10. Live circuit tests
10.1 General
Loop impedance testing requires the operator to test live electrical circuits. Connections should ideally be made when
the circuit dead (isolated). The circuit should then be made live to perform the necessary test, and once the test is
complete the circuit can be isolated again to disconnect or move the test-leads.
WARNING : When you are carrying out live circuit tests, you must observe appropriate precautions for
live working.
WARNING : Live testing should only be performed when no other test options are available.
WARNING : A risk assessment should be conducted to establish if it is safe to perform live testing.
10.2 Warning indication
Tests that use a live circuit or hazardous voltage during the test display a smaller warning triangle during the test.
This is a reminder that hazardous live conditions exist on the circuit under test.
Fig 26: Live test voltage warning – Loop testing and RCD testing examples
10.3 Auto-start (hands-free) option
The MFT-X1 has an auto-start option for Loop impedance and RCD testing. This option is turned off by default but if
you turn it on in SETUP.
When enabled in settings the (hands-free) auto-start function must be primed by pressing a TEST button prior to
connection to the circuit. Once primed the test will start on detection of a compliant live circuit.
The auto-start option is controlled separately for Loop and RCD testing. It is not possible to turn auto-start on for one
type of RCD test and off for others. Auto-start is turned on and off in set up Refer to 15.8.3 AUTO test start on
page 85.
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Live circuit tests
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