Page 3
Symbol
Meaning
CAT III
IEC Overvoltage Category III
CAT III equipment is designed to protect against
transients in equipment in fixedequipment installations,
such as distribution panels, feeders and short branch
circuits, and lighting systems in large buildings.
CAT IV
IEC Overvoltage Category IV
CAT IV equipment is designed to protect against
transients from the primary supply level, such as an
electricity meter or an overhead or underground utility
service.
THE METER
METER STRUCTURE
1
2
3
4
5
6
7
8
10
11
9
