Although magnetic NDT of wire ropes has been in regular use in a number of countries for 30 or more years, it is still not a commonly known NDT method. This method is well known and recognised in application areas such as inspection of hoisting ropes in deep mines and inspection of ropeways.

The permanent magnets have been used to longitudinally magnetise a length of rope as it passes through the head. A constant magnetic flux that magnetises the rope must be strong enough to create condition near magnetic saturation of the rope length. The amount of saturation is measured and any changes due to loss of material or breaking can be detected.