Seaward PAC 1500Xi - Manual (Page 5)

Type B tests This is a form of Earth Continuity test utilising test currents of 100mA
at an open circuit voltage of 500mV RMS. The low current prevents
damage to the appliance under test, the low voltage will assist the
detection of loose connections and is less likely to break down
surface corrosion films at defective connections. For this reason when
conducting such a test it is vital to ensure that good connection is
made between the test leads and the device under test.
It is advisable to consult the manufacturer to obtain the appropriate test current and test
point(s) on the accessible conductive parts for each type of equipment.
Connections
The appliance should be connected as per figure 1 ensuring that all connections are
firmly made and that the Earth Bond Test Leads are correctly inserted according to the
colour coded plugs and sockets.
The PAC1500Xi should be set to EARTH TEST selecting the appropriate test current
for the appliance.
Procedure
The test should be initiated by depressing the TEST push-button. This button must
remain pressed throughout the duration of the test. If for any reason the test button is
released the test will be aborted.
At the start of the test the READY indicator will extinguish and the TIMEOUT indicator
will light showing test signals are being applied to the appliance. The LCD display will
show the Earth Bond resistance throughout the test.
At the end of the 6 second test the TIMEOUT indicator will extinguish and the LCD dis-
play will continue to hold the last test reading. Test signals are no longer applied to the
appliance. The TEST button can be released.
After a further period of 6 seconds the LCD display will switch off and the READY indi-
cator will illuminate showing that the PAC1500Xi is ready to commence a further test.
Until the READY indicator lights further depressions of the TEST button will not initiate
tests. The TEST button must be released and depressed to initiate a test. Continual
depression of the switch will not result in a continuous sequence of tests.
The test should be repeated for each area of exposed metalwork.
Notes on Results
It may be noted that the earth bond resistance of the appliance may change during the
test. Before rejecting the appliance care should be taken to ensure that the following
mechanisms are not causing the variance;
1) Bad connection of the test leads, this is particularly critical at low test currents.
Ensure that the connections are firmly made onto clean surfaces.
2) Thermal effects. Wire increases in resistance with an increase in temperature. At
high current levels the PAC1500Xi is capable of generating sufficient heat within con-
nection leads which will be detected by the high resolution of the display. Care should
be taken to ensure that repeated tests do not damage the appliance.
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