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Yellow/Line SPD Classes – Symbols
All SPD types of the Yellow/Line family for use in information technology systems are assigned a Yellow/Line SPD class and marked with a symbol in
the technical data sheet and on their rating plates. The symbol for the Yellow/Line SPD class graphically combines 3 important characteristics of the
SPD and can be one single symbol or a combination of individual symbols:
Characteristics Single symbol Definition
Discharge capacity of an SPD
(according to categories from
IEC 61643-21 / EN 61643-21)
Protective effect of an SPD
(limitation below the test levels
according to EN 61000-4-5)
A
B
C
D
Impulse D1 (10/350 μs), lightning impulse current ≥ 2.5 kA/line or ≥ 5 kA/total
• exceeds the discharge capacity of B – D
Impulse C2 (8/20 μs), increased impulse load ≥ 2.5 kA/line or ≥ 5 kA/total
• exceeds the discharge capacity of C – D
Impulse C1 (8/20 μs), impulse load ≥ 0.25 kA/line or ≥ 0.5 kA/total
• exceeds the discharge capacity of D
Load < C
Required test level of the terminal device: 1 or higher
Required test level of the terminal device: 2 or higher
Required test level of the terminal device: 3 or higher
Energy coordination
(with another Yellow/Line SPD)
k
Required test level of the terminal device: 4
SPD with decoupling impedance, suitable
for coordination with an SPD marked
SPD is suitable for coordination with an SPD
with decoupling impedance k
Examples of energy coordination of SPDs according to Yellow/Line SPD classes:
Use of a combined lightning current and surge arrester
lightning current
immunity
test level
acc. to EN 61000-4-5
M
terminal
device
1
Cascaded use of SPDs
lightning current
surge
immunity
test level
acc. to EN 61000-4-5
G
O
terminal
device
1
Energy coordination of Yellow/Line SPDs
is independent from the conductor length
GO
discharge capacity
G
O
SPD suitable for coordination
with another SPD ( )
decoupling for coordination
with another SPD ( )
specific protection of
terminal equipment
EN 61000-4-5
178 www.dehn.de