Abstract: A dimensionally-recoverable article comprising a hollow resilient member which has been expanded to a dimensionally unstable configuration in which it is retained by a keeper positioned between and separating two parts of the hollow member away from the path of recovery thereof. The keeper is preferably made from a fusible or chemically degradable material so that it can be removed, for example, by heating or chemical treatment to allow the hollow member to recover towards its original configuration. One preferred form of article is a radially-expanded longitudinally split tube having the keeper positioned within the split. Such an article may be used as a connector to secure an earth lead to the sheath of a mineral-insulated cable.

Abstract: Electrical connections to line substrates, such as cables, are made by employing a radially shrinkable coil member which is positioned about the substrate in an expanded form and is then caused or allowed to revert to a smaller radius so that it grips the substrate. In preferred embodiments the coil member is made from a heat-recoverable material or is made from a resilient material which is held in an expanded form by a disburdenable material, e.g. a fusible material such as solder, which is subsequently removed, deformed or destroyed so as to cause connection. The devices are especially suitable for connecting earth leads to the sheaths of mineral insulated cables in the vicinity of terminations and splices thereof.

Abstract: An electrical insulating material having anti-tracking properties has incorporated therein an erosion inhibiting fluorine-substituted compound. The electrical insulating material comprises a polymeric material having an anti-tracking filler and the fluorine-substituted compound is a hydrophobic, non-ionic compound having a fluorine-substituted aliphatic carbon chain linked to a group having an affinity for the polymeric material and/or the anti-tracking filler. The electrical insulating material may be used in high voltage applications where it is necessary to resist erosion and/or control leakage currents.

Abstract: A method of recovering a heat-recoverable article onto a hollow substrate, the heat-recoverable article and the substrate each having at least one open end. The method comprises positioning the substrate between a rigid member and the heat-recoverable article, the substrate being positioned in the direction of recovery of the heat-recoverable article and at least part of the rigid member being in contact with the substrate. The heat-recoverable article is then treated to cause recovery thereof. The hollow substrates to which the method of the invention is applied are those which would be distorted if a heat-recoverable article were recovered onto them in the absence of a rigid member. Advantageously, the heat-recoverable article is a heat-shrinkable sleeve and in this case the rigid member is positioned inside the hollow substrate.

Abstract: A polymer composition containing silicon carbide of a critical maximum average particle size can be processed into heat-shrinkable articles possessing nonlinear electrical resistance characteristics. An embodiment of the invention provides a heat-shrinkable article comprising a laminate of a layer of elastomer, including silicon carbide particles, and a layer of a heat-shrinkable polymeric material. The elastomeric layer may be a blend of a rubbery polymer and a low density polyethylene having dispersed therein particulate silicon carbide of particle size finer than about 300 grit.