Code of practice for the safe use of electricity under water

Version history

May 2024 Rev. 1.1 – Foreword and references updated; no change to content

August 2023 Rev. 1 – Addition of Section 8.9 Diving on High Power Cables

October 2010 – Initial publication

Contents

• Scope
• Introduction
• Physiology
• Derivation of Values Used
• Definitions and Explanations
• Basic Assumptions
• Ensuring Electrical Safety
• Application Scenarios
• Appendix 1 – Bibliography
• Appendix 2 – Calculation of ‘Safe Distance’
• Appendix 3 – Residual Current Devices
• Appendix 4 – Salinity of Water
• Appendix 5 – Design Considerations
• Appendix 6 – Batteries
• Appendix 7 – Installation Practices
• Appendix 8 – Methods for Protection Against Shock
• Appendix 9 – Summary Table of Safe Practices

Summary

This Code deals with the various common hazards which may arise from the use of electricity under water. The most obvious of these is electric shock and the prevention of this is the primary intent of the Code.

In addition, degradation of electrical insulating material by heat can result in the emission of toxic or explosive products, and hot surfaces or electric arcs from faulty equipment or switching devices can ignite some gas mixtures and pollute the diver’s breathing gas supplies. Information on the prevention of these hazards is included in the Code.

All other risks associated with the use of electric power under water (mechanical risks, non-electric burns, ionising radiation, and generation of sound, ultra-sound and shock waves) are excluded.

The Code covers all types of electrical equipment used by the diver or employed for his benefit and under his control or that of his support team. In addition, it covers any electrical equipment or supply which the diver may be asked to work on or which is in the vicinity of the diver while he is working or gaining access to the work site.

The Code considers the risks arising from the various environments encountered. It makes recommendations for the selection, installation and maintenance of electrical apparatus used to enable an adequate level of safety to be achieved.

The Code does not address electrical safety above water as this subject is adequately covered in other documents. However, personnel involved in maintenance or modification of surface equipment used in connection with electricity under water should remember that the measures outlined in this Code are designed to protect man under water and may not on their own provide adequate protection for surface crew. The question of surface back-up supplies and levels of redundancy is also not covered.

Published information on insulation materials is normally based on information relating to the decomposition of materials and the physiological effect of the decomposition products at normal atmospheric pressures. The effect of higher pressure on these processes is not fully known and this should be considered by designers and material specifiers.

The recommendations are based on a number of assumptions (see section 6) and anybody using this Code as a means of ensuring the electrical safety of a diver should check that the assumptions used are applicable to the specific situation which they are considering.