On the core breaking of flame retardant copper wire and cable

With the development of economy, the industry of wire and cable is also changing and developing. The application demand of wire and cable is also increasing. Meanwhile, the flame retardant and fire-resistant wires have emerged. How to detect the quality of these wires? So, let’s talk about the detection of the core breaking of flame retardant wires and cables!
1: The method of electrifying capacitance
Some aaac cable factories usually use capacitance comparison to find out the approximate position of broken wires. The efficiency of the method is very low, which is to use continuous power on to accurately break the cable. Generally, it takes about 1 and a half hours to find a broken line point. This method is very unlikely to find the broken core for the flame retardant cable which has been completed in the shielding, armouring and sheath process. If it is not made properly, the flame retardant cable will be discarded. This method is basically no longer used.

2: The capacitance method and the induction method are combined
This method is used for core breaking, which requires that there is no metal layer and no extrusion cover outside the core. In the search, we first find out the approximate position of cable break with capacitance, and then use inductive voltage method to find the broken point accurately. This method is very simple and fast, and it is also the most used method at present. The induction voltage method is to connect 650V AC voltage at one end of the broken core of the cable, and the other end and other cores to ground, and then test with an inductive pen which can send light signal. When the probe slips out of the core, the signal will change, so that the cable break point can be accurately found.

3: Combination of constant current source and bridge method
This method is used for completed cables or cores covered with metal layers. The method of finding is to burn and break down the insulation at the broken core of flame retardant cable with constant current source, and then to locate the fault point accurately by bridge fault location instrument, which is also a common method.