Ferrous and Non-Ferrous Materials

All the high voltage switchgears bottom cable entry plate includuing transformer primary and secondary bottom cable entry plate, has to be non ferrous material as to eliminate the induction of the magnetic field by the power cables. Commonly, most of the cable used for the high voltage switchgears is by single core cables.

If the bottom plate of the cable entry is made from ferrous material, Ferromagnetism action on the ferrous materials will occur. Cable that carried an electric current produces a magnetic field. The magnetic field a pattern of circular field lines surrounding the wire. When Ferromagnetism occurs at the bottom entry plate, there will be some heat generated and in some cases the bottom entry plate can vibrate.

Even Aluminum is a good conductive material, just like the copper, but both of these material is non ferrous material and both of them does not induce ferromagnetism. Likewise, other material such as stainless steel, alloy and brass.