AT&T 518-600-016 manual System Grounding Requirements

over ac circuit wire. When crossing station wire over ac circuits is unavoidable, try to maintain a 3-foot clearance.

●Use conduit for wiring runs whenever possible. Be sure that the conduit is grounded. If the conduit is not grounded, run a No. 12 wire from the conduit and terminate it on the ac earth ground, or bond it to the earth ground.

●Run station wire on the baseboard or as close to the floor as possible.

●Run shielded wire for the stations that are having interference problems. Ground the shield of the wire and bond it to the ac ground.

●Visually verify that the ac power line is grounded and that it is bonded to the protector ground. Use an Ideal circuit tester (or equivalent) or a VOM to verify that the ac outlet is grounded. (See “AC Outlet Tests” on page 2-7.) If the outlet is not grounded, run a No. 12 wire from either the grounding terminal or the center screw of the ac outlet to the location where the ac power line is earth grounded, and terminate it.

Install Built-in speakerphone stations (BIS-10, INS-22, BIS-34).

●Install a Z200A filter at the MERLIN II system station. If interference is still present, install another Z200A filter at the control unit.

●If there is radio interference on the CO lines, use a ZIOOA filter.

●Change the ac outlet to a different branch circuit.

●Move the control unit to a different location.

System Grounding Requirements 2-11