|Bond (connect) all existing grounds. There is only one master ground in a building. The ground for your main panel is a good choice.
|All systems capable of being grounded must have the shortest path possible to an earth ground.
|A suitable earth ground is buried 8′ copper rod or a continuous buried copper cold water pipe feed from the water meter.
|All grounds in a building need to be bonded together with #6 or better copper wire. It is preferred to bond all building grounds to a 2/0 bare copper cable ring buried around the perimeter of the building.
|All CO lines need two levels of protection. The carrier provides the first; we provide the second.
|All stations in remote buildings need surge protection on each end of the station tie cable feeding that building.
|Suitable surge protection is defined as that which clamps over voltages to ground as close to the operating voltage of the protected equipment.
|AC power provided to the PBX needs two levels of surge protection. A surge module installed in the AC panel and a surge module installed at each system AC outlet
|Inside building riser cable running vertically between floors must be shielded to reduce the effects of lightning even if no direct strike exists.
|Between buildings either run copper communication cables in aluminum conduit or run copper sheathed direct burial cable.
|Trenches need to be 36″ deep or better with a 6″ sand or crushed rock bottom for drainage.
|The metallic sheath of communications cables entering buildings shall be grounded as close aspracticable to the point of entrance or shall beinterrupted as close to the point of entrance as practicable by an insulating joint or equivalent device.For purposes of this section, the point of entrance shall be considered to be at the point of emergence through an exterior wall, a concrete floor slab, or from a rigid metal conduit or an intermediate metal conduit grounded to an electrode in accordance with Section 800-40(b).
For full Grounding Specs see NEC REFERENCE chapter 8 here