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Classication and protective zones
Classication and protective zones
The requirements placed on surge protection and the
necessary tests for surge protection components are
stipulated by national and international standards. A product
can only be considered safe after the product has been fully
tested.
For rated voltages up to 1000 V AC, the standards are
valid for the manufacturers of surge protection
devices and the installers of the surge protection
within the facility or system. This catalogue contains
a list of valid standards for your reference.
The insulation coordination for electrical equipment in
low- voltage systems to IIIV EN 60664-1 (IEC 60664-1) is
critical for the design of a surge protection solution. This
species different dielectric strengths within electrical
systems. Based on this, individual lightning protection zones
can be set up according to IEC/EN 62305-3.
Lightning protection zones
A protective zone is characterised by a fully earthed
envelope. In other words, it has an enclosing shield which
enables full equipotential bonding. This shielding can be
formed by building materials such as metal facades or metal
reinforcements. Lines that pass through this shield must
be protected with arresters in such a way that a prescribed
protection level is achieved. Further protective zones can be
set up inside such a protective zone. Additional protective
zones that only have to be fused below the higher-level
protection zone’s insulation strength can be set up inside
such a protective zone.
This leads to a co-ordinated protection level for the objects
to be protected. Not every individual section has to be
protected with the maximum protection level (e.g. against
lightning). Instead, the individual protective zones guarantee
that a certain overvoltage level is not exceeded and hence
cannot inltrate that zone.
This leads to economic protection concepts with respect to
the capital outlay for protective components.
Classication
Originally, the arrestors were classied according to
coarse, medium and ne protection. These arrestors were
designated classes B, C and D in DIN VDE 0675 Part 6 / A1.
There was also a class A for external arresters (e.g. for low-
voltage overhead lines); however, this class has now been
abolished. IEC 61643-11 classies the protective zones as
Types I, II and III.
Comparison of surge protection classications.
Many national standards, e.g. in Austria, are derived
from the aforementioned VDE or IEC standards.
Formerly
DIN VDE 0675 Part 6 / A1
New
IEC 61 643-11
Arresters of requirements class B, lightning protection
equipotential bonding to DIN VDE 0185 part 1 (“B arresters”)
“Type I” arresters
Arresters of requirements class C, surge protection in permanent
installations, surge withstand voltage category (surge cat.) III
(“C arresters”)
“Type II” arresters
Arresters of requirements class D, surge protection in
mobile/permanent installations, surge withstand
voltage category (surge cat.) II (“D arresters”)
“Type III” arresters
At Weidmüller, we make sure that all our surge protection
products are tested by an independent testing lab for
compliance with the relevant product standards. This
is documented by test reports and corresponding test
certicates.
Lightning protection zone 0
A
Lightning protection zone 0
B
Protective zone 1Protective zone 2Protective zone 3
OPS 1OPS 2OPS 3
PAS
R
A
OPS: Overvoltage Protection System
W
The basics of lightning and surge protection
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