Abstract: An electric busbar installation comprises at least one busbar comprising a rigid bare elongate conductor housed within and rigidly secured to and spaced from a rigid tube, arranged with its axis substantially vertical by longitudinally spaced rigid insulators, the space between the busbar and the tube containing an electrically insulating fluid which is in direct contact with the bare conductor of the busbar, at least one duct which is in thermal association with the bare conductor throughout the length of the busbar and which forms part of a closed circulatory system for evaporable refrigerant; and interconnected in the circulatory system, condensing means for receiving evaporated refrigerant from, and for delivering liquid refrigerant to, the duct.

Abstract: An oil-filled electric cable installation, in which oil when flowing outwardly from the cable to a pressure-maintaining oil tank it passes through a percolating filter, preferably of an active material, to remove particulate and/or dissolved impurities. A one-way return passage bypasses the filter so that maintenance of pressure is not impaired, and if required a high-pressure bypass may be used to protect the filter from unusually high pressures.