### 6.3.1 Installing an AC Power Arrester (Lightning Resistance Socket)

When an AC power cord is introduced from outdoors and directly connected to the power port of the switch, the AC power port must be connected to an external lightning protection power strip to protect the switch against lightning strokes. The lightning resistance socket can be fixed on the rack, workbench, or wall in the machine room by using cable ties and screws. AC power enters the lightning protection power strip and then enters the switch.

Figure6-4 Power Arrester

No. | Description
1 | Installed electronic circuit board
2 | Normally running indicator: When the indicator is green, the circuit is working properly. Otherwise, the protective circuit is damaged.
3 | Grounding and polarity detection indicator: If the indicator is red, cable connection is incorrect (the ground cable is not connected, or the N and L lines are reversely connected). Check your power supply line.
4 | Power switch
5 | IEC standard socket, which is connected to the power supply in the equipment room through the power cable
6 | Overload auto-protector, which can be reset manually
7 | Multi-purpose sockets (connected to the power supply of the switch)

Note

​The power arrester is not delivered with the switch. Please purchase it based on actual requirements.

Important points

l Make sure that the PE terminal of the power arrester is well grounded.

l After the AC power plug of the switch is connected to the socket of the power arrester (lightning resistance socket), the lightning protection function is implemented only if the RUN indicator is green and the ALARM indicator is OFF.

l If the ALARM indicator on the power arrester is red, check whether it is caused by poor grounding connection or by the reversed connection of the Null and Live lines. The detection method is as follows: Use a multimeter to measure the polarity of the power socket for the arrester when the indicator is red. If the N line is on the left and the L line is on the right (facing the socket), the arrester's PE terminal is not grounded. If not, the polarity of the arrester power cord should be reversed. In this case, you should open the power arrester and rectify the polarity of the connection. If the indicator is still red, the arrester's PE terminal is not grounded.