Surge Damage Prevention Measures
Equipotential bonding is performed
Among the measures to prevent damage from surges, the first priority is to maintain equipotential during a surge (transient) state. Common grounding and equipotential bonding are implemented as a means to maintain equipotential when a surge is introduced due to lightning or power system switching.
At this time, the device used for equipotential bonding is a surge suppressor (SPD; Surge Protective Device).
When multiple lines (such as power lines and communication lines) are connected to one device, a surge suppressor is installed for each line, and the ground terminal of each surge suppressor and the ground terminal of the device are connected to an equipotential bonding bar to ensure that the equipotential is maintained between each line and device during transient conditions.
Another thing to keep in mind is that when connecting devices to be protected, the area of the conductors to be connected should be narrow. This is because when lightning current flows into the ground through the down-conductor of the lightning protection equipment, a strong magnetic field can be formed inside the building, and at this time, a voltage proportional to the cross-sectional area of the conductor in the magnetic field can be induced in the conductor.
