Earth The System - Toshiba strata CT Installation & Maintenance Manual

Step 3: Earth the System
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WARNING!
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Strata CT I&M Manual October 2000
The system requires a solid earth ground for proper operation and safety. The AC power
cord(s) already contains a conductor for the "third wire ground" provided by the commercial
power outlet (see Figure
must connect the frame ground terminal on the Base Cabinet to the Main Building Earth
Point (MBEP).
Before connecting the system to the AC power source, measure the impedance of the building
ground reference. If the ground path connected to the system has an impedance of 1 ohm or
more, a better ground must be installed. In
"A" and the single point ground "B" must be less than 0.25 ohms.
The "third wire ground" coming from the primary AC power outlet must be dedicated and
must be routed through the same conduit as the phase conductors serving the system. The
conductor connected to the frame ground (FG screw) on the system power supply must be
insulated and comply with the general rules for grounding contained in ie Regs, 16th Edition,
but must not depend on the cord and plug of the system.
If the Strata CT system consists of more than one cabinet, you must install the bonding
connection plates that come attached to each expansion cabinet. Refer to
the mother board ground wires and the intercabinet ground wires per
Wrap the cable mesh shield (part No. B50MT) around the 25-pair communication cables that
carry stations over tip and ring, per
Failure to provide a proper ground may be a safety hazard to service
personnel or lead to confusing trouble symptoms. In extreme cases,
system failure may result because the system is not properly protected
from lighting or power transients.
2-10, for grounding points "A" and "B"). An insulated conductor
Figure
Figure 2-9.
Strata CT Installation
2-10, the the grounding path between point
Figure
Figure
2-8. Connect
2-10.
2-17