Introduction High Voltage Safety Marine Electrical Cables and Wires W. Maes Department of Marine Engineering Antwerp Maritime Academy HV, 2017 Willem Maes High Voltage Safety
Introduction Outline Introduction 1 Willem Maes High Voltage Safety
Introduction Introduction Transport of electric energy takes place over conductors. For short distances we can use solid bars. For larger distances cables are used. Willem Maes High Voltage Safety
Introduction Marine Electric Cabling Willem Maes High Voltage Safety
Introduction Conductors in Electrical Cables Marine cables use a stranded conductor of 7 or more wires. Willem Maes High Voltage Safety
Introduction Material used for conductors Copper ρ = 0 , 0175 Ω mm 2 / m Aluminium ρ = 0 , 029 Ω mm 2 / m Willem Maes High Voltage Safety
Introduction The main acceptable types are: low smoke low toxic Willem Maes High Voltage Safety
Introduction PVC cables commercially attractive generate toxic and corrosive gases during a fire Willem Maes High Voltage Safety
Introduction Low smoke cable types low mechanical properties stress while being pulled is considerably lower than PVC Willem Maes High Voltage Safety
Introduction Electric Field Willem Maes High Voltage Safety
Introduction Electric Field Concentration Willem Maes High Voltage Safety
Introduction Electric Field Concentration Willem Maes High Voltage Safety
Introduction Dielectric stress in a single core cable Under operating conditions, the isolation of a cable is subject to electrostatic forces. This is known as dielectric stress. Under influence of dielectric stress isolation can deteriorate. Willem Maes High Voltage Safety
Introduction Dielectric Strength Dielectric Strength is the material’s ability to withstand voltage breakdown. Is expressed in Volts (V) or Kilo volts (KV) Willem Maes High Voltage Safety
Introduction Normal three-core power cable Willem Maes High Voltage Safety
Introduction Fire resistant screened power cable Willem Maes High Voltage Safety
Introduction Fire resistant power cable Willem Maes High Voltage Safety
Introduction Fire resistant control cable Willem Maes High Voltage Safety
Introduction Double screened (EMC) power cable Willem Maes High Voltage Safety
Introduction Overall screened cable Willem Maes High Voltage Safety
Introduction Cables for Marine use Cables for marine use differ from those used for on-shore installations: Core is not solid but consist of stranded conductor of 7 or more wires to cope with the vibrating environment. Cables in a marine environment must be fixed to the cable supports. Flexible cables for cranes or telescopic supported wheelhouses are fixed to movable cable trays. Willem Maes High Voltage Safety
Introduction Cables for Marine use Cables for marine use differ from those used for on-shore installations: Core is not solid but consist of stranded conductor of 7 or more wires to cope with the vibrating environment. Cables in a marine environment must be fixed to the cable supports. Flexible cables for cranes or telescopic supported wheelhouses are fixed to movable cable trays. Willem Maes High Voltage Safety
Introduction Cables for Marine use Cables for marine use differ from those used for on-shore installations: Core is not solid but consist of stranded conductor of 7 or more wires to cope with the vibrating environment. Cables in a marine environment must be fixed to the cable supports. Flexible cables for cranes or telescopic supported wheelhouses are fixed to movable cable trays. Willem Maes High Voltage Safety
Introduction Flexible Cables Flexible cables shall consist of flexible conductors, stranded with 19 or more wires and special flexible insulating materials. The cables must stay flexible at lower temperatures (below 0) Willem Maes High Voltage Safety
Introduction Exception Cables with solid conductors up to 2.5 mm 2 can be used in ship’s accommodations. Willem Maes High Voltage Safety
Introduction Single conductor cables Single conductor AC cables in systems rated more than 20A arrangements are to be made to account for the harmful effect of electromagnetic induction: the cable is to be supported on non fragile insulators The cable armoring or any metallic protection must be non magnetic and earthed on mid span or supply end only When single core cables pass a bulkhead the sum of the currents trough this penetration must be 0 Willem Maes High Voltage Safety
Introduction Single conductor cables Single conductor AC cables in systems rated more than 20A arrangements are to be made to account for the harmful effect of electromagnetic induction: the cable is to be supported on non fragile insulators The cable armoring or any metallic protection must be non magnetic and earthed on mid span or supply end only When single core cables pass a bulkhead the sum of the currents trough this penetration must be 0 Willem Maes High Voltage Safety
Introduction Single conductor cables Single conductor AC cables in systems rated more than 20A arrangements are to be made to account for the harmful effect of electromagnetic induction: the cable is to be supported on non fragile insulators The cable armoring or any metallic protection must be non magnetic and earthed on mid span or supply end only When single core cables pass a bulkhead the sum of the currents trough this penetration must be 0 Willem Maes High Voltage Safety
Introduction Fire resistant cables Must remain functional under fire conditions. Have a similar construction as other cables, but are provided with an additional layer of mineral insulation around the conductors, in this case mica. Willem Maes High Voltage Safety
Introduction Application of fire resistant cables When the circuit have to remain in service under fire conditions. emergency lighting fire detection communication circuits fire pump fire safety shut down circuits Willem Maes High Voltage Safety
Introduction Application of fire resistant cables When the circuit have to remain in service under fire conditions. emergency lighting fire detection communication circuits fire pump fire safety shut down circuits Willem Maes High Voltage Safety
Introduction Application of fire resistant cables When the circuit have to remain in service under fire conditions. emergency lighting fire detection communication circuits fire pump fire safety shut down circuits Willem Maes High Voltage Safety
Introduction Application of fire resistant cables When the circuit have to remain in service under fire conditions. emergency lighting fire detection communication circuits fire pump fire safety shut down circuits Willem Maes High Voltage Safety
Introduction Cable selection tables Willem Maes High Voltage Safety
Introduction Cable selection tables Correction factor for ambient air temp of 45 C Willem Maes High Voltage Safety
Introduction Cable selection tables Correction factors for bunching of cables or when the numbers of conductors in a cable exceeds 4 may also be applied and class rules must be consulted for the corresponding values. ABS pg654 Willem Maes High Voltage Safety
Introduction Cable selection tables Codes are printed on the outside, according to the production standard Willem Maes High Voltage Safety
Introduction Cable trays and cable fixing fixed cable trays. Willem Maes High Voltage Safety
Introduction Cable trays and cable fixing flexible cable trays. Willem Maes High Voltage Safety
Introduction Pipe and cable tunnel Willem Maes High Voltage Safety
Introduction Minimum internal radius of bends Willem Maes High Voltage Safety
Introduction Minimum internal radius of bends An average figure of 6 times the overall diameter is a reasonable rule of thumb. Above 1000V the figure lies between 15 times the overall diameter for multicore and 20 for single-core cables Willem Maes High Voltage Safety
Introduction High voltage cables Willem Maes High Voltage Safety
Introduction High voltage cables must be segregated from low voltage cables. Control cables must be segregated from all power cables. Willem Maes High Voltage Safety
Introduction Minimum distances cable supports Willem Maes High Voltage Safety
Introduction Cables are normally fixed with Tie-wraps. These tie wraps must be UV resistant. When cables are mounted on vertical or overhead cable-trays steel cable band are used. When single-core or high voltage cables are involved non magnetic materials should be used (stainless-steel). Willem Maes High Voltage Safety
Introduction Cables are normally fixed with Tie-wraps. These tie wraps must be UV resistant. When cables are mounted on vertical or overhead cable-trays steel cable band are used. When single-core or high voltage cables are involved non magnetic materials should be used (stainless-steel). Willem Maes High Voltage Safety
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