Entry of single core cable from roof

[RAgrawal]

As all of us know that there should not be a ring of megnetic material surrounding single core cable.

My doubt is, if single core cable is passing through RCC roof, then it will be sourrounded by steel structure burried in cement and there maay be heating in steel structure due to eddy current caused by megneetic ffieeld produced by current is ssingle core cables. Is this statement true? if yes then whats the remedy of it?

 

[tulum]

Not sure what RCC roof is....

What is the current? In Canada the CEC 12-106(5) requires that 1/c cables carrying more than 200A not be sounded by a ferrous material.

If it is over 200A; 12-3024(7) lists the precautions to take:

"Precautions to be taken to prevent overheating of the metal by induction shall include the use of non-ferrous or nonmetallic box connectors, locknuts, and bushings and if the non-ferrous metal plates or insulating plates are field installed they shall be at least 6mm thick.... "

Cutting a slot in the metal plate used to ba an acceptable practice to stop the path of eddy currents, but is now being shyed away from.


Regards,
TULUM