Megger MIT400/2, MIT480/2, MIT430/2, MIT485/2, MIT481/2 User guide

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MIT400/2 Series

Insulation and continuity testers

User guide

User guide contents

1. Introduction 3

2. G Safety Warnings 4

3. Symbols used on the instrument 5

4. General description 6 Unpacking the carton 6 Carton contents (all instruments) 6

5. Preparations for use (all instruments) 7 Batteries 7 Preliminary test lead check

6. General operating intsructions 8 General functions 8 LCD Display 9 Backlight operation 10

7. Test lead connections 11 Standard test leads 11 SP5 Switched probe (not MIT400/2, MIT480/2 and MIT40X) 11

8. AC/DC voltage and frequency measurements 11

17. Battery and fuse replacement 32 Battery condition and replacement 32 Blown fuse indicator 33

18. Preventive maintenance 33

19. Speciﬁcation 34

20. Basic and service errors 36 Basic error 36 Service error: 36

21. Accessories 37

22. Repair and Warranty 39

9. Insulation resistance testing - general 13 Standard insulation resistance testing 13 Insulation resistance testing – timed modes ‘t’, PI and DAR 14

10. MIT40X testing 17

11. Continuity testing [Ω] and buzzer [

12. Resistance measurements (kΩ Range) 19

13. Capacitance measurements 20 Capacitance measurement procedure 20 Distance measurement by capacitance 20

14. Setup options 20

15. Saving, recalling and downloading test results. 23 Saving test results 23 Test results recall 23 PI and DAR recall. 24

16. Deleting test results 26 Procedure for deleting a single test result (refer to Figure 16) 26 Procedure for deleting all test results (refer to Figure 19) 27 Preparing your MIT430/2 or MIT485/2 for “Bluetooth Preparing your MIT430/2 or MIT485/2 to your PC 29 Standard download operation 32

” Communications 29

] 18

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1. Introduction

Thank you for purchasing the Megger insulation test instrument. For your own safety and to get the maximum beneﬁt from your instrument, please ensure that you read and understand the following

safety warnings and instructions before attempting to use the instruments. This user guide describes the operation and functions of the MIT400/2 series of insulation and continuity test instruments. These instruments are designed and manufactured by:

Megger Ltd Archcliffe Road Dover Kent CT17 9EN England

Megger Limited reserves the right to change the speciﬁcation of these instruments at any time without prior notice.

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2. Safety Warnings

2.1 Safety Warnings

Safety warnings and precautions must be read and understood before the instrument is used. They must be observed during use.

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National Health and Safety Legislation requires users of this equipment and their employers, to carry out valid risk assessments of all electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as inadvertent short circuits. Where the assessments show that the risk is signiﬁcant then the use of fused test leads may be appropriate.

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The voltage indicator and automatic discharge features must be regarded as additional safety features and not a substitute for normal safe working practice which MUST be followed.

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The circuit under test must be switched off, de-energized, securely isolated and proved dead before test connections are made when carrying out insulation and continuity tests.

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Test voltages greater than 1000 V dc must not be used on capacitive circuits. Capacitive charges can be lethal.

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Circuit connections and exposed-conductive-parts and other metalwork of an installation or equipment under test must not be touched during testing.

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The Voltmeter function will operate only if the instrument is switched on and working correctly.

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After an insulation test, the instrument must be left connected until the circuit has been discharged to a safe voltage.

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Do not handle test leads above the 1000 V range. (For use in dry conditions only).

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The instrument should not be used if any part of it is damaged.

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All test leads, probes and crocodile clips must be in good order, clean and with no broken or cracked insulation. Verify the integrity of the test leads before making measurements. Only “Megger” approved test leads must be used with this product.

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Ensure that hands remain behind ﬁnger guards of probes/clips.

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National Safety Authorities may recommend the use of fused test leads when measuring voltage on high-energy systems. Fused Leads must be tested independently before use to ensure fuse integrity.

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Replacement fuses must be of the correct type and rating. Failure to ﬁt the correctly rated fuse may result in a safety hazard and may cause damage to the instrument in the event of an overload.

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All covers must be in place whilst conducting tests.

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If this equipment is used in a manner not speciﬁed by the manufacturer, the protection provided by the equipment may be impaired.

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The instrument must be used only by suitably trained and competent persons.

Safety symbols marked on the instrument

G refer to user instructions

F risk of electric shock

CATIV 600 V

terminals, and between terminal and earth

protected against water splashes

> 600 V

600 V ac rms maximum between

IP54 Enclosure is dust proof and

f Fuse FF 500mA 1000V 30kA

t Equipment protected throughout

by Double Insulation.

EU directives.

current “C tick” requirements.

waste stream.

Equipment complies with current

N13117 Equipment complies with

Do not dispose of in the normal

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Installation Category Deﬁnitions:

CAT IV - Measurement category IV: Equipment connected between the origin of the low voltage mains supply and the distribution

panel.

CAT III - Measurement category III: Equipment connected between the distribution panel and the electrical outlets. CAT II - Measurement category II: Equipment connected between the electrical outlets and the user’s equipment.

Measurement equipment may be safely connected to circuits at the marked rating or lower.

2.2 WEEE Directive

The crossed out wheeled bin symbol placed on Megger products is a reminder not to dispose of the product at the end of its life with general waste.

Megger is registered in the UK as a Producer of Electrical and Electronic Equipment. The Registration No is WEE/ HE0146QT.

For further information about disposal of the product consult your local Megger company or distributor or visit your local Megger website.

2.3 Battery disposal

The crossed out wheeled bin symbol placed on the batteries is a reminder not to dispose of them with general waste at the end of their life.

This product contains the following batteries - AA alkaline batteries. They are located under the battery cover at the rear of the instrument. They can be safely removed by following the instructions in the battery replacement section of this guide. Dispose of batteries according to local authority regulations.

Megger is registered in the UK as a producer of batteries. The Registration number is BPRN00142. For Further information see www.megger.com

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3. General Description

3.1 Case contents

There are important documents that you should read and keep for future reference.

3.2 Case contents (all instruments)

1 x MIT400/2 series instrument 1 x Hard carry case 1 x Red/black test lead set with clips 3 x Red/Blue/Black 2.5 kV test lead set (MIT2500 only) 6 x AA (LR6) batteries ﬁtted 1 x Warranty card 1 x Calibration certiﬁcate 1 x Owners CD manual 1 x Quick start guide 1 x SP5 remote switched probe (Not MIT400/2) 1 x Download Manager software CD (MIT430/2 and MIT485/2 only)

IMPORTANT To extend your warranty to 3 years, please register your Instrument at www.megger.com within one month of purchase.

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4. Preparations for use (all instruments)

4.1 Batteries

The Megger MIT400/2 series instruments are supplied with batteries ﬁtted. When batteries become exhausted, refer to section 15 for battery replacement.

Warning: Do not switch the instrument on or connect test leads with the battery cover removed.

4.2 Preliminary test lead check

Functional veriﬁcation

1. Before each use of the instrument visually inspect the test leads, prods and crocodile clips to conﬁrm that their condition is good, with no damaged or broken insulation.

2. Check continuity of the test leads by ﬁrmly shorting the leads together and read the test lead resistance measurement directly from the display, which should be less than 1.0 W.

Note: Supply voltage

This instrument is designed for use on isolated (dead) circuits. Prior to any testing and using an approved method, ensure the circuit to be tested has been fully disconnected and is securely isolated from the supply prior to using the instrument.

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5. Instrument overview

5.1 General functions

5.1.1 Rotary knob position:

Test functions are selected by turning the rotary knob from the OFF position to the desired function. The display will show the initial screen for that function.

Press a black keypad button to change the test mode from the standard measurement, or to select the Backlight and Buzzer ON/OFF.

The rotary knob should always be returned to the OFF position after use. Do not rely on the AUTO OFF function as this unnecessarily wastes battery life.

OFF

Instrument OFF – no live circuit warning

Trms Voltage AC/DC

500 V

Insulation test range –

Press & hold

500 V

Insulation test range with gate*–

Press & hold when selecting test function with rotary knob (* where available)

Continuity measurement from 0.01W to

999 kW (automatic)

button

to enable enable range

5.1.2 Keypad button functions:

TRMS

Selects AC-Trms or DC mode

µF

Capacitance measurement ( automatic)

Insulation test lock - Press and L to

LOCK test ON

Start insulation test Press & HOLD to start

INSULATION test

when leads short circuit

Nulls test lead resistance to 0.00W

SET

Enter SETUP conﬁgurator (use and

SETUP – Select setup function

to adjust settings)

SETUP – Change function value

Insulation testing - Selects DAR, PI, Timed test

(t) or standard measurement (INS)

Insulation testing – Press during test for;

leakage (uA), test voltage (V) or timer (t))

Buzzer ON/OFF – not warning functions

Backlight ON/OFF

SETUP – Change setup value / After test –

SAVE result

A+E+B T+G+R

Swaps measurement connection between

A-B, A-E & B-E (T-R, T-G & R-G)

Continuity testing – Press after “Continuity measurement” to make “difference measurement”

Insulation testing – Measures REN value during insulation test

Capacitance testing – Measures REN value during capacitance test

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5.2 Display contents

Storage and downloading symbols

-1510

-10

2100

+10

Warning and Advisory symbols

Symbol Description Symbol Description

GW, MW, kW W, V , mV , A, mA, Hz, nF, uF

A E B

T G R

Units of measurement Measurement FAIL / PASS

Primary digital readout 3 Terminal selection status

61004100

kVs

A E B

T G R

+20

k V

zkAm

8100.1

G mA

+30

FdB

W WD

100.01

+35

Analogue arc and pointer

Secondary digital display

Main digital display

LU F G z DW

Secondary digital readout REN measurement function enabled

Analogue readout with needle Transfer data to PC

Buzzer is enabled Save test measurement to memory

Lock enabled / disabled Test result recall to screen

Hazard voltage warning Delete test results

Warning - Read user manual Bluetooth® enabled

Lead Null is enabled Battery condition

Difference between two ohms measurements

Fuse fail warning

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5.3 Terminal overview

2 terminal connection 2 terminal connection 3 terminal connection + Guard

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6. General operating instructions

Safety note:

If greater than 25 V appears on the circuit under test the instrument will default to a voltage measurement and display the supply voltage.

On supply voltages over 50 V the instrument will be prevented from performing an insulation test, protecting your instrument from damage.

Note: This limit is increased on MIT481/2 and MIT485/2 to 75 V, but a warning buzzer will indicate voltages above 50 V.

Use extreme care when using or measuring voltages above 30 V, particularly in high energy systems. Fused test leads are available as an optional accessory for local situations where increased protection is required.

Hazardous voltages can exist on the insulation test range all the time the [TEST]

button is locked down.

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7. Input terminals

Test leads connections are as indicated in below, which shows the test lead sockets at the top of the instrument, as well as the switched probe socket and test lead.

7.1 2 terminal test lead connection

Terminal layout - 2 terminal instruments:

- Figure 1

2 terminal connection examples:

CAT III 600 V

- Figure 2

For two terminal instruments (Fig 1), the Red and Black test lead set should be connected to the appropriate sockets on the top of the instrument marked + and –, respectively. (see ﬁgure 1 ).

The RED terminal accepts the standard RED test lead or the Switch Probe lead where supplied.

7.2 2 terminal + GUARD (MIT2500)

The MIT2500 is ﬁtted with a GUARD terminal. The GUARD terminal is used to conduct leakage currents away from the measured circuit to reduce errors.

The GUARD terminal is ONLY used for insulation testing. Refer to Section 9

Terminal layout - 2 Terminal instrument + GUARD:

- Figure 3

For instruments with connection (ﬁgure 3) above, the Red / Black test lead set should be connected to the appropriate sockets on the top of the instrument marked + and –, respectively. (see ﬁgure 3 ).

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2 terminal + Guard connection example:

CAT III 600 V

- Figure 4

The GUARD lead (G) - refer to section 9 Insulation testing. is optional. When used it should be connected to the GUARD conductor, screen, steel wire armoured conductor, or "user added" conductive wire or wrapper, such as foil. This "GUARD" conducts the unwanted surface or "leakage current" away from the measured conductors.

7.3 3 terminal test lead connection

Three terminal connection provides measurement between the 3 pairs of a telecommunication cable (A-B, A-E & B-E) or between single or three phase conductors (L-N, L-E, N-E) and (L1-L2, L1-L3 & L2-L3).

Alternatively, only a single pair can be used (default Red and Black) for conventional 2 wire measurement.

7.3.1 How 3 terminal connection works

The 3 terminal connections allow measurements to be made across any 3 terminals: A-B, A-E or B-E (T-R, T-G, R-G)

This reduces the number of connections necessary to a circuit, especially where live working has been authorised. Once all three leads are connected, measurements between the three terminals can be made.

For example: Electrical testing:

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Where two conductors need to be measured to a screen or shield

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Where Live, Neutral and Earth need measuring

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Comparing continuity of conductors to a ground terminal for difference measurements

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Testing centre tapped electrical installations.

Telecommunications:

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Testing voltage, continuity and Insulation between A, B and E or Tip Ring and Ground, without having to disconnect test leads.

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