Brochure/Catalogue

Fuse, back-up fuse A back-up fuse is required if the upstream fuse F1 is greater than the maximum
value specied by the manufacturer. Remember to select the largest nominal
value in keeping with the ratio F1 to F2 (back-up fuse before SPD) = 1 : 1.6.
Be sure to take the triggering characteristics into account if a circuit breaker is
being used in the surge protection equipment instead of the fuse specied in the
installation instructions.
Galvanic coupling The interference circuit and the useful circuit have a common impedance.
Gas discharge tube Voltage-dependent, encapsulated switch with high current-carrying capacity.
HAK House junction box.
I&C Measurement and control systems.
IMAX Maximum current that can be switched by an arrester.
Inductive coupling Coupling from two or more current-carrying conductor loops.
Insertion loss (attenuation) Attenuation in decibels that is added by inserting a four-pole.
INSTA Installation housing in accordance with DIN 43880, suitable for installation in
distribution boards.
Insulation co-ordination or rated
impulse withstand voltage
Standing surge current strength of the insulation in parts of the facility, according
to DIN VDE 0110 T.1.
Internal lightning protection Internal lightning protection refers to protecting electrical equipment from power
surges.
Intrinsically safe circuit Intrinsically safe circuits are especially vulnerable because even a small amount
of energy is sufcient to nullify their intrinsic safety. During the installation of
intrinsically safe circuits (including cables and wires), be sure that you do not
exceed the maximum allowable inductance, capacitance, or the L/R ratio and the
surface temperature.
I
L
Maximum nominal current via the internal cross-connection of an arrester with
two connections for one phase.
Ipeak = I
imp
Current peak value of a test pulse.
I
sn
Peak value of the nominal discharge current.
IT power network Power system with three phase conductors, constructed with insulation to the
earth potential. The building's PE is not connected to the power grid.
Leakage current Current that ows to PE at nominal voltage.
LEMP Lightning electromagnetic pulse = electromagnetic interference pulse.
Lightning protection equipotential
bonding
Equipotential bonding of separated metal parts with the LPS using a direct
connection or connection via surge protection devices in order to reduce the
lightning current caused by the potential difference.
Lightning pulse current I
imp
Dened by the peak value Ipeak and the charge Q, when tested in accordance
with Type I with 10/350 µs pulse.
Limiting frequency Species the max. frequency at which a transfer will function. At higher
frequencies, the protective circuit cushions so strongly that no transfer is possible.
Longitudinal voltage Interference voltage between the active conductor and the earth.
Glossary
W
The basics of lightning and surge protection
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