Installing the Stratum 3 Clock
Task List: Install the Stratum 3 clock
694
SI Installation and Upgrades
June 2004
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Connect AC Power to Stratum 3 Clock Cabinet
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The clock cabinet requires a 120 VAC, 15 amp receptacle. The green wire ground provided by the
receptacle is sufficient. The clock cabinet does not require a ground connection back to the single-point
ground.
Check and Connect Commercial AC Power
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1
Before powering up the system, check the AC power using a KS-20599 digital voltmeter (DVM)
(or equivalent).
2
Set the DVM to the 250 volt range.
3
Carefully measure the voltage between the hot and neutral side of the receptacle. The neutral wire
is white, the hot wire is black.
4
Verify the meter reads 106 to 128 VAC. If not, have a qualified electrician correct the problem.
5
Measure the voltage between the neutral and ground side of the receptacle. The ground wire is
green.
6
Verify the meter reads 0 VAC. If not, have a qualified electrician correct the problem.
7
Set all cabinet power modules OFF. Plug the AC power cable into the receptacle.
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Connect DC Power and Ground to Stratum 3
Clock Cabinet
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Provide power for the clock cabinet from the same DC power plant as the DEFINITY ECS.
Ground the clock cabinet to the DC power plant.
Connect Clock Cabinet Grounding
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1
Measure and cut a 6 AWG (#40) (16 mm
2
) wire long enough to reach from the clock cabinet to
the ground discharge bar in the DC power plant.
2
Insert 1 end of the wire into the ground lug on the clock cabinet and tighten the screw.
