Cable joint protection

Wire and cable joints are often protected by the use of irradiated PVC heat-shrink sleeving. 

So that the function of the spark gap isolators is not cancelled, cables with lightning protection must have insulated sleeves installed at their ends, in addition to the spark gap isolators, so that the metal sheathing or the shield that is connected at soldered joints to the lightning reinforcement is also separated from the operational ground of the building (foundation ground) and from the ground at the remote end. 

The results of these experiments have been considered by the Joint Committee for the Co-ordination of the Cathodic Protection of Buried Structures and, in view of the various types of buried structures concerned and the circumstances in which field tests are conducted, the Committee decided not to amend its provisional recommendation that when cathodic protection is applied to a buried structure the maximum permissible potential change in the positive direction on a nearby pipe or cable should be 20 mV. If there is a history of corrosion on the unprotected installation no detectable positive change in structure/soil potential should be permitted. These criteria of interaction have been adopted in the British Standard Code of Practice for Cathodic Protection . 

Locating and Bonding when cathodic protection is applied to an existing jointed pipeline, all joints must be located without digging up the pipe. On location, each joint is exposed and an electrically conducting bond (usually galvanised steel strip or copper cable) is welded into position. 

High-temperature resistance In building structures to minimise the risk of fire e.g. expansion and compression joints, construction gaps, fire protection panels, fire doors around cable, pipe penetration... 

MAJOR PRODUCT APPLICATIONS rubber, adhesives, protective coatings, traffic paint, joint compounds, plastics, cables, belting, footwear, plant lining, tires... 

Fibre-optic cables look like steel wire armour cables (but of course they are lighter) and should be installed in the same way, and given the same level of protection, as SWA cables. Avoid tight-radius bends if possible and kinks at all costs. Cables are terminated in special joint boxes which ensure cable ends are cleanly cut and butted together to ensure the continuity of the light pulses. Fibre-optic cables are Band I circuits when used for data transmission and must therefore be segregated from other mains cables to satisfy the lET Regulations. 

The L S re.search will be watched with interest, It has already been noted that a post-tensioned bridge collapsed in Wales a few years ago. The bridge had no waterproofing on the deck, the ducts were poorly grouted and salt got into the joint.s between segments and corroded the steel. The UK DoT has no idea how many bridges are in a comparable condition in the UK, Further failures are therefore possible. As cathodic protection cannot protect the cables inside ducts on post-tensioned structures, it has limited applicability for protecting such structures,... 

Many utilities have now replaced paper lead cables by plastics cable for low-voltage power distribution. Since each core has a plastics sheath no additional protection is required at the termination. However, a heat-shrinkable glove is still required such that water cannot penetrate into the body of the cable. If this is not done the cable acts as a water pipe allowing water to be transmitted into terminations and joints, which could result in failure. 

Steam hose leading to a steam hammer or jet pipe shall be securely attached to the hammer with an adequate length of at least V4-inch diameter chain or cable to prevent whipping in the event the joint at the hammer is broken. Air hammer hoses shall be provided with the same protection as required for steam lines. 

To terminate optical cable in the field, a fiber optic pigtail may be used. A pigtail is typically a single-or multi-fiber cable that has been connectorized at the factory on one end only. The other end remains nonterminated and is spliced to the installed cable. This joint can be either a fusion splice or a mechanical splice. After splicing, the splice point is placed inside a protective splice tray, which is then housed in fiber... 

Sections 5,6 and 7 cover the selection, sizing and installation of cables and their protection from damage. It includes the requirements for the location of mechanically unprotected cables buried in the structure, under floorboards or underground and in Table 15 reproduces the NJUG (National Joint... 

Flexible metallic conduit should have a non-metallic inner sheath or be suitably designed so that movement cannot cause abrasion of the cables. Flexible metallic conduit is not a suitable protective conductor. A flexible cable conductor should be used for this purpose to ensure earth continuity between the fixed conduit and apparatus, and the flexible conduit joints should be earth bonded at both ends. 

PE insulation tapes are used both at 80°C and at low temperatures to cover joints and welds in wires and cables (with no additional protection). 

Jointing and termination are essential procedures for the efficient and proper transmission and distribution of power through cables. To extend the cable, frequent joints are needed. Also, the end terminations during storage need to be protected. Heat shrinkable and radiation crosslinkable polymeric materials may be used for this purpose. 

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