Measurements; Measurement Of Interference Voltages Dc + Ac - Sonel MRU-11 User Manual

Earth resistance measurements significantly different from other measurements performed to
assess the protection against electric shock. They require a thorough knowledge of the structure of
the earthing system, the phenomena occurring during the measurements and the skills of coping with
adverse outdoor conditions. Earthing system tests/measurements require adequate knowledge and
measuring equipment, which will be able to maximally facilitate these examinations.

4.1 Measurement of interference voltages DC + AC

Additional information displayed by the meter
U >100V!, >100V
N
and a continuous beep ,
NOISE! and
U xxV!, >40V and a continuous
N
beep , NOISE! and
U xxV!, >24V, NOISE! and
N
NOISE!
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Measurements

Voltage at test terminals is higher than 100 V, the meas-
urement is blocked.
Where xx is the value of interference voltage. Voltage at
test terminals is higher than 40 V but lower than 100 V, the
measurement is blocked.
Where xx is the value of interference voltage. Voltage at
test terminals is higher than 24 V but lower than 40 V, the
measurement is blocked.
The interference voltage is lower than 24 V, but with a high
value - the measurement result may be affected by addi-
tional uncertainty.
MRU-11 – USER MANUAL
In measuring functions,
before START button is
pressed, the meter moni-
tors the measuring volt-
age at the terminals (be-
tween E socket and S / H
sockets) and the interfer-
ence voltage value is
displayed on the screen.
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