Inspectors to support the delivery of consistent and effective inspection of duty holder arrangements to comply with the Offshore Installations (Offshore Safety Directive) (Safety Case etc) Regulations 2015, Safety Case Material Changes, Combined Operations Notifications, Safety Case Thorough Reviews, Safety and Environmental Critical Elements, Performance Standards and other relevant legislation and guidance.

This Inspection Guide outlines the key areas to be assessed and provides a framework for inspectors to judge compliance, rate performance, and determine appropriate enforcement action where legislative breaches occur. It supports HSE’s Enforcement Policy Statement (EPS) and Enforcement Management Model (EMM), ensuring electrical safety both for major accident prevention and personal protection is embedded in regulatory decisions.

Inspection of electrical power systems focuses on:

Major Accident Hazard Controls • Preventing the initiation of fires, explosions or loss-of-containment events arising from electrical equipment, faults or unsafe energisation, consistent with Electricity at Work Regulations (EAWR) requirement to prevent danger from electrical systems. • Ensuring electrical systems are designed, installed, operated and maintained so they remain suitable, safe, and reliable, consistent with EAWR requirements for safe construction, adequate protection, and proper maintenance. • Verifying that electrical systems are maintained in a safe condition through appropriate inspection, testing and defect management so that reliability is ensured and major accident hazards are effectively controlled. • Confirming that systems remain adequately protected against overload, fault current, atmospheric conditions and deterioration.

Electrical Personal Safety Consistent with EAWR duties to prevent danger, electrical safety measures must also protect personnel from: • electric shock and electrocution • arc flash and arc blast hazards, including thermal, pressure and projectiles • burns and fire resulting from electrical faults

• inadvertent energisation due to inadequate isolation, testing, or lock-off practices • failures related to competence, supervision or use of unsuitable tools, test equipment or PPE

Effective inspection therefore considers: • the adequacy of safe systems of work for electrical tasks, including isolation, proving dead, and permit-to-work controls • the competence of persons working on or near electrical systems, as required by EAWR • whether employers have taken all reasonably practicable measures to prevent electrical danger to individuals and to prevent electrical systems from contributing to major accidents

Effective inspection considers both the role of electrical systems in preventing major accidents and the measures in place to protect individuals from everyday electrical hazards.

This operational guidance outlines HSE’s current Electrical Power Systems intervention practices undertaken during onshore and offshore inspection. The topic breaks down into six core areas, detailed in the following appendices:

1. Power generation and distribution 2. Power Quality and Analysis 3. Control and Protection 4. Temporary and Portable Systems 5. Safety and Compliance 6. Documentation and records Equipment, Safety Notices and Personal Protective Equipment (PPE)

NB - It should be noted that the Electrical Power Systems guide excludes ATEX equipment, as this topic is considered a separate subject in its own right and will be covered under a distinct inspection guide.

Relevant Legislation There is a comprehensive range of guidance documents available from professional institutions and trade associations which can be helpful to duty holder’s in meeting the benchmark standards in this inspection guide. This inspection guide does not list these guidance documents specifically as there are many such documents from different organisations, often addressing the same subject-matter.

Not all of the benchmark standards contained in the guide are necessarily applicable at every platform. The duty holder should already be aware of the hazards and risks on their installation and hence which benchmark standards are applicable.

• Health and Safety At Work etc. Act 1974 (Application outside Great Britain) Order 2013 (AOGBO) applies the Health and Safety at Work etc. Act (HSWA) to offshore installations and any activity in connection with an offshore installation, or any activity which is immediately preparatory thereto from a vessel or in any other manner, other than towing the installation (see MAR Reg 4)

• Offshore Installations (Offshore Safety Directive) (Safety Case etc) Regulations 2015

• Management of Health and Safety at Work Regulations 1999 focusses on risk assessments and how to use them effectively to identify potential hazards and risks, preventive measures that can be applied and the management and surveillance of health and safety and procedures that should be followed in the event of serious or imminent danger.

o Regulation 3 - The regulation requires you to ensure that you make a suitable and sufficient assessment of the risks to the health and safety of employees and personnel not in your employment, for the purpose of identifying the measures you need to take to comply with relevant statutory provisions. In particular the Electricity at Work Regulations 1989, Regulation 4 (3), whereby every work activity, including operation, use and maintenance of a system and work near a system, shall be carried out in such a manner as not to give rise, so far as is reasonably practicable, to danger.

o Regulation 5 – This regulation requires employers to have health and safety arrangements in place for the nature of his activities for the effective planning, organisation, control, monitoring and review of the preventive and protective measures.

• The Prevention of Fire, Explosion and Emergency Response Regulations 1995 (PFEER) specifies the goals for the preventative and protective measures to manage fire and explosion. o Regulation 19 - requires the duty holder to ensure that all plant on the installation is constructed or adapted as to be suitable for the purpose for which it is used or provided and is maintained in an efficient state, in efficient working order and in good repair.

• The Electricity at Work Regulations 1989 highlights the nature of the precautions in general terms to help duty holders achieve high standards of electrical safety in compliance with the duties imposed.

• Provision and Use of Work Equipment Regulations 1998 (PUWER) deal with the regulations for use of work equipment and machinery used every day in workplaces.

o Regulation 5 - This new regulation covers the extent and nature of inspection. It formalises the practice of systematic in-house checks on work equipment setting out general requirements for ensuring that work equipment is kept in a suitable condition. o Regulation 6 - This regulation covers the extent and nature of inspection. It formalises the practice of systematic in-house checks on work equipment. o Regulation 8 - The regulation requires the duty holder to ensure that all persons who use work equipment have available to them written instructions pertaining to the use of the work equipment. Written instructions should provide sufficient information to enable the safe operation and maintenance of the work equipment.

Relevant HSE Guidance • HSR25 – Electricity at Work Regulations (Guidance on Regulations) • HSG85 – Electricity at Work includes advice on safe working practices for managers and supervisors who control or influence the design, specification, selection, installation, commissioning, maintenance or operation of electrical equipment. • HSG107 – Maintaining Portable Electrical Equipment provides advice on maintaining portable electrical equipment to prevent danger. • HSG230 – Keeping Electrical Switchgear Safe includes guidance on the selection, use, care and maintenance of high-voltage and low-voltage switchgear • HSG253 – Safe Isolation of Plant and Equipment provides guidance on how to isolate plant and equipment safely

Action Inspectors should review relevant documentation (see Appendix 1 Pre-inspection Information Request) prior to the installation visit.

By the conclusion of the inspection, it should be possible to:

• Have an understanding of the health of the duty holders Electrical Power Systems • An acknowledgement of any action plan and some assurance that the plan will be resourced and executed. • Reveal any findings related to EPS that require enforcement action

When carrying out inspections covered by this Inspection Guide, inspectors should:

• Use the performance descriptors detailed in Appendices 2 to 6 to: o Determine the appropriate performance rating o The initial enforcement expectation o Consider how and when the issues raised during an inspection are to be closed out

Background An EPS inspection should address the Safety Management System that underpins one or more of the following elements of the EPS topics in order to assess duty holder risk management performance against relevant good practice: • hazard and risk assessment • specification, design and engineering • operation and maintenance • competence.

There may be circumstances where the inspector may decide to inspect areas other than in this guide because of specific known issues or issues identified at site during the inspection.

Other relevant Inspection Guides It should be noted that, due to the nature of Electrical Power Systems as a topic, there is a degree of cross over to many other specialist topic areas:

• The Offshore Audit, Monitoring and Review Inspection Guide - This inspection guide provides more detail on the requirements for inspecting policies and procedures which form part of the duty holder’s safety management system.

• Maintenance Management - This inspection guide provides further details on the maintenance management aspects of key topic areas.

• The Offshore SECE Management and Verification Inspection Guide.

• Cyber Security for Industrial Automation and Control Systems (IACS) Inspection Guide - This inspection guide provides details on how cyber security risk management would be inspected.

• Control of Work - This inspection guide provides information on hazard identification, Risk Assessment, Permit to Work and Isolation Management.

• Operational Risk Assessment - This inspection guide provides information and guidance on how to manage effective operational risk assessment and provides details for identifying and assessing the implications of any impairment of safety critical elements and other abnormal situations which affect major accident hazard control systems.

Specialist Advice Specialist advice should be sought from the Energy Division Electrical, Control and Cyber Security Team when considering enforcement / debate over relevant standards on any aspects of Electrical Power Systems.

Organisation

Targeting Inspections should be planned to ensure that the necessary site personnel are available and arrangements can be made to facilitate physical inspection of the system(s). OMAR will prioritise which sites to inspect and the order of inspection based on risk, duty holder performance and other intelligence. Regardless of their performance, duty holders will be subject to a degree of periodic inspection to provide public reassurance that major accident hazards continue to be managed appropriately.

Timing Inspectors should undertake Inspections as part of the agreed Intervention Plan or as determined by the EDSLT.

Recording & Reporting The duty holder performance ratings should be entered on the Inspection Rating (IRF) Tab of the relevant installation Intervention Plan Service Order. Findings should be recorded in the post inspection report and letter.

Appendix 1 - Electrical Power Systems Pre-inspection information request

1. Independent Competent Person / Independent Verification Body reports. 2. Copy of electrical performance standards 3. Single line diagram of the electrical distribution system. 4. Copy of arc flash study report. 5. Maintenance Management Strategy document. 6. Electrical Safety Rules. 7. Latest copy of UPS maintenance and battery discharge reports. 8. Copy of latest assurance and availability/reliability reports for Emergency power, emergency lighting an SECEs. 9. Maintenance Deferral procedure. 10. List of EC&I items in maintenance backlog and deferred maintenance items. 11. Any technical assessments carried out by the Electrical Technical Authority / Superintendent / Chief Engineer. 12. Obsolescence management / Asset Life extension report. 13. Any documents listed in the Safety Case that are relevant to the inspection.

Appendix 2 - Power Generation and Distribution

Fundamental Requirement The duty holder should have in place suitable arrangements to ensure that Power Generation and Distribution equipment (comprising of, but not limited to: Gas turbine / Diesel Generator / Emergency DG controls; HV/LV switchgear; AC/DC distribution systems; Transformers; HV/LV motors; power cables; UPS and battery systems) is properly designed, constructed, installed and maintained so that it does not present a risk of electric shock, burns, fire or explosion when properly used.

Success Criteria The duty holder should demonstrate that their Power Generation and distribution equipment meets the following criteria:

• Design and Installation: Equipment designed and installed in compliance with accepted industry standards such as IEC 61892, including proper selection of equipment and materials suitable for anticipated duty and environmental conditions.

• Redundancy and Reliability: Equipment designs should address equipment functionality, reliability/availability and redundancy to ensure continuous operation in line with measures detailed with PFEER 1995 regulations.

• Maintenance Records: Maintain up-to-date maintenance logs and records. A system must be in place to ensure that all power generation and electrical distribution equipment is maintained appropriately by people competent to do so, at an appropriate frequency to provide assurance that it remains in a safe condition. Equipment adequately rated for the duty it was intended to perform.

• Operational Testing: Conduct tests to ensure systems operate reliably under applicable load conditions. Ensure frequency of inspection, test, and equipment replacement are appropriate (this can be based initially on manufacturers’ recommendations, operational knowledge of equipment and/or applicable standards) and that the operation, maintenance and testing of electrical systems and equipment are carried out by people who are competent for that work.

• Management of Change: Any changes to equipment hardware, protection setting and software updates must follow duty holder’s management of change procedure to ensure that any modifications are actively risk assessed.

• Documentation: Ensure the following documents are accurate and kept up-to-date: o Electrical distribution system single line diagram and interconnection drawings o Electrical generation and distribution operating philosophy o Electrical emergency power operating philosophy and operating procedures o Equipment electrical equipment location drawings o Electrical system and equipment operating and maintenance instructions

o Switchboard and distribution board layouts and schedules o Switchboard logbooks (where used) o Earthing drawings o Electrical load lists for different operating scenarios o Electrical Safety Rules (ESR) o Electrical equipment data sheets

Key Regulations Electricity at Work Regulations 1989 Provision and Use of Work Equipment Regulations 1998 (PUWER) The Prevention of Fire, Explosion and Emergency Response Regulations 1995 (PFEER)

Supporting Standards/ACoP or Guidance See Appendix 7

Appendix 3 - Power Quality and Analysis

Fundamental Requirement The duty holder should have in place suitable arrangements to ensure that Power quality and analysis (comprising of, but not limited to: harmonic distortion; load analysis; electromagnetic compatibility and power quality monitoring) is maintained to ensure continuity of supply within acceptable tolerances and levels.

Success Criteria The duty holder should demonstrate that Power Quality and Analysis techniques are utilised where appropriate to ensure quality, stability and continuity of electrical supply (such as):

• Harmonics (capacitors, inductors and reactors): Completion of harmonic study to understand content of harmonics within power system, especially when feeding sensitive equipment such as semiconductor controlled equipment. Operators may need to take account of this in the design of electrical systems, and are advised to consider power quality issues when testing, fault finding and modification to existing electrical systems.

• Load analysis: Ensure load analysis is current and accurate for electrical distribution system configuration installed. Based on analysis, load shedding shall be applied when required in order to avoid blackout. Load shedding can be implemented by shedding of individual/groups of consumers or by appropriate separation of switchboard busbars. Care should be taken to ensure that the response time is sufficient to enable the load shedding system to perform its function and maintain a stable electrical system.

• Power Quality Monitoring: System for conducting continuous monitoring of real time power quality analysis, using appropriate devices, to check power factors and harmonics.

• Electromagnetic capability: Systems should not interfere with other equipment. For equipment in general, electromagnetic compatibility shall be achieved.

• Earthing: System earthing is provided to ensure that earth faults within an installation can be detected when a fault arises. Accordingly, as part of the duty holder’s maintenance strategy, routine inspection and testing at appropriate intervals should be carried out.

• Partial Discharge Analysis: Partial discharge (PD) analysis can enable an assessment of the condition of the insulation in high-voltage plant to be made. Non-intrusive techniques for performing PD measurements using portable instruments include measurement of transient earth voltages, ultrasonic detection and radio frequency interference (RFI detection):

• Thermographic surveys: Used to identify the surface temperature of components using infra-red thermal imaging equipment or non-contact thermometers. One of the strengths of this technique is the ability to monitor equipment while in use.

• Oil analysis: The reliable performance of oil-filled equipment depends on the characteristics of mineral insulating oil. Oil must be tested before being introduced into equipment, even if new,