Specifications

46
RF SOLUTION-CITEL
󳀏International:
-
IEC 61643-21 : Tests of surge protectors for communication
lines.
- IEC 61643-22 : Choice/installation of surge protectors for
communication lines.
󳀏France:
-
NF EN 61643-21 : Tests of surge protectors for communication
lines
- Guide UTE C 15-443 : Choice/installation of surge protectors
Use of surge protectors
In case of lack of recommendations or standard
requirements, the decision of using surge protectors on
telecom and datalines could be taken by following :
- the requirements of the terminal equipment manufacturer.
- a curative action following equipment failure.
- a risk analysis.
●
Risk analysis
In order to assess quickly the probability of the lightning
surges and theirs consequences, a simplified risk analysis
could be performed following the table below.
The level of recommendation (from << no recommendation >>
to << highly recommended >> ) of using surge protectors
increase with the number of parameters classified as
<< high
risk
>> on the table.
A more detailed risk analysis is available on the IEC 61643-
22 standard.
Surge Protection parameters
In choosing surge protection for your installation, bear the
following in mind :
󳀏The type of line :
- There is an appropriate level of protection and protection
diagram for each type of line.
󳀏The site configuration :
- Number of lines to be protected.
󳀏The requested type of installation :
The CITEL line provides the following possibilities :
- Installation in wall-mounted box, plug mounting, on
distribution frame
- various types of connection (wrapping, IDC, screw
terminals...)
󳀏Features
Some surge protectors are equipped with pluggable modules
(E280, DL..)
Installation
To be effective, surge protectors must be installed in
accordance with the following principles :
󳀏The earth point of the surge protector and of the protected
equipment must be interconnected.
󳀏
The protection is installed on the network entrance, to divert
impulse currents as fast as possible.
󳀏The protected equipment must be nearby (protector/
equipment distance less than 30m long). If this rule cannot
be followed,
<< secondary >> protection must be installed
near the equipment (coordinated surge protection).
󳀏The grounding conductor (between the earth output of the
protector and the installation bonding circuit) must be as
short as possible (less than 0.50 m) and have a cross-
sectional area of at least 2.5 mm
2
.
󳀏The earth resistance must comply with the standards in
force (no special earthing requested).
󳀏Protected and unprotected cables must be kept well apart
to limit coupling.
Maintenance
CITEL dataline surge protectors require no maintenance or
replacement. They are designed to withstand repeated and
heavy impulse currents without damage.
Nevertheless a controlled fail-safe mode (short circuit to
earth) is planned in case of surges exceeding the parameters
of the surge protectors:
Protective short-circuit occurs in the following cases :
-
sustained contact between the telecom line and a power line .
- exceptionally heavy lightning impulse current.
In these rare cases, the surge protectors will go definitively in
short-circuit. By this way, it protects the terminal equipment
and warns about its failure.
To re-active the line, the surge protector must be replace.
The basic parameters of the surge protector for datalines
could be controlled with dedicated testers (CITEL SPT1002).
Parameters Low Risk High Risk
Lightning density (Ng) < 2,5 > 2,5
Site configuration Single building Multiple buildings
Transmission length Short Long
External lines distribution Underground Overhead
Electrical disturbances Low High
Existing lightning rod No Yes
Lightning events Never Already
Equipment sensitivity Low High
Equipment costs Low High
Downtime costs
Low or accep Expensive or
table unacceptable