Mitel MIVOICE OFFICE 250, Installation And Administration Manual, Page: 174 / 585

MiVoice Office 250 Installation and Administration Guide
146
Grounding the MiVoice Office 250 HX Controller
With a U.S. system, the MiVoice Office 250 HX Controller must be plugged into a UPS and the UPS
plugged into a properly grounded AC power source. Some effective grounding connections include
the steel frame of the building in which the system is installed, a grounding rod that has been driven
a minimum of 8 ft (2.4 m) into the earth, or a copper— not PVC—cold-water pipe.
With a European system, the equipment chassis must be plugged into a properly grounded AC
power source. The Krone field should also be hard-wired to the building earth.
In addition, all optional IP Single-Line Adapters, trunk gas discharge tubes, and UPS battery
compartments that are used must be properly grounded to the chassis AC outlet. The Mitel DataNet
CommSource division or Mitel Europe sells a surge/spike protector that is equipped with a built-in
ground lug just for this purpose.
The grounding wire should be 10AWG [diameter 6mm] or larger. To provide RFI/EMI protection only,
it should not exceed 25 ft (7.5 m). To provide both RFI/EMI and lightning protection it should not
exceed 10 ft (3 m).
For additional information, refer to the
System Equipment Grounding Guidelines
, part number
835.2845.
To ground the system:
1. Ensure the system AC power source is properly grounded. do not defeat (or leave floating) the
ground wire in the AC power cord.
2. For a U.S. system only, install an AC surge/spike protector with a built-in ground lug and connect
it to:
a. The ground lug (indicated by the symbol ) on each Single-Line Adapter, if used.
b. The ground lug on the back of the chassis, as shown in Figure 14 on
page 144
.
c. Battery compartments, if used.
d. Trunk gas discharge tubes, if used.
3. Continue to “Base Server Modules” on page 1-180 .
If AC power-related problems appear on the system while in operation, one of the following three
methods can be used to test the ground.
• Use a digital multimeter to measure the difference of potential between the equipment cabinet
ground point and the power neutral, and between the cabinet ground point and the third wire
ground. If the voltage measurement exceeds 0.5 V, noise may develop on the system. If this
occurs, call an electrician.
• Use a reliable earth-ground testing device to test the ground point. An earth-ground tester should
be available through the local power company. Look for a reading of 5 ohms or less.
NOTICE
For proper grounding methods, refer to the
System Equipment Grounding Guidelines
, part number
835.2845. See page 133 for additional AC power requirements.