Surge protector wiring diagram - surge protector access mode
In the TN standard, general SPD only for common mode connection, which is connected to the neutral line and ground line between.
But in the initial position of the TN-S system, access the surge protection device is not needed between the neutral wire and ground protection. Only the power port for particularly important equipment third class a lightning protection level in third, grade four and grade B in the lightning protection level, only need to do differential access, which increase the surge protector is connected between the phase line and the neutral line.
In the TT standard, when the first surge protector in leakage protection device, can be used as the common mode connection. When the leakage protector is located on the first level and the high voltage surge protection device, system as the center point of the grounding system, surge protector should be "3 + 1" connection, namely the three phase of the neutral line are respectively connected with a surge protector, neutral line on the ground is connected with a surge protector.
In the IT standard, surge protector only for common mode connection.
（The installation of SPD in the IT system without neutral line）
1, the power of the device.
2, power distribution panel.
3, total ground terminal or rod.
4, surge protector.
5, SPD grounding, 5A or 5B.
6, protected equipment.
7, residual current protection device (RCD).
SPD - F manufacturing plant requirements for the installation of protective devices (e.g., fuses, circuit breakers, RCD);
RA - the ground electrode of the device;
RZ - earth electrode of power supply system;
(open or /----).
（Industrial installation circuit）
B2, B1 - Building 1, 2.
MB - main building.
EB - equal potential wiring board.
MPB - the main switchboard.
Eq - load equipment.
PB - distribution panel.