GreenLED

I'm also in need of something that contains a magnetic field. However, I'd like to actually force the magnetic field to stay inside the "box" without saturating the outside whatsoever. It sounds like from the discussion that's gone on this is not possible as the field will eventually break through the shield. If a "break through" is inevitible, then I'd like to use a layering method to simply dissipate the field so as to create a shield that will last for a long period of time. This magnetic field by the way will be moving. Therefore, let me know of other considerations that I need to keep in mind. Cost is (not at the moment) the bigger issue here, it's the goal that needs to be met. The goal is either containing the magnetic field with no saturation -- or for a long period of time, we're talking 10 - 20 years or the dissipation of the magnetic field with the same second objective -- no "break through". Also, can someone explain what you're referring to as far as "grounding" the magnetic field goes. Since this magnet will be in motion, does this pose a electrical hazard that warrants the need to "ground" the device?