Magnetic shielding locations and requirements
When a building contains electrical and electronic systems that require protection against lightning electromagnetic pulses, the location and requirements for magnetic shielding should comply with the following regulations.
1 The building’s roof metal surface, facade metal surface, concrete inner steel bars, metal door and window frames and other large-sized metal parts (except for the first type of lightning protection buildings using independent air terminals and grounding devices) should be connected together at equal potentials, And connected with lightning protection device.
2. Metal shielding layer of shielded cables. The shielding layers of shielded cables should be at least at both ends, and equipotential connections should be made at the junction of lightning protection zones. When the system requires equipotential connections only at one end, two layers of shielding or steel pipe laying should be used. , the outer shielding or steel pipe should be at least at both ends, and equipotential connections should be made at the junction of lightning protection zones.
3. Penetrate the conductive metal object into the grid-shaped large space shield of the building or room made up of natural components such as metal objects, metal frames or reinforced concrete steel bars, and make an equipotential connection with the nearest grid-shaped large space shield.
4. The shielding shell, shielding door, various filters, cut-off ventilation guide windows, shielding glass windows, and shielding black boxes of the special shielding room for lightning protection should comply with the requirements of the engineering design documents and be connected together at equal potentials.
5. For connecting lines between separate buildings, if there is no shielding layer, the lines should be laid in metal pipes, metal gratings or concrete pipes with steel bars in the shape of a grid. The metal pipes, metal gratings or steel bar gratings should be laid from one end to the other. The other end should be conductive and connected to the equipotential bonding tape of the building at both ends; if there is a shielding layer, both ends of the shielding layer should be connected to the equipotential bonding tape of the building.
