7. Continuity testing and resistance measurement
Fig 11: Continuity
7.1 General information
7.1.1 Basic functions
Instruments in the MFT-X1 range can check continuity and measure resistance from 0.01 Ω up to 999 kΩ, which
means that you no longer need to use a separate meter to make resistance measurements.
A buzzer function is also provided which can speed up routine testing but, when this function is used, resistance
measurements are limited to a maximum of 2.00 kΩ (or 1 kΩ on the analogue arc).
Analogue arc
The display also has an analogue arc, which is useful when you are investigating poor or intermittent connections.
The analogue arc is a logarithmic scale, so it gives good resolution for low values of resistance but displays values up
to 999 kΩ without the need to change scale (limited to 1 kΩ in buzzer mode).
Measurement test current and voltage
When checking the continuity of a conductor, circuit or connection, the instrument uses a default test current of
200 mA or greater, and a voltage of between 4 V to 5 V. This complies with the requirements of IEC 61557 part 4.
For circuits with higher resistance than this, the test current is reduced automatically. In all cases, the actual test
current is shown at the bottom left of the main display area as highlighted below:
Fig 12: Continuity test current
Alternatively, you can use a test current of 10 mA for continuity checking. Although this does not comply with
general electrical compliance testing, it is satisfactory for routine testing, and it extends the life of the instrument’s
batteries. The 10 mA option is also useful when testing Neutral to Earth. This can be done on a live installation as
long as suitable precautions are taken for working on live circuits, if the Neutral to Earth voltage is < 1.0 V.
The 10 mA will not generally trip 30 mA RCDs.
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MFT-X1
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Continuity testing and resistance measurement
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