2.2 Installation of the Hybrid IP-PBX
2.2.5
Frame Ground Connection
IMPORTANT
Connect the frame of the Hybrid IP-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 Hybrid IP-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 Hybrid IP-PBX. A permanent connection
between earth and the ground terminal of the Hybrid IP-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.
40
Installation Manual
Screw
Grounding
wire
To ground
2
or 18 AWG.