Appendix 1. EMC Installation Guidelines
1.6 EMC Countermeasure Parts
164
Example of surge absorber installation
From
power supply
200VAC
/230VAC
input
Panel
leakage
breaker
Transformer
Circuit breaker
NC control
section
Other devices
(panel power
supply, etc.)
Circuit
breaker
Reactor
NC drive
section
Circuit protector
Surge absorber (a)
Control panel
(relay panel,
etc.)
Ground
Grounding plate
Other devices
(panel power
supply, etc.)
Surge absorber (b)
MC
A
B
C
Example of surge absorber installation
Precautions
(1) Use a thick wire that is as short as possible to increase the lightning surge absorbing effect as shown
with the bold lines in the installation example above.
Wire material : Diameter 2mm
2
or more
Wire length
Length of wire connected to surge absorber (a) : A is 2m or less
Length of wire connected to surge absorber (b) : B is 2m or less
Length of wire connected to surge absorber (b) : C is 2m or less
(2) When carrying out the insulation withstand voltage test on the power supply line, the surge absorber will
activate by the applied voltage, so always remove surge absorber (b).
(3) If a surge exceeding the tolerance is applied on the surge absorber, a short-circuit fault will occur. Thus,
always insert a circuit protector to protect the power supply line.
Normally, current is not passed to the surge absorber (a) and (b), so the circuit protector can be used for
the other devices.