H3C S5120-EI Series Installation Manual page 86

Make sure that the arrester is well grounded before using the lightning arrester for power.
After inserting AC power cord plug of switch into the socket of lightning arrester, if the green LED is
on and the red LED does not alarm, it means that the lightning arrester of power is running and the
function of lightning protection has taken effect.
Pay adequate attention if the red LED is on. You should correctly locate the problem, whether it is
caused because the ground wire of the arrester is not well grounded or because the live and zero
wires are connected in reverse direction. You may check that in the following way. When the red
LED is on, use a multimeter to examine polarity at the power socket of the arrester. If it is same to
that of the power socket in the equipment room, it means that arrester is not well grounded. If it is
adverse to that of the power socket in the equipment room, it means that the power socket of the
arrester is set to the reverse polarity. In this case, you should open the power socket of arrester to
correct polarity. After that, if the red LED still alarms, it means that the arrester is not well grounded
yet.
A-2