In this article, the recommendations for electrical safety and standardization at marinas are discussed. The 16th Edition of the Wiring Regulations does not contain additional requirements for Marinas; but the general requirements apply and the IEE gives guidance in Guidance Note 7.
The 17th edition of BS 7671, due to be published in 2008, includes marinas as a special location (Section 709) and will include requirements similar to those discussed below.
A marina is a facility for the mooring of leisure craft and has fixed wharves, jetties, piers or a pontoon arrangement capable of berthing one or more leisure craft. A leisure craft is a boat, vessel, yacht, motor launch, houseboat or other floating craft used exclusively for sport or leisure and a houseboat is a floating decked structure which is designed or adapted for use as a place of permanent residence often kept in one place on inland water.
An electrical installation at a marina consists of the equipment which supplies the leisure craft or houseboat and the installation is subject to additional recommendations because of electrical safety issues and in order to provide for standardisation of power facilities.
The recommendations do not apply to the parts of the electrical installations in offices, workshops, leisure accommodation etc. which form part of the marina complex, to the supply of houseboats if they are directly supplied from the public network, or to the internal electrical installations of leisure craft or houseboats. Additional requirements are considered necessary because of increased electric shock risks associated with a wet environment, reduction in contact resistance and contact with earth potential.
In addition, the environment of a marina is harsh for electrical equipment. The water, salt, and movement of structures accelerate deterioration of the installation. The presence of salt water, dissimilar metals and a potential for leakage currents increases the rate of corrosion. There is a real possibility of electrical equipment being splashed or even submerged. Flammable fuel may be present.
A risk associated with an electrical supply to a craft at a marina includes the possibility of an open circuit fault of the PEN conductor were a PME supply to be used. This would raise the potential of all metalwork (including that of the craft, if connected) to a dangerous level above true earth and hence the connection of a neutral conductor to the metal body of a boat or caravan is specifically prohibited in legislation (Electricity Safety, Quality and Continuity Regulations (ESQCR) Regulation 9(4)).
Further risks include the inability to establish an equipotential zone external to the craft, the possible loss of earthing due to long supply cable runs, connecting devices exposed to weather and flexible cord connections liable to mechanical damage.
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(Originally published in Wiring Matters, by John Ware)