Datasheet

II-2015, www.findernet.com
25
E
7P
SERIES
7P SERIES
Surge Protection Device (SPD)
Short-circuit protection for the SPD is provided by the overcurrent
protective devices (fuses type gL/gG) recomended.
If the overcurrent protective devices F1 (which are part of the installation)
have a rating smaller than or equal to the maximum recommended rating
for the overcurrent protective devices for the SPD, then F2 (back up fuse),
can be omitted.
7P.0X:
IfF1>250A, then F2=250A
IfF1<=250A, F2 can be omitted
7P.1X, 7P.2X:
IfF1>160A, then F2=160A
IfF1<=160A, F2 can be omitted
Coordination of SPD
Optimal protection from surges requires cascaded coordinated SPDs.
Coordination has the purpose of splitting the energy associated with
voltage across the SPDs and it is achieved by introducing an impedance
between the SPDs, or alternatively, by connecting them using wires having
the minimum length indicated in the figures below, in order to use the
cable's own impedance.
V-shape connection
Using a V-shaped connection eliminates transferring downstream the
inductive voltage generated by the surge current in the connecting wire
to the SPD. This increases the protection to the system and equipment
downstream. A limitation of this connection is that the nominal current for
the downstream system is limited to 125A, which is the maximum current
permitted through the double SPD terminals.
125 A
125 A
125 A
For systems where the rated current is greater than 125A, it is necessary to
connect the SPD in parallel with the equipment (E/I).
Connecting cable
Depending on the type of connection, serial (V-shape) or parallel (T-shape),
ensure that both the maximum cable lengths and minimum cross section
of the connecting wires are respected in accordance with the information
below (IEC60634-5-534):
The section of the connecting wires (copper) must not be less than:
SPD Type 1: 16 mm
2
if it is subject to discharge a significant lightning
current, 6mm
2
otherwise
SPD Type 2: 6mm
2
SPD Type 3: 1.5mm
2