2-5-11 Flashcards
Any high voltage testing of cable has the possibility of causing __?__.
insulation failure
OSHA 1910.269(o) does not include testing of control circuits because such circuits are tested at ultra-low voltages.
false
The maintenance VLF test voltage is normally __?__ of the acceptance level test voltage.
80%
The three most common methods of testing cable insulation are using a megohmmeter, doing a VLF Test or a(n) __?__Test
hi potential
Before doing a High-Potential test on a cable, a __?__ test should be first performed to pre-qualify the insulation.
polarization index
Of all the methods used to insulate cable, polybutene-impregnated paper is the best because it has infinite resistance.
false
Tracks that form in insulation and will eventually lead to a faulted cable are called __?__.
water trees
A Hi-Pot test normally applies __?__ to the cable under test.
over voltage
When testing a single primary cable, the guard circuit of a megohmmeter is used to prevent __?__ from affecting the insulation resistance reading.
surface current leakage
A polarization index test is performed to __?__ the insulation on a cable.
pre-qualify
When using a megohmmeter to test a single cable, the __?__ is connected to the conductor.
line terminal
A megohmmeter measures the resistance of a cable by performing a calculation using __?__.
ohm’s law
If a cable test as good, it means the cable never has to be tested again.
false
The suggested testing time for a very low frequency test is __?__.
30 min
High Potential tests are conducted at two or more times the rated cable voltage.
true
A __?__ test performed with VLF equipment is considered a non-destructive test.
diagnostic
A High-Potential test can be performed with AC or DC voltage.
true
The most common frequency used in a VLF test is __?_
0.1 Hz
If a primary cable has a defect, the VLF test will force the insulation defect to penetrate the insulation.
true
A megohmmeter test is used to pinpoint insulation faults on primary cable so that repairs can be made.
false
The intent of a voltage maintenance test performed on primary cable is to __?__ of the cable and check its serviceability.
detect the deterioration
Three reasons a water tree may become an electrical tree are lightning impulse, excessive test voltage levels, and __?__.
switching surges
There are no formal studies or recognized organizations that approve of VLF testing.
false
