The earth connections on each piece of equipment in the system can be used to
connect the shielding of cables.
If a device is placed in a plastic housing, the earth lug of this device also has to be
connected, except for devices that are not provided with an earth lug.
Earthing panels in a single building
In a single building several cabinets or devices are earthed. A licensed contractor
must check the safety earth of this building.
Earthing panels in more than one building
If the wiring extends to separate buildings, use more than one common earth system.
Use the ATS1740 isolator/repeaters to isolate the system databus. This protects the
system against variations in earth potential.
Shielding
The shield of all the shielded cables used in the system should only be connected on
one
side to one common earthing point in a building. If a shielded databus cable is
routed via more than one plastic device, the shield from the incoming and outgoing
cable must be connected.
Figure 3: System shielding example
1.
Mains power with local earth
2.
Mains power connector
3. System
databus
4. Earth
lug
5. Building
1
6.
Building
2
7.
Device in metal housing
8.
Device in plastic housing
9.
ATS control panel
6
ATS125x 4-Door DGP Installation Manual