Guide to the Wiring Regulations
Magnetic Flux
Eddy Current Flow
Current Flow
Current Flow
Figure D 5.3  Eddy current in a metallic gland plate.
Figure D 5.3 shows how and where eddy currents are created at a metallic gland plate. Eddy currents can overheat iron or steel cabinets, locknuts or bushings or any ferrous metal that completely encircles the single-conductor cables. This presents no problem in multi-Âconductor cables, where the magnetic fields tend to cancel each other out. For single-core cables, it is recommended that these cables enter metal enclosures through a non-ferrous plate (e.g. aluminium). Any connectors, glands and similar that completely surround the conductors must be of nonferrous materials. Slotting the equipment enclosure between the cable openings was considered an acceptable way to reduce the effects of eddy currents, but is no longer common practice (some feel that the practice of slotting weakens equipment).
D 5.3
Electrical connections and joints D 5.3.1 General A typical installation comprises a multitude of joints and connections, both in conductors and in wiring containment systems. As is seen from reading other chapters of this book, the soundness of connections is crucial, and loose or
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