Shielded electrical cable joints and terminations and sleeve and method for forming same

A shielded electrical cable termination comprising:

• (a) a cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an innermost stress grading layer having an at least partly resistive character and extending from the exposed conductor to overlap the cable shield, a conductive outer layer electrically contacting the stress grading layer at said overlap with the cable shield, and an insulating layer that separates the stress grading layer and the conductive layer in the region between said overlap and the exposed conductor.

A shielded electrical cable termination comprising:

• (a) a cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an inner insulating layer having a first portion of substantially uniform minimum thickness overlapping the cable shield by an amount at least equal to said minimum thickness, a contiguous second portion of gradually increasing thickness to provide stress control, and a contiguous third portion of substantially uniform maximum thickness extending to the region of the exposed conductor, and an outer conductive layer overlapping the cable shield, radially spaced apart from the cable shield, and electrically connected to the cable shield at a distance from the end of the cable shield at least equal to said minimum thickness.

A shielded electrical cable termination comprising:

• (a) a cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an insulating inner layer, a conductive outer layer electrically connected to the cable shield and an innermost stress grading layer having at least partly resistive character and extending from the exposed conductor to the cable shield;
• said insulating layer having a first portion of substantially uniform minimum thickness overlapping the cable shield by an amount at least equal to said minimum thickness, a contiguous second portion of gradually increasing thickness to provide stress control, and a contiguous third portion of substantially uniform maximum thickness extending to the region of the exposed conductor, and the outer conductive layer overlapping the cable shield, radially spaced apart from the cable shield, and electrically connected to the cable shield at a distance from the end of the cable shield at least equal to said minimum thickness.

A shielded joint between two shielded electric cables comprising:

• (a) two shielded electrical cables, each cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer;
• and
• (b) a tubular enclosure comprising a tubular protective sleeve comprising an insulating inner layer and a conductive outer layer electrically connected to and overlapping each cable shield, the conductive outer layer being spaced from each cable shield by the insulating layer, wherein the insulating layer has a substantially uniform wall thickness along its entire length and overlaps each cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying that cable shield end, and wherein electrical connection between the conductive outer layer and each cable shield is made at a point on that cable shield at a distance from the end of that cable shield at least equal to the thickness of the portion of the insulating layer overlying that cable shield end.

A joint between two shielded electrical cables, comprising

• (a) two cables, each comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an innermost stress grading layer having an at least partly resistive character and extending from the exposed conductor to overlap each cable shield, a conductive outer layer electrically contacting the stress grading layer at said overlap with each cable shield, and an insulating layer that separates the stress grading layer and the conductive layer in the region between said overlap and the exposed conductor.

A cable joint between two shielded electrical cables, comprising:

• (a) two cables, each comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an inner insulating layer having a first portion of substantially uniform minimum thickness overlapping each cable shield by an amount at least equal to said minimum thickness, a contiguous second portion of gradually increasing thickness to provide stress control, and a contiguous third portion of substantially uniform maximum thickness extending to the region of the exposed conductor, and an outer conductive layer overlapping each cable shield, radially spaced apart from each cable shield, and electrically connected to each cable shield at a distance from the end of that cable shield at least equal to said minimum thickness.

A cable joint between two shielded electrical cables, comprising:

• (a) two cables, each comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose a length of the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose a length of the dielectric layer, and
• (b) an enclosure comprising a tubular protective sleeve comprising an insulating inner layer, a conductive outer layer electrically connected to each cable shield and an innermost stress grading layer having at least partly resistive character and extending from each exposed conductor to each cable shield;
• said insulating layer having a first portion of substantially uniform minimum thickness overlapping each cable shield by an amount at least equal to said minimum thickness, a contiguous second portion of gradually increasing thickness to provide stress control, and a contiguous third portion of substantially uniform maximum thickness extending to the region of the exposed conductors, and the outer conductive layer overlapping each cable shield radially spaced apart from each cable shield, and electrically connected to each cable shield at a distance from the end of each cable shield at least equal to said minimum thickness.

A protective sleeve for a cable termination or splice which comprises a dimensionally recoverable extruded tubular article having an innermost stress grading resistive layer, an insulating inner layer and a conductive outer layer, wherein the insulating layer has a substantially uniform wall thickness along its entire length.

A method of protecting a termination of a shielded electrical cable against electrical stress, the cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose the dielectric layer, the method comprising the steps of (a) placing on the termination in conforming engagement with the termination a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer, said sleeve also being provided with an innermost stress grading layer having an at least partially resistive character extending from the exposed conductor to the cable shield, such that the insulating layer and the stress grading layer overlap the cable shield, the insulating layer overlapping the cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying the cable shield end and (b) electrically connecting the conductive outer layer and the cable shield at a point on the cable shield at a distance from the end of the cable shield at least equal to the thickness of the portion of the insulating layer overlying the cable shield end.

A method of protecting a termination of a shielded electrical cable against electrical stress, the cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose the dielectric layer, the method comprising the steps of (a) placing on the termination in conforming engagement with the termination a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer, such that the insulating layer overlaps the cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying the cable shield end and (b) electrically connecting the conductive outer layer and the cable shield at a point on the cable shield at a distance from the end of the cable shield at least equal to the thickness of the portion of the insulating layer overlying the cable shield end.

A method of protecting a termination of a shielded electrical cable against electrical stress, the cable comprising a conductor, a dielectric layer which surrounds the conductor, and an electrically conductive shield which surrounds the dielectric layer, the method comprising the steps of selecting for the termination a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer, and placing the enclosure on the termination so that the insulating layer overlaps the cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying the cable, so that the conductive outer layer overlaps and is radially spaced apart from the cable shield, and so that electrical connection between the conductive outer layer and the cable shield is made at a point on the cable shield at a distance from the end of the cable shield at least equal to the thickness of the portion of the insulating layer overlying the cable shield end.

A method of protecting a termination of a shielded electrical cable against electrical stress, the cable comprising a conductor, a dielectric layer which surrounds the conductor, and an electrically conductive shield which surrounds the dielectric layer, the method comprising the steps of selecting for the termination a conforming enclosure comprising a protective sleeve comprising an innermost stress grading layer having at least partially resistive character, an insulating inner layer and a conductive outer layer, and placing the enclosure on the termination such that the insulating layer overlaps the cable shield end, the stress grading layer is electrically connected to the cable shield, and electrical connection between the conductive outer layer and the cable shield is made at a point on the cable shield at a distance from the end of the cable shield at least equal to the thickness of the portion of the insulating layer overlying the cable shield end and beyond the end of the insulating layer overlying the cable shield end.

A method of protecting a joint between two shielded electrical cables against electrical stress, each cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose the dielectric layer, the method comprising the steps of (a) placing on the joint in conforming engagement with the joint a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer, said sleeve also being provided with an innermost stress grading layer having an at least partially resistive character extending from the exposed conductor to each cable shield, such that the insulating layer and the stress grading layer overlap each cable shield, the insulating layer overlapping the cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying that cable shield end and (b) electrically connecting the conductive outer layer and each cable shield at a point on that cable shield at a distance from the end of that cable shield at least equal to the thickness of the portion of the insulating layer overlying that cable shield end.

A method of protecting a joint between two shielded electrical cables against electrical stress, each cable comprising a conductor, a dielectric layer which surrounds the conductor and which has been cut back to expose the conductor, and an electrically conductive shield which surrounds the dielectric layer and which has been cut back to expose the dielectric layer, the method comprising the steps of (a) placing on the joint in conforming engagement with the joint a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer such that the insulating layer overlaps each cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying that cable shield end and (b) electrically connecting the conductive outer layer and each cable shield at a point on that cable shield at a distance from the end of that cable shield at least equal to the thickness of the portion of the insulating layer overlying that cable shield end.

A method of protecting a joint between two shielded electrical cables against electrical stress, each cable comprising a conductor, a dielectric layer which surrounds the conductor, and an electrically conductive shield which surrounds the dielectric layer, the method comprising the steps of selecting for the joint a conforming enclosure comprising a protective sleeve comprising an insulating inner layer and a conductive outer layer, and placing the enclosure on the joint so that the insulating layer overlaps each cable shield by an amount at least equal to the thickness of the portion of the insulating layer overlying that cable, so that the conductive outer layer overlaps and is radially spaced apart from each cable shield, and so that electrical connection between the conductive outer layer and each cable shield is made at a point on that cable shield at a distance from the end of that cable shield at least equal to the thickness of the portion of the insulating layer overlying that cable shield end.

A method of protecting a joint between two shielded electrical cables against electrical stress, each cable comprising a conductor, a dielectric layer which surrounds the conductor, and an electrically conductive shield which surrounds the dielectric layer, the method comprising the steps of selecting for the joint a conforming enclosure comprising a protective sleeve comprising an innermost stress grading layer having at least partially resistive character, an insulating inner layer and a conductive outer layer, and placing the enclosure on the joint such that the insulating layer overlaps each cable shield end, the stress grading layer is electrically connected to each cable shield, and electrical connection between the conductive outer layer and each cable shield is made at a point on that cable shield at a distance from the end of that cable shield at least equal to the thickness of the portion of the insulating layer overlying that cable shield end and beyond the end of the insulating layer overlying that cable shield end.