Electromagnet field,can it penetrate concrete wall?

Question

hello 2ALL. If i attach to wall a - 1)220volt AC,or 2)12volt DC current pass through a electromagnet,can it penetrate the concrete wall.if it possible, what is the wall thickness in inches.

Answer 1

It is all about the magnetic permeability of the medium.  Concrete will allow a magnetic field to pass thru but, if the concrete has steel rebar or steel reinforcing wire mesh, the steel will interfere with the magnetic field.  You can find values for magentic permeability for different materails in, for example, the Handbook of Chemistry and Physics (not sure if they have the value for concrete).   good luck

Answer 2

If you have a flat coil with a radius of 3 feet, then 3 feet from the center the magnetic field is about half as strong as it was at the center. The rebar in the concrete wall will reduce this a little, but basically the field can penetrate the wall without any problem. AC will get attenuated a bit more than DC, and high frequencies would be severely attenuated. The magnetic field gets attenuated as 1/r^2, where r is the distance from the WIRE (not the center of the coil) to the point of measurement.

Answer 3

Why do you want to know?

Please elaborate