INSULATION TESTING VOLTAGE

► 50 V, 100 V, 250 V, 500 V and 1000 V + PI, DAR

INSULATION TESTING

► Test voltages - 250 V to 1000 V insulation test voltages available
► Test Lock - Locks insulation test on continuously.
► Test voltage display - The actual test voltage is displayed on the smaller digital readout, with the insulation result on the larger digital display.
► Analogue arc - The display also features an analogue arc to replicate the response of a moving coil display. 
► PI and DAR - Polarisation Index (PI) and Dielectric Absorption Ratio (DAR) functions
► 200 GΩ - Insulation testing from 20 GΩ
► Silicone leads - High quality flexible silicone test leads are comfortable to use and prevent measurement errors on higher GΩ ranges.
► Test inhibit - prevents testing if voltages in excess of 50 V are detected when making insulation tests.
► Insulation buzzer - The buzzer can be set to buzz if the insulation resistance is above a preset limit, set via the Setup menu.

CONTINUITY TESTING

► Auto-test - Auto test on circuit contact enables real two handed operation without the need to press the test button.
► 200mA or 20mA - Either 200 mA or 20 mA continuity test currents are available. 20 mA test current will considerably increase battery life.
► Lead null - Lead resistance compensation (NULL) operates up to 9 Ω of resistance.
► Buzzer - ON-OFF selected by simple push button.
► Buzzer limit - Continuity buzzer limit alarm provides adjustment of the maximum resistance the continuity buzzer sounds. This is adjustable from 1 Ω to 20 Ω in 5 steps.

DISPLAY

The display offers a combination of analogue arc and a dual digital readout:

Analogue arc:

► Full display width analogue arc.
► Patented arc display shows essential charge and discharge characteristics not visible on a digital display.
► Single pointer “needle” response is similar to a moving coil meter.
► Logarithmic display for better low insulation value measurements.

Dual digital display:

► Large main digital readout for good visibility of all main measurement results
► Second digital display for additional data such as:
     Insulation test voltage.
     Insulation leakage current.
     Supply frequency (when measuring volts).
     Test mode eg. PI, DAR or TI (Timed mode).

STORAGE & DOWNLOADING RESULTS

►The MIT420 is capable of saving test results for recall to the screen. A simple storage structure allows for a test number and screen results to be recalled individually.

SAFETY

Designed to be exceptionally safe to use, fast detecting circuitry prevents damage to the instruments if accidentally connected to live circuits or across phases. Specifically, all instruments:

► Meet the international requirements of IEC1010-2 and EN61557.
► Live circuit detection inhibits insulation testing on circuits above 50 V.
► Live circuit detection and test inhibit on continuity measurements.
► Default display of live circuit voltage on all ranges.
► Detection and inhibit functions even if the protection fuse has failed.
► Suitable for use on CAT IV applications and supply voltages to 600 V.

Insulation

Nominal test voltages
►MIT420 50 V, 100 V, 250 V, 500 V, 1000 V
Insulation resistance range
►MIT420 200 GΩ
Range Full Scale Accuracy
►1000 volts ±3% ±2 digits ±0.2% per GΩ
►500 volts. ±3% ±2 digits ±0.4% per GΩ
►250 volts. ±3% ±2 digits ±0.8% per GΩ
Analogue range:
►1 GΩ full scale
Short Circuit Current:
►2 mA +0% -50%
Terminal voltage:
►-0% +20% ±1 V
Test Current on load:
►1 mA at min. pass value of insulation specified in BS7671, HD384 and IEC364, 2 mA max.
EN61557 Operating range:
►0,10 MΩ to 1,00 GΩ
Leakage Current:
►10% ±3 digits
Voltage display:
►3% ±3 digits ±0.5% of rated voltage
Polarisation Index (PI):
►10 min / 1minute ratio
Dielectric Absorption Ratio (DAR):
►60 sec / 30 sec ratio

Notes:
(1) All ranges measure from 0,00 MΩ upwards.
(2) Above specifications only apply when high quality silicone leads are being used.

Continuity

Measurement:
►0,01 Ω to 99,9 Ω (0 to 100 Ω on analogue scale)
Accuracy:
►±3% ±2 digits (0 to 100 Ω)
Open circuit voltage:
►5 V ±1 V
Test current:
►200 mA (–0 mA +20 mA) (0.01 Ω to 9.99 Ω)
►20mA (±1 mA ) (10.0 Ω to 99.9 Ω)
Zero offset at probe tips:
►0,10 Ω typical
Lead resistance zeroing:
►Up to 9,00 Ω
Buzzer:
►Variable limit 1 Ω, 2 Ω, 5 Ω, 10 Ω, 20 Ω

Resistance

Measurement:
►0,01 kΩ to 1000 kΩ (0 to 1 MΩ on analogue scale)
Accuracy:
►±3% ±2 digits
Open circuit voltage:
►5 V ±1 V
Short circuit current:
►20 μA ± 5 μA
Voltage range
►0 to 600 V d.c. ±2% ±2 digits
►10 mV to 600 V TRMS sinusoidal (40 to 400 Hz) ±2% ±2 digits
►0 to 1000 V on Analogue scale
►Unspecified input level 0 - 10 mV (40 to 400 Hz)
For non-sinusoidal waveforms additional specification apply:
►±3% ±2 digits 101 mV to 600 V TRMS and ±8% ±2 digits 10 mV to 100 mV TRMS
Default Voltmeter:
►Operates at >25 V a.c. or d.c. on any range except OFF
Frequency:
►40-450 Hz (40 Hz - 99,9 Hz)
►±0.5% ±1 digit (100 Hz to 450 Hz)

Capacitance measurement

►Measurement range: 100 pF to 10 μF
►Accuracy: ± 5.0% ±2 digits Distance by capacitance:

Arithmetic conversion from capacitance measurement on
►Default capacitance measurement: 50nF/m
►Capacitance range: 40 nF/m to 60 nF/m
 

Result storage
►Capacity: >1000 test results
►Download: Bluetooth wireless
►Bluetooth Class: Class II
►Range: up to 10 m
 

Power Supply:

►5 x 1,5 V cells type IEC LR6 (AA, MN1500, HP7, AM3 R6HP) Alkaline NiMH rechargeable cells may be used.
Battery life:
►2200 insulation tests with duty cycle of 5 sec ON /55 sec OFF @ 1000 V into 1 MΩ

Dimensions

Instrument:
►220 x 92 x 50 mm (8.66 in. x 3.63 in. x 1.97 in.)
Instrument + case:
►456 x 178 x 89 mm (18 in. x 7 in. x 3.5 in.)

Weight

Instrument only:
►590 gms, 775 gms with boot (20.73 oz.(27.22 oz.)
Instrument plus case:
►1.75kg (3.86 lb)

Fuse

►Use only a 500 mA (FF) 1000 V 32 x 6 mm ceramic fuse of high breaking capacity HBC 50 kA minimum. Glass fuses MUST NOT be fitted.

Safety Protection

The instruments meet EN 61010-1 (1995) to 600 V phase to earth, Category IV. Refer to safety warnings supplied

E.M.C.

In accordance with IEC 61326 including amendment No.1
Temperature effects
►Temperature coefficient: <0,1% per °C up to 1 GΩ

Environmental

Operating range:
►-10 to +55°C
Operating humidity:
►90% RH at 40°C max.
Storage temperature range:
►-25 to +70°C
Maximum altitude:
►2000 m
Dust and water protection:
►IP54 Protected against dust and splashing water