User manual

Wavecom Instruments Portable Appliance Testers Instruction Manual
8
Testing of Electrical Equipment
Many testing personnel have some reservations in testing sensitive, electronic equipment using a 500V DC
insulation test. There is a perceived fear of causing internal damage from over voltage. With the introduction
on the TnT Range of appliance testers, these concerns are alleviated.
The TnT Range of electrical portable appliance testers is safe to test electronic equipment as the tests are
carried from Active-Neutral (shorted by a relay inside the tester) to Earth. No dangerous voltages pass
through in this mode to the internal components of the DUT (Device Under Test). If these tests are done
using an Insulation Tester only and the user tests Active to Neutral, this would be a cause of potential
damage, this is why the TnT product range is far safer to use.
Some changes may be required in certain configurations where fitted surge protection devices (MOV's) in the
DUT may cause a failed test result. Applying 500V in this these situations can cause the surge protection
devices to trip, therefore conducting the applied voltage to earth, thus showing a failure of insulation. In these
instances the test voltage should be changed to 250V then retest. If DUT still fails, check with the DUT
Operators Manual or an electrician. [for details see - ‘Double Insulation Test’ 250/500VDC to change test
voltage].
Under these circumstances, it would be difficult for any damage to occur to either the surge protection device
or the DUT, as there is insufficient current generated by the TnT-el appliance tester.
Leakage Test:
If there are any doubts with insulation testing of the equipment, the standard
(AS/NZ3760 since 2001) allows for an alternative test method. A Leakage Test can be performed instead.
(The TnT – Series are designed to perform these tests).
NOTE: 10Amps MAXIMUM Resistive Load only (Standard TNT - Series units).
A Leakage Test applies power to the Device Under Test (DUT) and measures the imbalance of leakage
current from the DUT between the active and neutral conductors. The leakage is tested to the limits specified
in the standard and a Pass/Fail result as well as a digital reading is provided to ensure that the user gains as
much information as necessary.
Earth Continuity Test:
The TnT-el conducts earth continuity tests at Approx. 200mA. Continuity tests at higher currents are not
required and are not recommended on certain equipment as this can cause severe damage or premature
failure to the DUT under test (as per AS/NZ3760).
3 Phase Testing: *Optional
3 Phase appliances can be tested by the TnT series appliance testers. This test is carried out by using the
adaptor connection socket. As the insulation tests are from Phase to Earth, only a 500V insulation test is
required. These adaptors can be made by your electrician or purchased as an accessory. [See ‘Optional
Accessories’ for details - when ordering please state plug configuration of 3 phase plug.]
Please note: (The TnT cannot perform 3 Phase Leakage test. Contact Wavecom Instruments Pty Ltd
for the appropriate tester).
To Change Test Voltage
To change the test voltages select the "change ins" from the options menu. Please refer to the special
functions section of this manual.
Please Note: The TnT - Series will automatically default to 500VDC when restarted.