ND-71548 (E) CHAPTER 2
Page 13
Issue 2
INSTALLATION DESIGN
6.3 Power Distribution Box Requirements
The Power Distribution Box (PDB) should be installed with the following considerations:
1. The AC power source service outlet and the fuse for the junction box should be provided independently of
any equipment other than the switching equipment.
2. A warning notice should be attached to be PDB circuit breaker so that it will not be turned off acciden-
tally.
3. The Power Distribution Box should be installed at a location that is easy to reach.
4. The Power Distribution Box should be installed at a location where the connecting cables extending to the
switching equipment will not be broken accidentally.
5. The PDB cables should be run in such a way that they do not hamper the technician performing the instal-
lation.
6. The Personal Computer (MAT) must have a separate AC service outlet.
6.4 Grounding
System grounding must have a specific ground resistance and AC noise level and is to be connected to a prede-
termined terminal in the PBX.
Standard grounding requirements are shown below.
• Communication grounding: Less than 1 ohm
• Security ground for Module Group: Less than 1 ohm
• Grounding for the line protector of the MDF: Less than 1 ohm
Note: The AC ripple of various types of grounding should be less than 1/2 V-pp.
7. MDF REQUIREMENTS
Either a self-standing or wall-mounted type MDF can be used. The MDF must be equipped with the following
types of terminal blocks.
• Arrester board for C.O. lines and external lines
• Test spring terminals for localization tests
• Local Block terminals
The number of terminals is to be determined according to the circuit configuration of the PBX and the number
of local lines.