T.I.S. INSTRUMENTS MFT-PRO, Краткое руководство пользователя, Страница: 12 / 24

MFT-PRO
Quick reference guide
EN – 10
4.4. LOOP – MEASURING OVERALL EARTH RESISTANCE (NOTRIP TEST)
CAUTION

The instrument can be used for measurements on installations with overvoltage category CAT III 240V
to earth and CAT III 415V between inputs. Category CAT III is suitable for measurements carried out on
installations inside buildings with low voltage (examples are distribution boards, wirings, switches, fixed
installation sockets, electric motors, industrial equipment).

We recommend holding the alligator clamp respecting the safety area created by the hand protection
(see § 2.4).

Do not measure impedance with rated voltages in the system exceeding a range of 110

240V

10%
(Phase-Neutral, Phase-Earth) and 110

415V

10% (Phase-Phase).
Access the general menu by pressing the HOME key and select function . The instrument
shows the following screen:
4.4.1. Measuring overall earth resistance with no residual current protection tripping
1. Select NoTrip mode by pressing key F1 or touching the relevant icon
2. Select the rated current by pressing key F2 or touching the relevant icon (e.g.:
)
3. Connect the measuring leads as shown in the following figures, which show typical situations: For the
description of other situations, please refer to the user manual.
Measurement of Ra with cable with Shuko-plug Measurement of Ra with measuring leads
Measurement of Ra with remote lead PR400
4. Press
the GO/STOP key on the instrument or the START key on the remote lead PR400. The instrument
starts measuring and provides a result on the display, then gives out a double sound in case the result is
positive.
5. Press the SAVE key or touch the relevant icon to save the result of measurement shown on the
display. Confirm saving by pressing the SAVE key again, or the relevant icon.
For measuring the assumed short-circuit current, checking the coordination of magnetothermal protections,
using the accessory IMP57 and other functions please refer to the user manual.