Frame Ground Connection - Panasonic KX-TAW848 Installation Manual

2.2 Installation of the PBX
2.2.5

Frame Ground Connection

IMPORTANT
Connect the frame of the PBX to earth.
1.
Loosen the screw.
2.
Insert a grounding wire (user-
supplied)*.
3.
Tighten the screw.
4.
Connect the grounding wire to
earth.
* For grounding wire, green-and-yellow insulation is required, and the cross-sectional area of
the conductor must be more than 0.75 mm
• Be sure to comply with applicable local regulations (e.g., law, guidelines).
• Proper grounding (connection to earth) is very important to protect the PBX from the bad
effects of external noise or to reduce the risk to the user of electrocution in the case of
lightning strike.
• The ground wire of the AC cable has an effect against the external noise and lightning
strikes, but it may not be enough to protect the PBX. A permanent connection between
earth and the ground terminal of the PBX must be made.
In most of the continental United States, the ground provided by the "Third wire ground" at the
commercial power outlet will be satisfactory. However, in a small percentage of cases this
ground may be installed incorrectly. Therefore, the following test procedure should be
performed.
Test Procedure
1.
Obtain a suitable voltmeter and set it for a possible reading of up to 250 V AC.
2.
Connect the meter probes between the 2 main AC voltage points on the wall outlet.
The reading obtained should be 108 V AC to 132 V AC.
3.
Move one of the meter probes to the 3rd prong terminal (GND).
Either the same reading or a reading of 0 volt should be obtained.
4.
If a reading of 0 volt at one terminal and a reading of 108 V AC to 132 V AC at the
other terminal is not obtained, the outlet is not properly grounded.
This condition should be corrected by a qualified electrician (per article 250 of the
National Electrical Code).
5.
If a reading of 0 volt at one terminal and a reading of 108 V AC to 132 V AC at the
other terminal is obtained, then set the meter to the "OHMS/RX1" scale, place one
probe at the GND Terminal and the other probe at the terminal which gave a reading
of 0 volt.
A reading of less than 1 ohm should be obtained. If the reading is not obtained, the
outlet is not adequately grounded. See qualified electrician.
34 Installation Manual
Screw
Grounding
wire
To ground
2 or 18 AWG.