3.20.1
Distribution Conductors, 600-Volt Class
Conductors shall be tested to verify that no short circuits or accidental
grounds exist using an instrument which applies a voltage of approximately
500 volts to provide a direct reading in resistance.
3.20.2
Counterpoise System Test and Inspection
Continuity of counterpoise system shall be inspected at accessible
locations. Continuity of counterpoise system to the vault grounding system
in manhole closest to the vault shall be tested.
3.20.3
Progress Testing for Series Helipad Lighting Circuits
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NOTE: Progress testing should be specified when
replacing or modifying existing series airfield,
heliport, or helipad lighting circuits since
interruption time is usually critical; however,
progress testing on completely new series helipad
lighting circuits is not normally necessary.
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A megger test shall be conducted on each section of circuit or progressive
combinations of sections as they are installed. Each section or
progressive combination of sections shall be checked with a megohmmeter
providing a voltage of approximately 1000 volts to provide a direct reading
in resistance, and document results. Faults indicated by these tests shall
be eliminated before proceeding with the circuit installation.
3.20.4
Electrical Acceptance Tests
Acceptance tests for series and multiple helipad lighting circuits shall be
performed only on complete lighting circuits. Each series and multiple
lighting circuit shall be tested for high voltage insulation resistance.
3.20.4.1
Low Voltage Continuity Tests
Each series circuit shall be tested for electrical continuity. Faults
indicated by this test shall be located and eliminated before proceeding
with the high voltage insulation resistance test.
3.20.4.2
High-Voltage Insulation Resistance Tests
Each series lighting circuit shall be tested for high-voltage insulation
resistance by measuring the insulation leakage current using a suitable
high-voltage test instrument with a steady, filtered direct current output
voltage and limited current. High-voltage tester shall include an accurate
voltmeter and microammeter for reading voltage applied to the circuit and
resultant insulation leakage current. Voltages shall not exceed test
values specified below.
a.
Test Procedure: Both leads shall be disconnected from regulator
output terminals and support so that air gaps of several inches
exist between bare conductors and ground. Cable sheaths shall be
clean and dry for a distance of 300 mm one foot from ends of
cables and exposed insulation at ends of cables. Ends of both
conductors of the circuit shall be connected together and to
high-voltage terminals of test equipment, and test voltage applied
SECTION 16525A
Page 35
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