Surge Protection For Power Supply (old)

TN-C (N and GND are bonded)
 
Nominal voltage U   60 V AC    120/208 V AC    240/415 V AC    400/690 V AC    554/960 V AC
 
 
TN-S (N and GND are Separated) 
 
Nominal voltage UN   24 V AC    230 V AC    240 V AC    230/400 V AC     240/415 V AC