Link Box is electrically and mechanically one of the integral accessories of HV underground cable Bonding System, associated with HV XLPE power cable system.

Briefly the Bonding System is so designed that the cable sheaths are bonded and earthed/grounded in such a way as to eliminate or reduce the circulating sheath currents and to limit standing induced sheath voltages for human safety , and also during any internal fault or short circuit of the system , short circuit current flows directly to the earth through link box.

The induced sheath currects are undesirable because they cause heat losses, which reduce the current carrying capacity, a very important design consideration in a big power transmission cable system investment.

Generally Link Box implies close association with insulated joints (interrupted sheathing design) of a long power line serving as a protective housing safeguarding all the related bonding linkages and components for long reliable service life. They are also installed at both ends of a circuit connected to terminations. At each point, electrically the internal design configuration and installed components are different serving a definite bonding purpose. The internal connections/links are of easily removable design, which can be easily removed; thus allowing disconnecting the individual cable sheaths for Sheath fault testing, establishing the integrity of sheath; that is no cracks/cuts or holes as a result of mishandling during cable laying.