Specifications

35
Din Rail Low Voltage Surge Protectors
Choosing Surge Protectors
CITEL’s line of AC power surge protectors is designed to
cover all possible configurations in low voltage installations.
They are available in many versions, which differ in :
- Type or test class (1, 2 or 3)
- Operating voltage (Uc)
- AC network configuration (Single/3-Phase)
- Discharge currents (Iimp, Imax, In)
- Protection level (Up)
- Protection technology (varistors, gas tube-varistor, filter)
- Features (redundancy, differential mode, plug-in, remote
signaling...).
The surge protection selection must be done following the
local electrical code requirements (i.e. : minimum rating for
In) and specific conditions (i.e. : high lightning density).
●
Choosing the Type of surge protectors
This choice is in relation to the LPS condition (Lightning Protection
System) and the SPD location in the installation.
●
Choosing of the operating voltage Uc
The SPD Uc voltage (maximum continuous operating voltage)
depends on:
- Nominal voltage of the AC network (Uo)
- Level of possible temporary overvoltages (TOV) U
T
- Type of AC system (TN, TT, IT).
●
Operating voltage Uc (Line/Ground)
●
AC network configuration
DS surge protectors are available for single, 3-Phase and 3-
Phase + neutral AC networks.
●
Choosing Iimp
The impulse current Iimp is defined for Type 1 SPD. The
minimum rating for Iimp is 12.5 kA by pole, following IEC
60364-5-534. This level is adapted to the real phenomenon.
CITEL proposes, in its Type 1 SPD range, 2 levels of Iimp
current : 15 and 25 kA.
●
Choosing In and Imax currents
The relevant nominal discharge current In for the SPD is in
relation with the lightning risk in the installation area.
The minimum rating of In for a SPD connected at the installation
entrance is 5 kA (8/20
㎲
waveform), required by standard.
Nevertheless higher ratings are advised in case of high
lightning density. Moreover higher values of In current will
increase the SPD lifetime.
Imax (max. discharge current) rating is linked to In.
●
Choosing the protection level Up
The user must select a surge protector with a protection level
Up adapted to the withstand level of terminal equipment. In
every case, the lower the protection level Up, the better the
protection.
IEC 60364 standard calls for the minimum protection level of
2.5 kV for a SPD connected at the entrance of a 230/400 V
network : this level is in compliance with the withstand of
robust devices (electromechanical type).
Electronic-based terminals have lower impulse withstand and
require a better protection : so, surge protectors with 1.5 kV
protection are necessary to provide efficient protection.
A relevant choice of the SPD technology, as well as the use of
coordination diagram can help to improve the protection level.
Configuration SPD Location CITEL
Installation equipped Type 1 Origin of the DS150
with LPS or could be hit installation origin DS250
by lightning (Panel or main DUT250VG
switchboard)
Installation without LPS Type 2 main switchboard
DS70R, DS40
DU40, DUT40
Secondary protection Type 2 close to protected DS10
(downstream primary SPD) (or Type 3) equipment DS210D
DUT10
AC Network 230/400V 120/208V
AC system TT TN IT TN
Voltage Uc 255 V 255 V 400 V 150 V
Voltage U
T 400 V 335 V - -
Example of DS42-400 DS42-320 or DS42-400 DS42-120
CITEL product DS42-400
Configuration Iimp CITEL
Very high lightning density 25 kA DS250E
Bad earthing DS250VG
DUT250VG
High, meduim or low lightning 15 kA DS150E
density DS150VG
Conditions In CITEL
Very high lightning density > 20 kA DS70R
High or medium lightning density 10-20 kA DS40
DS240
Low lightning density 5 kA DS10
or secondary SPD DS210D
Conditions Recommended Up
SPD at the installation entrance 2,5 kV maximum
Electromechanical protected equipment 2,5 kV
Electronic-based protected equipment 1,5 kV