General Tools and Instruments CA10 - Manual (Page 9)

MEASURING CONDUCTOR IMPEDANCE
The CA10 can measure and display the impedance of all three circuit
conductors as well as one impedance-related parameter (available short-circuit
current, or ASCC). The three impedance values represent the impedances of the
phase (live) line (Z-L), the neutral line (Z-N), and the earth (ground) line (Z-E).
Available short-circuit current is a measure of the amount of current that would
pass through the circuit’s breaker if all of its conductors were to be short-
circuited. It is calculated as Phase Voltage/(Live line impedance + Neutral line
impedance). Using the terminology of the CA10: ASCC = (L-N)/(Z-L) + (Z-N).
Each of the four impedance parameters is measured and displayed by choosing
it from a submenu made available after the FUNC button has been used to
select Z.
To begin, plug the free end of the test cable into any outlet of the circuit to be
tested. Press the
or button to cycle through the four submenu options
in either direction, as shown in the figure below. The text icon of the parameter
selected for measurement appears at the left of the display. To initiate any test,
press the TEST button.
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