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Practical Inspection of Wires and Cables

As people's demand for cables continues to increase, the cable industry is also developing rapidly. The market is flooded with all kinds of cables, and there are many counterfeit cables. It is necessary for the buyer to carefully identify and purchase high quality cables that meet the specifications. So how do we tell which are good cables that meet the specifications and which are counterfeit? Here are some practical ways to detect cables.



External Inspection


The external inspection of the cable is mainly the inspection of the appearance, size and structure of the cable (estructura de cable). First of all, the appearance, when we see the cable, we should first observe whether the surface of the cable is neat and smooth, and whether there are obvious cracks, spots and problems that affect our normal use in the future. If necessary, we can conduct some small tests to determine whether the cable meets the specifications of corrosion resistance and oxidation resistance. Secondly, the detection of the size of the cable, we can check the size specifications of the cable marked on the outside of the cable, so as to detect whether the size of the cable is in line with the specifications.


Internal safety inspection


The safety of the use of cables is crucial. In life, there are numerous news of accidents occurring because of the use of cables that do not meet the specifications. So we should test the safety of cables before use to avoid similar tragedies again as far as possible. For the internal safety testing of the cable, the methods generally used are DC resistance testing and insulation resistance testing.


1. DC resistance test


The purpose of DC resistance testing is to test whether the cable is a qualified product in accordance with national regulations by testing the electrical conductivity of the cable. If the value obtained after the test is less than the national standard value, then such a cable is a qualified product, and vice versa is not qualified products.


2. Insulation resistance test


Insulation resistance test is generally used is the voltage and current method, this method and DC resistance test looks similar in principle, in fact, in essence, there is still a big difference, insulation resistance test method is also called the high resistance meter method. Is by testing the cable's metal protective sheath for the current shielding ability of the high and low to determine whether the cable is in line with national norms of the product.


The voltage and current method is generally used in the insulation resistance. This method seems to be similar to DC resistance test in principle, but in fact, it is very different in nature. Insulation resistance test method is also called high resistance meter method. It determines if the cable is a product that meets national specifications by testing the metal protective sheath's (armadura metal de cable) ability to shield against current.