Due to different modes and operating conditions of cable joints, different technical levels of construction personnel and uneven quality of cable accessories, the reasons for cross-linked cable joint failures also vary. Failures of cross-linked cable joints are mainly concentrated in two areas.

1. Poor workmanship in making cable splices.

(1) Connecting metal tool contact surface is not handled well. Due to the production or storage conditions, there are impurities on the terminals or the wall of the connecting tube, burrs and oxide layer. The impact of conductor connection quality is quite serious. Especially the surface of aluminum is very easy to produce hard and insulating alumina film layer. Therefore, the connection process of aluminum conductors is much more rigorous than that of copper conductors.

(2) Damage to conductors. The cross-linked insulating layer is tougher and more difficult to peel and cut. Construction personnel ring cut with an electrician's knife left scratch right cutting, sometimes simply use a ring saw cut deep marks, often poor grip and make the conductor damage.

(3) The conductor wire is not laid well. Conductor connection when the insulation stripping length required to crimp the gold hole depth more 5mm, but because the product hole depth is not standard, easy to cause the stripping length is not enough or because of crimping when the string position so that the wire end of the formation of voids, resulting in increased contact resistance, increased heat generation.

2. Insufficient pressure.

(1) Crimping machine pressure is not enough. Crimping machine production plant more, but there is no uniform standard, some mechanical pressure pliers narrow pit and crimping in place after the upper and lower pressure die does not match.

(2) Has large gaps in the connection fittings. Most cross-linked cable splices use connecting fittings or oil paper cable by producing fan-shaped cable lugs and pressure tubes. In theory, the effective cross-section of round and fan-shaped wire cores is the same, but by the actual operation of the two the crimping effect is very different. Since the conductors of cross-linked wires are tightly stranded round cores, with the commonly used inner diameter of the metal tool has a large gap, crimp does not achieve sufficient compressive strength. The contact resistance is inversely proportional to the applied pressure, so the resistance increases. Insufficient cross-section of the connection fitting is a very important reason for heating of cross-linked cable joints.