Cables are meant to carry electric current safely and efficiently. However, these safety and performance goals can be compromised if a counterfeit cable is produced. The counterfeit cable may result in performance issues such as poor lifespan or even safety concerns such as overheating and increased risk of electrical shock or fire.
Counterfeit or fake cables are, by definition, falsely claiming that they comply with safety and performance standards when they do not. This may include marking on the label that they are produced to specific international or national standards even though they do not fulfil them.
We have deconstructed the two basic components that determine the quality of the cable:
The copper amount is inadequate.
The most apparent method to decrease the cost of producing a cable is by reducing the amount of the largest cost component, which is the copper conductor.
This can be accomplished by either undersizing the cross-sectional area (“CSA”) of the copper conductor or by using impure copper.
Under sizing, the CSA of the copper conductor can be accomplished by reducing the number of strands or by lowering the individual diameter in the conductor. Impure copper means using less than 99.9% copper content, or other material, like copper alloy or even copper-plated aluminium. Either method will increase the cable’s conductor resistance above the maximum value specified in the relevant standard.
Conductors with higher resistance may pose a safety threat. The inherent resistance causes a larger heating effect when current passes through a conductor. Also, the conductor's heat may cause premature insulation failure, which may result in a short circuit or even an electrical fire.
Conductor resistance tests can measure the adequacy of the CSA of copper conductors in a cable. Voltage is applied across a sample cable length, and the current across the sample is measured. Using Ohm’s law, the resistance of the sample can be calculated. If the measured resistance is higher than the specified maximum value, the CSA of the copper conductor is inadequate.
Low-grade material compound
Much like the conductor, substandard cables can result from a reduction in the quantity and quality of insulation material used. Less quality insulation can result in lower rated voltage. Cheaper cables also may have worse additives added to the insulation and/or sheath material. This may result in decreased cable flexibility, decreased insulation resistance, and increased susceptibility to cracking of the insulation or sheath with age.
There are many material properties that are important to try. Here we highlight two important types to know as an introduction.
The insulation resistance test measures the current leakage from the cable, verifying that the conductor is sufficiently insulated from the environment. Poor insulation may result in short circuits, electric shock, or fire. Usually, this test is carried out at the maximum conductor temperature under normal operations. The material type used in insulation and/or sheathing determines this maximum operating temperature. The higher the insulation resistance, the better the cable is well insulated from the environment.
Tensile strength and elongation tests measure the mechanical properties of the insulating and sheathing compound. A material's tensile strength is the force needed to pull that material to the point of breaking. Elongation is a measure of the length that the material can be stretched to before breaking.
The cable material is tested at two-time points. Once after the manufacturing of the cable and the other after accelerated ageing by subjecting the material according to a specified temperature and duration. The tensile strength and elongation tests are repeated after ageing to show how ageing affects the mechanical properties of the materials.
Due to the larger variety of potential insulation and sheath issues, more tests are required to ensure quality. We have described a small set of basic but important tests conducted on all types of cables, but additional tests are required to provide other claimed material properties are fulfilled. These include tests of the cable’s fire resistance, water resistance, behaviour under thermal stress, and flexibility.
In summary, counterfeit cables claim to comply with international or national standards but skimp on either CSA of copper or the quality of insulation and/or sheath materials. However, there is no direct way to identify a counterfeit cable as it requires a complete set of lab tests, and therefore it is important to trust the brand of the cable you are purchasing. Buying from a reputable cable brand with products certified by a third party will ensure the longevity and safety of the product down the road, as you will not have to worry about replacing it sooner than the shelf life.