Brochure/Catalogue

TOV error mode TOV = arresters must be able to withstand persistent voltage increases with
mains frequency, so-called “temporary overvoltages” or “TOVs”. Various error
states inside and outside the low voltage consumer facility of a building can
occur to cause TOVs. An example of one of the causes of TOVs described in
VDE 0100, part 442, is an earth fault on the high voltage side of the local grid
transformer.
Failure mode
Mode1: Surge protection has switched itself off, no protection is being provided.
Mode2: Surge protection has short circuited with an internal connection, the
terminal equipment is protected by the short. The supply or the signal is
no longer operational.
Transverse voltage Interference voltage between two conductors in circuit.
Triggered sparkover gap A gas-lled sparkover gap which is ignited by a capacitive voltage divider with a
pre-set voltage value.
TT power grid Power system with 4 wires; 3-phase conductors and the neutral conductor come
into the building. The building's PE is not connected to the power grid.
Type I For the purpose of lightning protection equipotential bonding according to
IEC 37A/44/CDV; also refer to requirement class B.
Type II For the purpose of surge protection in the xed facility, preferably for use in
impulse withstand voltage category III, also see requirements class B.
Type III For the purpose of surge protection in the xed facility, preferably for use in
impulse withstand voltage category II, also see requirements class B.
Varistor Voltage-dependent metal oxide resistor; the resistance decreases with increasing
voltage.
Glossary
W
The basics of lightning and surge protection
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