A shielded space or Faraday cage is designed to limit the influence of electromagnetic fields and radiation on a device or object. A shield is used to keep electromagnetic radiation out of a region. This technique provides protection for the specific equipment or people contained within the shield. The process uses a barrier made from conductive material arranged in a continuous configuration.
It is of little value to make a shield, no matter how well designed, and then to allow electromagnetic energy to enter (or exit) the enclosure by an alternative path such as cable penetrations or by having other electrical equipment such as video monitoring systems, lighting etc. which would reintroduce noise into the room introduces.
Cables will pick up noise on one side of the shield and conduct it to the other side, where it will be re-radiated. To maintain the integrity of the shielded enclosure, noise voltages should be filtered from all cables that penetrate the shield.
Electrical noise has many sources in modern offices from mains power frequencies of 60 or 50 Hz, to the noise from computer monitors, microphones, speakers, floor lamps etc. Oxford Faraday Cages can test your office or research space for sources of electrical noise and are able to recommend ways to minimize regular mains power noise; however under most circumstances a shielded space may be the only method to successfully reduce sources of electrical noise from an environment.