Function Description; Continuity Measurements "•))) - Metrix MX 435D Notice De Fonctionnement

Chapter II
3.

FUNCTION DESCRIPTION

• The maximum voltage assigned to terminals is 480 Vrms.
• • • • For all functions, "I" is displayed when ranges are exceeded.
• • • • The simultaneous flashing of the 5 RCD range lights shows the user that
the device will turn off in one minute (except if the Test button is activated
again).
3.1. Continuity measurements "•)
A source generates a current of 200 mA through the resistance being measured. Its value
can be deduced from the voltage drop at its terminals.
Measurements must not be performed on live installations or instruments.
Method:
• Turn the selector switch to • • • • )
• Connect the 2 test leads to the COM and Ω terminals.
On an installation, the COM terminal will be connected, for example, to the building's
earth connection and the Ω terminal will be used to check that the different points on
the ground circuit (radiator blocks, lights, piping ...) are correctly linked to this earth
connection.
• Continuity is measured automatically, without having to press the "TEST" button.
• The resistance is displayed in Ω on the LCD screen and a beep is emitted if R < 2 Ω.
If an "I" is displayed the resistance value is > 20 Ω.
• With a mains voltage of 50/60 Hz, for example, the beep is modulated. You must
stop measuring immediately and eliminate the voltage present.
The instrument is protected, non-fused, up to 480 Vrms. The instrument returns to
normal working conditions after a maximum period of 30 seconds.
Switching the measurement leads between COM and Ω inverts the power flow and makes it
possible to obtain:
R1 +
R2
R avg = , R1 and R2 being measured with opposing flow directions.
2
Norm NFC 15-100 recommends that the continuity test be carried out using a voltage
source of from 4 V to 24 V, using direct or alternating current of at least 200 mA.
The test is satisfactory if the measured resistance is less than 2 Ω, this guarantees that all
the metal parts are correctly earthed.
Digital Earth Tester
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