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This test can also be used to verify a dedicated circuit. A measurement
greater than 0.1 volts indicates that the receptacle under test is
not on a dedicated circuit. If the LED display is flashing, the unit
is unable to detect a ground. In the absence of a ground, the
ground-to-neutral voltage can not be misused. A reading of high
on the LED display indicates that the ground-to-neutral voltage is
greater than 2 volts.
Estimated Load Measurement
The estimated load test is indicated on the LED display by "5=". A current
draw confirms that the receptacle under test is not on a dedicated circuit.
This is a peak reading, which will be reset by pressing the display advance
button, and cycling through the menu until the LED display shows "5="
again.
This is the final measurement in the programming menu. Pressing and
holding the display advance button will move back to line voltage, the first
test in the menu.
Ground Impedance Measurement
WARNING
An indication of "No Ground" on the wiring indicators indicates a
safety hazard is present. Do not perform the ground impedance test-
ing under these conditions.
The ground impedance measurement is a separate measurement and is out-
side the programming menu. To measure ground impedance, the SureTest
must be removed and re-inserted into the receptacle while pressing the dis-
play advance button.
The St-1D checks ground impedance by pulsing 15 amperes from hot-to-
ground to ensure that the resistance is less than 1 Ohm. This test can not
be performed on a GFCI receptacle. The pulse will trip the GFCI.
1. Remove the ST-1D from the receptacle
2. Re-insert the St-1D into the receptacle while pressing the center button
3. The LED display will show "L-G" to indicate the ground impedance test
4. The LED display will show "6=" to indicate that the measurement is being
taken.
5. Ground impedance is measured and displayed
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The ground impedance of an equipment chassis can be checked with #61-
175 ground continuity adapter.
1. Attach the #61-175 ground adapter to the ST-1D
2. Clip the alligator lead from the adapter to the equipment chassis
3. Insert the St-1D into the receptacle while pressing the center button The
LED display will show "L-G" to indicate the ground impedance test
4. The LED display will show "6=" to indicate that the measurement is being
taken.
5. Ground impedance is measured and displayed
G.F.C.I. Testing
The ST-1D applies 6mA to ground through a fixed resistor to trip the GFCI.
A functional GFCI will disconnect the power. The reset may be at the outlet
or at the panel.
WARNING
When testing 3-wire outlets, do not proceed with the GFCI test if the
Wiring Indicator lights indicate a "No Ground" condition exists.
Repair the ground circuit first.
1. Operate the test button on the GFCI installed in the circuit. The GFCI
should trip. If it does not, replace the GFCI. If it does trip, reset the
GFCI.
2. Insert the ST-1D into the receptacle.
3. Press the GFCI test button on the ST-1D for 6 seconds.
4. The actual current being applied to ground will be displayed.
5. (6mA is the nominal current sent through the fixed resistor. The actual
current will vary depending on the line voltage per UL1436.)
6. The tester will apply the current and count up to 6.5 seconds.
• If the GFCI is functioning properly, the circuit will disconnect, and the
LEDs on the ST-1D will go out. When the circuit is reset, and power
is returned, the LED display will show the actual time to trip.
• If the GFCI fails to trip, the LED display will show ìbAdî, which indi-
cates that the GFCI may be installed incorrectly, or the GFCI may be
defective.
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