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

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
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 [	]	18
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®” Communications		29
	Preparing your MIT430/2 or MIT485/2
	to your PC		29
	Standard download operation		32

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

MIT400/2	www.megger.com	2

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.

MIT400/2	www.megger.com	3

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.

■■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.

■■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.

■■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.

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

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

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

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

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

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

■■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.

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

■■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.

■■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.

■■All covers must be in place whilst conducting tests.

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

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

Safety symbols marked on the instrument

G

F

CATIV 600 V

g

> 600 V

IP54

refer to user instructions

risk of electric shock

600 V ac rms maximum between terminals, and between terminal and earth

Enclosure is dust proof and protected against water splashes

t	Equipment protected throughout
	by Double Insulation.
	Equipment complies with current
	EU directives.
	N13117 Equipment complies with
	current “C tick” requirements.
	Do not dispose of in the normal
	waste stream.

f	Fuse FF 500mA 1000V 30kA

MIT400/2	www.megger.com	4

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

MIT400/2	www.megger.com	5

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.

MIT400/2	www.megger.com	6

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.

MIT400/2	www.megger.com	7

5.Instrument overview

5.1General 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
V	Trms Voltage AC/DC
500 V	Insulation test range –
	Press & hold	button
500 V
L	Insulation test range with gate*–
	Press & hold	L to enable enable range

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

W

Continuity measurement from 0.01W to 999 kW (automatic)

5.1.2 Keypad button functions:

TRMS

Selects AC-Trms or DC mode

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

µF

Capacitance measurement ( automatic)

L	Insulation test lock - Press	and L to

LOCK test ON

Start insulation test Press & HOLD to start

INSULATION test

W

+Nulls test lead resistance to 0.00W when leads short circuit

SET
UP	Enter SETUP configurator (use	and
	L to adjust settings)

SETUP – Select setup function

SETUP – Change function value

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”

W	Insulation testing – Measures REN value
	during insulation test

Capacitance testing – Measures REN value during capacitance test

MIT400/2	www.megger.com	8

5.2 Display contents

Storage and			7	+10	6		5
downloading	21008	0	4100		6100
						+208100.1				Analogue arc and
symbols	9-10							+30	dB
									f4	pointer
	-1510								100.01
	GW				kVs				+35
	MkW								0W
	<![if ! IE]> <![endif]>8				MkWV		kft			Secondary digital
	FG
					Hzkµ A		n	z		display
							µFdB
Warning and	A E B					mV				Main digital
Advisory symbols								Wµ		display
						G mA
	T G R					MkWDW
Symbol	Description			Symbol					Description

GW, MW, kW W, V , mV ,

Units of measurement

Measurement FAIL / PASS

A, mA, Hz, nF, uF

Primary digital readout

A E B

3 Terminal selection status

T G R

Secondary digital readout

REN measurement function enabled

Analogue readout with needle

Transfer data to PC

Buzzer is enabled

Save test measurement to memory

LU

Lock enabled / disabled

Test result recall to screen

F

Hazard voltage warning

Delete test results

G

Warning - Read user manual

Bluetooth® enabled

z

Lead Null is enabled

Battery condition

DW

Difference between two ohms

f

Fuse fail warning

measurements

MIT400/2	www.megger.com	9

5.3 Terminal overview

2 terminal connection	2 terminal connection	3 terminal connection
	+ Guard

MIT400/2	www.megger.com	10

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.

MIT400/2	www.megger.com	11

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:

III 600

g

G

- 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 ).

MIT400/2	www.megger.com	12

2 terminal + Guard connection example:

G

CAT III 600 g

G

- 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:

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

■■Where Live, Neutral and Earth need measuring

■■Comparing continuity of conductors to a ground terminal for difference measurements

■■Testing centre tapped electrical installations.

Telecommunications:

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

MIT400/2	www.megger.com	13