Step 4: Ground The System - Toshiba Strara CTX Series Installation And Maintenance Manual

Strata CTX670 Installation

Step 4: Ground the System

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 3-11, for grounding points "A" and "B"). An insulated conductor must connect the frame
ground terminal on the Base Cabinet to a cold water pipe or the building ground (point "B").
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
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 CTX670 system consists of more than one cabinet, you must install the bonding connection
plates that come attached to each expansion cabinet. Refer to
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
WARNING! 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.
3-18
Figure 3-11, the grounding path between point "A" and the single point
Figure 3-10.
Figure 3-9. Connect the mother board
Figure 3-11.
Strata CTX I&M September 2002