Megger MFT1720 User Manual

M
MFT1700/1800 Series
Multifunction Tester
Quick Start Guide
GSAFETY WARNINGS
n Safety warnings and precautions must be read and understood before
the instrument is used. They must be observed during use.
n The circuit under test must be switched off, de-energised and isolated
before test connections are made when carrying out insulation and
continuity tests.
n Continuity of protective conductors and earthed equipotential bonding
of new or modified installations must be verified before carrying out an
earth fault loop impedance test, RCD or earth testing
n Do not touch circuit connections and exposed metalwork of an
installation or equipment under test. Under fault conditions the system
earth could become hazardous live.
n Do not touch the earth stakes, test leads and their terminations
(including connections to the earthing system under test) if an
installation earth fault can arise unless adequate precautions are taken.
n The ‘live circuit warning’ and ‘Automatic discharge’ functions are
additional safety features and should not be regarded as a substitute
for normal safe working practices.
n Do not move the rotary switch positions while a test is in progress.
n Do not operate the instrument or connect it to any external system
if it shows any visible signs of damage or if it has been stored for
prolonged periods in unfavourable conditions.
n Do not operate the instrument or connect it to any external system
if the battery compartment or casing is open or any parts of the case
(including keypad, selector switch, display window, etc.) are missing.
n Always disconnect the instrument from all systems while batteries are
being changed or the fuse replaced
n Do not replace the rechargeable cells in the MFT1730 and 1835 with
non-rechargeable “dry” cells and attempt to charge the cells. This can
cause explosion or fire.
n Do not operate the charging equipment supplied with the MFT1730 or
MFT1835 in damp or wet environments or outside. All test leads must
be removed from the instrument while charging.
n After insulation tests, capacitive circuits must be allowed to discharge
before disconnecting test leads. Locking the Insulation test ON should
only be used where there is no risk of a circuit holding a charge.
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Megger MFT1720 Specifications

General

Type	Multifunction Tester
Insulation Resistance Test Voltage	250 V, 500 V, 1000 V
Continuity Test Current	200 mA
Earth Resistance Test	Yes
RCD Test	Yes
IP Rating	IP54
Operating Temperature	-10 °C to +55 °C
Storage Temperature	-25 °C to +70 °C
Battery Type	Rechargeable Li-ion
Insulation Resistance Range	0.01 MΩ - 1000 MΩ
PSC/PFC Range	0 - 20 kA
RCD Test Currents	10 mA, 30 mA, 100 mA, 300 mA
Frequency Range	45 to 65 Hz
RCD Trip Time Range	0 - 2000 ms
Display	Backlit LCD

Summary

Safety Warnings

Live Earth Safety Precautions

Instrument Overview and Display

Instrument Overview

Provides a visual guide to the instrument's controls and indicators.

Display Layout

Explains the different elements shown on the instrument's display screen.

Measurement Functions

Terminal Panel

Details the physical connections and ports on the instrument's terminal panel.

Voltage, Frequency, and Phase Rotation

Explains how to measure voltage, frequency, and determine phase rotation.

Continuity Measurement

Describes the process for measuring resistance and continuity of conductors.

Insulation and RCD Testing

Insulation Measurement

Details the procedure for performing insulation resistance tests.

RCD Trip Time Measurement

Explains how to measure the trip times of Residual Current Devices (RCDs).

RCD Ramp Testing

RCD Ramp Testing

Describes how to measure trip current of RCDs using a ramp test.

Loop Impedance Testing

Circuit Loop Impedance

Explains how to measure circuit loop impedance for fault loop path analysis.

R1+R2 Loop Impedance

Details the process for measuring R1+R2 impedance for protective conductor resistance.