Hardware Installation and Reference Guide    Appendix 
84 
7.4  Lightening Protection 
Installing AC Power Arrester (Lightning Protection Power Strip) 
The AC power port must be connected to an external lightning protection power strip to prevent the switch from being struck by 
lightning when the AC power cord is introduced from the outdoor and directly connected to the power port of the switch. The lightning 
protection power strip can be fixed on the rack, workbench, or wall in the equipment room by using cable ties and screws. AC power 
enters the lightening protection power strip and then gets to the switch. 
Figure 7-4 Power Arrester 
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.
Normally running indicator: When the 
indicator is green, the circuit is working 
properly. Otherwise, the protective circuit is 
damaged.
Installed electronic circuit board
Multi-purpose sockets (connected to the power 
supply of the switch)
Overload auto-protector, which 
can be reset manually
IEC standard socket, which is 
connected to the power supply 
in the equipment room through 
the power cable
Power switch
 
 
The power arrester is not delivered with the switch. Please purchase it based on actual requirements. 
 
Make sure that the PE terminal of the power arrester is well grounded. 
 
After the AC power plug of the switch is connected to the socket of the power arrester (lightning protection power strip), the 
lightning protection function is implemented only if the RUN indicator is green and the ALARM indicator is OFF. 
 
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 has not 
been grounded. 
Installing the Ethernet Port Arrester 
Please connect an Ethernet port arrester to the switch to prevent the damage by lightning before connecting an outdoor Ethernet 
cable to the switch.