Earth Measurement In Live Condition (Rearth) - Chauvin Arnoux C.A 6456 Notice De Fonctionnement

4.3

EARTH MEASUREMENT IN LIVE CONDITION (REARTH)

4.3.1 DESCRIPTION OF THE FUNCTION
This measurement is made with a single auxiliary rod (voltage probe) connected to terminal (P),
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yielding a saving of time with respect to a conventional measurement with 2 auxiliary rods.
A specific additional current clamp is necessary to make a selective earth measurement.
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he instrument automatically detects the connection of the voltage and current probes.
When the TEST key is pressed, the instrument:
- checks that the amplitude and frequency of the voltages present are correct,
- checks the resistance of the auxiliary rod,
- interchanges L and N internally if the 2 conductors are reversed in the socket,
- measures the voltage between the TEST key and terminal PE,
If these quantities are correct, the instrument generates, according to the user's selection, a high current
("tripping" mode ) or a low current ("non-tripping" mode
terminals L and PE and measures the voltage drop between terminals P and PE.
If the user selects measurement without tripping (
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measures R (global earth resistance).
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Note : if, during a earth measurement at low current, a earth fault breaker in the circuit still trips, measure the
leakage current with the current probe using the "current measurement" function of the instrument, then
change the measuring current I
TEST
circuit the circuit-breaker concerned and make the next measurement at high current for greater accuracy.
If the user has selected measurement with tripping (or if they have connected the current probe to make
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a selective measurement), the current generated is high (
to prevent the earth fault breaker from tripping (e.g. temporary shunting of the breaker). The instrumen
measures Z (the global earthing impedance), R
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Remarks:
- If the user selects measurement without tripping (
reverts to measurement with tripping and reports the change.
- If the user connects the current probe, it is the current measured by this probe that is used to calculate
R . The lower this current, the more unstable the measurement is likely to be: in this case, smooth the
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measurement using the "SMOOTH" function.
4.3.2 PREPARATION FOR THE MEASUREMENT (CONNECTION)
The instrument must be connected to the network in a live condition and the earth electrode
to be measured must not be disconnected.
=> If necessary, set, in the SET-UP mode :
U (see § 3.2),
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L
the current generated for the measurement at low current :
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www.electronicaembajadores.com
), the current generated is low : the instrument
(see § 4.2.2) with allowance for this leakage current. Otherwise, short-
andt L (the resistive and inductive parts of Z
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) and connects a current probe, the instrument
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on 30mA RCD or more) between
): arrangements may have to be made
).
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