The first units from the new range are 250A three-phase fully-interlocked switch sockets and plugs, bound for the Dubai aluminium smelter.

Industrial connectors of this size are almost invariably used in inhospitable environments such as dockyards, industrial plants and railways explains Stephen Cheek, Sales Director for LPA Industries. Frequently they are required for use in tropical environments.

LPA's new switch socket has an lP66 protection rating. The MEM S-Type fuse combination switch is enclosed in a fabricated stainless steel enclosure with the cast aluminium socket mounted below. A double interlock system ensures that the FCS cannot be switched ON unless a plug is fully inserted and the plug cannot be withdrawn unless the switch is OFF.

In Dubai, the switch sockets are being used to supply three-phase power to smelting pots and other heavy electrical loads in the Dubal smelter. Their use will allow these loads to be disconnected for repair and maintenance without disrupting the supply to other plant.

The new LPA switch sockets replace the former Niphan range of industrial metalclad switch sockets and are available in 160A, 200A and 250A ratings with three-, four- or five-pole sockets. The four-pole MEM S-type fuse combination switch is rated 350A in air and is fitted with 250A MEM Paramount HRC fuses.

LPA needed a fused switch that would provide adequate switching capability and overload protection and could be interlocked mechanically with its five-pole industrial connector. A special interlock mechanism has been developed by LPA. This is connected to the operating shaft of the FCS and passes through a water-tight entry in the enclosure to engage with the plug.

The switch socket assembly comprises a fabricated stainless steel enclosure housing the fuse combination switch. A separate stainless steel cable entry box with gland plates for top or side entry is mounted directly above the enclosure and the heavy-duty five-pin LPA socket is mounted below. Gaskets and 0-ring seals ensure full lP66 protection -- i.e. complete protection against ingress of dust (IP6X) and protection against jets and waves including conditions on ships' decks (IPX6). The switch can be padlocked in the OFF position.

MEM Low Voltage Products is one of the few switchgear manufacturers offering both circuit-breaker and fuse technology. The choice of fuse combination switches rather than moulded-case circuit-breakers for the new LPA switch fuse range was based largely on the preference of clients like Dubal for a mechanical interlock system. At the same time, HRC fuses provide a high short-circuit breaking capacity.

"We chose MEM because it is a highly respected British manufacturer offering a range of quality switchgear which complements the high specification of our industrial plugs and sockets" says Kevin Cornfoot, Marketing Director of LPA Industries. "We are developing a relationship with MEM as a preferred supplier" he says.