Installation
2-7
2.2.5
Frame Ground Connection
IMPORTANT!!!
Connect the frame of the main unit to ground.
1. Loosen the screw.
2. Insert the grounding wire.
3. Tighten the screw.
4. Connect the grounding wire to ground.
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 VAC.
2. Connect the meter probes between the two main AC voltage points on the wall outlet. The
reading obtained should be 108-132 VAC.
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 108-132 VAC 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 108-132 VAC 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 a qualified electrician.
DIGITAL SUPER HYBRID SYSTEM
To ground
screw