Earthing Principles And Requirements; Earthing And Power Supply - ABB FOX615 Installation & User Manual

P R E P A R I N G F O R I N S T A L L A T I O N
2.3

Earthing principles and requirements

2.3.1

Earthing and power supply

20
Please note:
The installation of stacked subracks in standard ETSI racks requires other
arrangements, since there is normally no room for the evacuation of the
heated air at the rear of the racks.
Please note:
If the equipment is stacked, a heat deflection shield R7AI is installed on top
of each FAMO1 or FAMO1-F to evacuate the heat generated in the subrack.
Depending on the rack, the top equipment does not require deflection.
Please note:
A heat deflection shield R7AI installed below the subrack might help to
remove the hot air produced below.
Considering the above it is possible to create the layout for the FOX equip-
ment and heat deflection devices in the rack.
The FOX615 is a telecommunication equipment compliant to protection
class 1.
The FOX615 is designed for earthing and power supply principles according
to ETSI EN 300 253 V2.1.1, Figure 2: "Example of a CBN (Common Bonding
Network)/MESH-Bonding Network configuration with common DC return
conductor connected to the CBN at multiple points".
For details of the Common Bonding Network principles, refer to ETSI EN 300
253 V2.1.1.
In the FOX subrack the 0-volt potential of the (external) power supply is
directly connected to the mechanical construction of the subrack and the
(internal) electronic ground GND which is fed via the backplane to the units.
The negative power supply voltage U
subrack. The filtered voltage (U
for local conversion.
The subrack requires reliable earthing / bonding to the CBN. The subrack
mounting flanges are conductive and provide a conductive contact to the
rack if the rails of the rack also provide a conductive surface. If the rack does
not provide a conductive surface or is not connected to the CBN, one of the
four screws used for the fixing of the subrack to the rack can be used as ter-
minal for the subrack earthing via an earthing cable.
(-48/-60 V ) is first filtered in the
T DC
) is then fed via the backplane to the units
TF
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FOX615 Installation