B&K Precision 308A - Manual - Manual (Page 9)

Caution: Never turn the function dial whilst the
button is depressed. This may damage
the instrument. Never touch the circuit
under test during insulation testing.
When testing is complete ensure that the test
buttonis released before the test leads are
disconnected .
This is because the system may be charged up
and it must be allowed to discharge through the
tester's Internal discharge resistor .
— Continuity testing (Resistance tests) :
Warning: Ensure circuit are not live before
commencing testing .
Select the 20 range by rotating the range
selector and connect the test leads to the
instrument .
Short the tips of the leads . Press and hold
down the test button by twisting it a quarter
turn clockwise .
The display will show the resistance of the test
leads . Adjust the
ZERO control to set the
reading of zero .
Connect the test leads to the circuit under test .
Ensure the circuit is not live by checking that
the live circuit indicator does not lit .
Read the value of resistance from the LCD .
— AC voltage test :
Set FUNCTION switch to ACV . Connect test
leads to circuit being measured , Press TEST
button and read the value of voltage form the LCD.
— Always check the following before testing :
The "Battery Low" indicator is not showing.
There is no visual damage to the instrument or
test leads.
— Test Lead Continuity:
Select the CONTINUITY function and 20W range.
Short the test leads together.
An over-range ( "1" ) indication will mean that the
leads are faulty or instrument fuse is blown. (See
"Fuse Replacement" section)
— Insulation Resistance Testing:
Warning: Insulation tests should be conducted on
circuits that are de-energised . Ensure
circuits are not live before commencing
testing.
Select the required test voltage (250V , 500V
or 1000V) by rotating the function switch .
Attach the test leads to the instrument and to
the circuit to be tested (see connect diagram) .
If the "LIVE CIRCUIT" is lit , do not press the
test button and disconnect the instrument from
the circuit . The circuit is live and should be de
-energised before further testing .
Press the test button .
The value of insulation
resistance in megohms
will be displayed .
Connect Diagram
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