Cable Change Box, Plug-In, 2000A

Overview

When a vessel is in dock for servicing or refit, significant levels of temporary power can be required, as the ship’s on-board engines are usually shutdown. The Royal Navy Dockyards are very aware of this issue and minor power requirements can be met by Dockside Service Units, which are installed around the docks. However, when a vessel requires significant amounts of power, this is usually provided by Cable Change Boxes (CCB), which are permanently installed assemblies with a hard wired incoming supply and plug-in outgoing connections (hard wired outging terminations can also be provided).

On a recent project we manufactured a total of 20 no. Cable Change Boxes, each rated at 2000A and each fed from a dedicated 440V, 60Hz, 3 wire supply. The assemblies are designed to accept incoming cable arrangements of either 2 no. 630mm2 single cables per phase or 6 no. 3C 240mm2 cables. Incoming cables enter from below via a brass gland plate. The incoming terminals are mounted behind a clear, IP rated, screw-fixed, polycarbonate cover. An external earth stud is provided for the connection of a CPC cable.

On the outgoing side, 3 no. 800A Powersafe source connectors per phase are fitted. Access to the connectors is via the main hinged door, which can be closed and locked once the connectors have been mated, to prevent unauthorised connection or disconnection. In addition, the main door incorporates a Castell locking system, which is interlocked with the supply MCCB. Once the door is locked (and the Castell key removed) the door can only be opened when the upstream power has been isolated. An emergency stop button is also fitted, which operates the supply MCCB.

The CCB itself is intended to be permanently installed on the dockside. The enclosure is made from grade 316L stainless steel with a painted finish, and the enclosure provides protection to IP55. The plug-in outgoing flexible cables exit the enclosure through an aperture in the underside, and brushed strips are incorporated, which restrict the ingress of foreign bodies without impeding cable access. The enclosure is mounted on a heavy duty stand, which has a hot dip galvanized finish.

CCBs are made to order assemblies and are typically rated between 1000A and 3000A.