used in live-maintenance by the barehand method shall be electrically evaluated by
means of dc high potential tests.
B3.2.1. Electrical Test Electrodes. Generally insulated aerial devices are delivered
or retrofitted with test electrodes permanently installed on the inside and outside
surfaces of the insulating portion of the upper boom for the purpose of monitoring
dialectic leakage current as required by paragraph 3.3.5 of ANSI A92.2. Prior to
conducting the following tests, it will be necessary to ascertain that all hydraulic and
pneumatic lines and leveling mechanisms, which bridge the insulating portion of the
boom, are still connected to the test electrodes.
B3.2.2. High-Voltage DC. A dc test set with a capability of 400-kV and 2.5-
milliamperes is recommended for testing FRP booms certified by the manufacturer
for use on line to line rms voltages up to 345-kV. However; a dc test set of 100-kV
and 5-milliamperes may be used if both dry and wet tests as discussed later are
B3.2.3. Boom Orientation. Raise the lower boom so as to clear the nesting cradle by
at least 2 feet (0.6 meters) for each kV of test voltage. Bring the upper boom to a
horizontal position and hold for 15 minutes to allow any contaminants to settle
horizontally in the hydraulic tubing before testing. Prior to and during electrical
testing the truck chassis the truck chassis must be grounded. Refer to Paragraph
4.2.3. The case of the test set must also be connected to the chassis ground.
B3.2.4. Dry Test Procedure. Test the major upper boom insulation system which
includes the FRP boom, hydraulic lines, and leveling mechanism. The high voltage
terminal of the test set is connected to the upper (platform end) test electrodes. The
lower test electrode is connected to the chassis ground or to the test set ground.
Raise the voltage smoothly to the appropriate test level shown in Table B2 and hold
for three minutes. Read and record the dielectric leakage current. Some of the
incipient breakdowns that can be detected with this test include deterioration of the
insulation resulting from ionization along the surface or internal voids, moisture,
absorption, and structural aging. Any significant change in dielectric current values
from previous test values warrants an investigation into the cause. If the dielectric
current exceeds 0.5 microampere per kV of applied test voltage, the boom should be
cleaned, rewaxed and retested.
B3.2.5. Wet Test Procedure. Any new insulated boom as delivered has a waxed or
silicone surface to repel water. This surface must be carefully maintained and
replaced as necessary. A dry boom with a chalky or nonwater repelling surface may
pass the dry dielectric test and still be a virtual short circuit on a moist morning or
after a brief shower. Therefore, a wet test is recommended for all test voltage, and is
required if the test set is limited to 100-kV rating. To conduct the
B-4 (FIST 3 - 29 5/90)