Cables paper-insulated lead-sheathed

Paper insulated lead sheathed cables for voltages up to 33 kV Tests on cables and their accessories 692/1994 BS 6480/1997 -... 

In the main, only competent people should be used for making joints and connections in wiring systems. Skilled cable jointers, for example, should be employed to make joints in paper-insulated lead-sheathed steel... 

In the past, there were fewer accidents because buried cables were better protected. Most of the supply authorities used paper-insulated, lead-sheathed, single-wire or steel-tape armoured and served cables and very often protected them with cable tiles. For economic reasons cable tiles are seldom used now and many of the mains laid in recent years are unarmoured CNE cables with plastic insulation and sheathing, such as PVC and cross-linked polyethylene (XLPE). The outer concentric conductor, which is the earthed neutral, is copper or aluminium tape and consequently more vulnerable to damage than a steel-wire-armoured cable. Every year more new mains cables of this type are laid so the resultant hazard to excavators is growing and more accidents can be expected to occur unless the construction industry becomes more effective at taking precautions against striking buried cables. 

BS6480 Power cables, impregnated paper - insulated, lead or lead alloy sheathed. 

Telephone Cable Plug Compounds - Co-reacts with epoxy and amines to form dam in lead-sheathed cable and polyethylene covered cable. Prevents moisture intrusion and permits pressurization of cable. Does not interfere (electrically) with transmission with paper insulated conductors. 

In the past the copper conductor pairs in telecommunication cables were insulated with paper pulp, and the outer sheath, which serves as an electric shield and provides corrosion-resistant physical protection, was made of a lead alloy containing 1.0 mass% antimony. The connections (splices) between the individual conductors were enclosed either in lead sleeves or in closures consisting of two galvanized half shells of gray cast iron, held together with stainless steel bolts and nuts. Although there is still a considerable amount of lead-sheath cable, lead sleeves, and galvanized cast iron closures, the modem telecommunication cable plant relies heavily on plastics as the material of constmction. 

Older installations usually have an armoured paper insulated and lead sheathed service cable providing an SNE supply. The consumer s earthing terminal should be connected to the lead sheath of this service cable. Look out for earthing to the incoming water service pipe, which is no longer permitted. Check that the size of the earthing conductor complies with BS 7671, section 543, or, if the consumer has his or her own buried earth electrode, is in accordance with both sections 542 and 543. 

This type of cable comprises conducting cores insulated with paper or plastics insulation or dielectric. Around the outside is a lead or nowadays more commonly aluminium sheath with finally an outer armour. This is the type of cable which provides the normal house or office service. The house service version has one phase and one neutral core, but in the distribution box the incoming cable will contain four or five cores. 

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