Atest Gaz Alpa EcoDet XT, User Manual

Page: 17 / 48

www.atestgaz.pl
detectors must be protected against mechanical impacts (e.g. by application of the WM3
mounting bracket, see details in Section 12),
location of detectors must enable scheduled inspection and adjustments of equipment as well as
replacement or disconnection of a detector.
9.2.2 Electric network
Power supplying network for gas detectors must be designed and installed exclusively by persons with
adequate competences or acting in coordination and under supervision of the equipment manufacturer.
The electric power supplying system must be installed in line with the engineering documentation.
The electric network for power supply of detectors must be installed in line with general rules for
design and deployment of I&C 2 systems. Cables and conductors must be secured against damage.
Routing of cables in cable trays is recommended.
All jobs associated with connection of detectors and other components of a gas safety
system must be carried out with power voltage isolated from the control unit. Be aware that
another collaborating system (e.g. a ventilation system controlled by common contact
outputs of relays) can still deliver hazardous voltage, despite the power voltage for the gas
detection system is off.
All interconnections within the system must be made with three-core cables, for instance the
following cable types are recommended: YTKS, OMY and LiYY (for the communication bus).
Detectors Alpa EcoDet XT must be connected by means of a four-core cable. Selection of
appropriate cables is within the responsibility scope of the system designer with consideration of
local conditions at the installation site of the Gas Safety System. Maximum lengths of cable
sections for connections between detectors and a control unit for specific cross-sections of cable
cores are listed in Appendix [4].
For proper selection of cable type take account of voltage drops down interconnecting lines.
Power supply lines for detectors must be designed in such a way that the actual voltage
across the detector terminal must never drop below the minimum permissible level, even
under the most unfavourable power supply conditions with the minimum expected limit of
power supply voltage at the line input (see Section 10).
Springy contacts of terminal blocks are released after depressing the contact button with
a screwdriver.
Detectors can be mounted with the use of mounting holes that are accessible after opening of the
detector enclosure so that the gas inlet faces down. Dimensions of enclosures, spacing of
mounting holes and layout of components inside the detector are shown in Figure 2. D A drilling
template attached to the detector enclosure is recommended for drilling boreholes in walls and
other support structures.
If multi-core strands (commonly referred to as "cables") are used for connection, the ends of these strands
must be secured with terminal ferrules and lugs.
When two or more conductors are to be connected to a single terminal of the device all these conductors
must be clamped beforehand into a common ferrule with a lug (see details in Table 6).
2 Instrumentation and Control
s. 17|25
User Manual: POD-043-ENG R03