system] [the grounding grid] shall be measured using the fall-of-potential
method defined in IEEE Std 81. Soil resistivity in the area of the grid
shall be measured concurrently with the grid measurements. Ground
resistance measurements shall be made before the electrical distribution
system is energized and shall be made in normally dry conditions not less
than 48 hours after the last rainfall. Resistance measurements of separate
grounding electrode systems shall be made before the systems are bonded
together below grade. The combined resistance of separate systems may be
used to meet the required resistance, but the specified number of
electrodes must still be provided.
a.
Single rod electrode
- [25 ohms] [_____].
b.
Grid electrode
- [_____] ohms.
3.5.4
Ground-Grid Connection Inspection
All below-grade ground-grid connections will be visually inspected by the
Contracting Officer before backfilling. The Contractor shall notify the
Contracting Officer [_____] hours before the site is ready for inspection.
3.5.5
Liquid-Filled Transformer Tests
The following field tests shall be performed on all liquid-filled
transformers [[_____] kVA and above].
a.
Insulation resistance test phase-to-ground.
b.
Turns ratio test.
c.
Correct phase sequence.
d.
Correct operation of tap changer.
e.
[_____].
3.5.6
Dry-Type Transformer Tests
The following field tests shall be performed on all dry-type transformers
[[_____] kVA and above].
a.
Insulation resistance test phase-to-ground.
b.
Turns ratio test.
c.
[_____].
3.5.7
Circuit Interrupter Switchgear Tests
The following field tests shall be performed on circuit interrupters.
a.
Insulation resistance test phase-to-phase.
b.
Insulation resistance test phase-to-ground.
c.
Closed contact resistance test.
d.
Power factor test.
SECTION 16311A
Page 74
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