The case for open installation for metal-sheathed cables, with some notes on construction

The paper is an extension of the author's earlier paper which gave details of the incidence, together with an explanation, of the large amount of sheath fracture experienced with lead and lead-alloy sheathed cables run on hooks. The conclusion was reached that, with correct design, satisfactory life can be obtained for cables so installed. As a result of that work the author has been led to the further conclusion, briefly recorded in the discussion on the earlier paper, that, contrary to the common view, installation on spaced supports is preferable to any other method where this alternative is available. The reasons for this conclusion are discussed, and the consideration of construction on spaced supports is extended both as to method and analysis of behaviour. A new method, employing pairs of supports instead of single ones, is described. The principles and conclusions are applicable to lead- or aluminium-sheathed cables of solid, oil-filled, or gas-pressure type, and to communication cables.