Canada Wire and Cable Limited

Norscan Instruments Ltd.

David E Vokey

John P McNaughton

Wayne E Domenco

Apparatus for monitoring electrical cables for the presence of moisture within the cable along the full length of the cable and at specific points such as splices along its length comprises a pair of dielectrically separated conductors arranged along the length of the cable for communicating between a central station and remote stations along the length of the cable at the specific points to be monitored. The remote stations each include a further dielectrically separated pair of conductors for sensing moisture at the point and signals along the first pair of conductors to the central station. The central station detects moisture by an increase in current in the conductors and also detects a signal from remote stations. Branch cables spliced into the main cable include dielectrically separated conductors also spliced into the main conductors with the remote station at the splice including means for disconnecting the branch cable conductors from the main cable conductor under control from a signal from the central station.

Apparatus to monitor electrical cables, including splice joints and the

A cable assembly for detecting the ingress of water inside a cable is disclosed. The cable assembly comprises a moisture detecting tape constructed of two parallel bare conductors laminated to an insulating substrate. The tape thus constructed is applied in an open helix around the conductor core of a cable. A suitable plastic jacket is extruded over the cable core and the moisture detecting tape. A shielding tape may also be applied over the cable core and the moisture detecting tape prior to extrusion of the overall plastic jacket. The cable thus constructed with the integral moisture detecting tape is adapted for connection to a suitable sensing apparatus at one end, and should moisture enter the cable as a result of damage to same, the electrical characteristics of the detecting tape would change and such change will result in a measurable conductance between the conductors of the moisture detecting tape. The ingressing water is thus sensed prior to penetrating and compromising the cable core. Standard bridge techniques are employed to determine the distance of the fault from the ends of the cable.

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Winnipeg, Canada

David E Vokey