Hey guys and gals, I'm not an electrical-anything so please forgive my lay-person speak. I work in a lab. One of our rooms has a high magnetic field. It is causing interference with some analytical and computer equipment. Of course there is some health concern as well... Half of this room shares a wall (8-in concrete) with a Motor Control Center (Square D model 4) for our fume hoods, air handlers, compressors, what-not. It is clearly the source. I think the magnetic field is emanating from the solenoid relays... We use a cheapo EM meter (Trifield 100XE) to determine that the magnetic field is 100+ mGau at the wall and drops to @0 when I back up about 5 feet away from the wall. The field is only present on the half of the room that shares a wall with the MCC. Even if the meter isn't all that accurate it is clear that we can't put analytical equipment or people in that space (health effect studies are inconclusive - the worst kind for a management-type like me!). Cordoning that area and using it for storage would not be our first choice. Is there any way to shield against this in a cost effective way? Could the excessive field be caused by improper grounding or is it a necessary evil for MCC operation?