Megger MFM 10-M User manual

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MFM 10-M
Sheath Fault Location System
USER GUIDE
Issue: B (12/2022) - EN
Article number: 128313372

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Consultation with Megger
3
Consultation with Megger
The present system manual has been designed as an operating guide and for reference.
It is meant to answer your questions and solve your problems in as fast and easy a way
as possible. Please start with referring to this manual should any trouble occur.
In doing so, make use of the table of contents and read the relevant paragraph with great
attention. Furthermore, check all terminals and connections of the instruments involved.
Should any question remain unanswered or should you need the help of an authorized
service station, please contact:
Megger Limited Megger Germany GmbH (Baunach)
Archcliffe Road
Kent CT17 9EN
T: [phone]
F: [phone]
E: [e-mail]
Dr.-Herbert-Iann-Str. 6
D - 96148 Baunach
T: [phone] – 0
F: [phone]
E: [e-mail]
Megger Germany GmbH (Radeburg) Megger USA
Röderaue 41
D - 01471 Radeburg / Dresden
T: [phone] – 0
F: [phone]
E: [e-mail]
Valley Forge Corporate Centre
2621 Van Buren Avenue
Norristown, PA 19403 USA
T: [phone]
F: [phone]
Megger
All rights reserved. No part of this handbook may be copied by photographic or other means unless Megger
have before-hand declared their consent in writing. The information in this document is subject to change without
notice and should not be construed as a commitment by Megger. Megger cannot be made liable for technical or
printing errors or shortcomings of this handbook. Megger also disclaims all responsibility for damage resulting
directly or indirectly from the delivery, supply, or use of this matter.

Terms of Warranty
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Terms of Warranty
Megger accept responsibility for a claim under warranty brought forward by a customer
for a product sold by Megger under the terms stated below.
Megger warrant that at the time of delivery Megger products are free from manufacturing
or material defects which might considerably reduce their value or usability. This warranty
does not apply to faults in the software supplied. During the period of warranty, Megger
agree to repair faulty parts or replace them with new parts or parts as new (with the same
usability and life as new parts) according to their choice.
This warranty does not cover wear parts, lamps, fuses, batteries and accumulators.
Megger reject all further claims under warranty, in particular those from consequential
damage. Each component and product replaced in accordance with this warranty
becomes the property of Megger.
All warranty claims versus Megger are hereby limited to a period of 12 months from the
date of delivery. Each component supplied by Megger within the context of warranty will
also be covered by this warranty for the remaining period of time but for 90 days at least.
Each measure to remedy a claim under warranty shall exclusively be carried out by
Megger or an authorized service station.
This warranty does not apply to any fault or damage caused by exposing a product to
conditions not in accordance with this specification, by storing, transporting, or using it
improperly, or having it serviced or installed by a workshop not authorized by Megger. All
responsibility is disclaimed for damage due to wear, will of God, or connection to foreign
components.
For damage resulting from a violation of their duty to repair or re-supply items, Megger
can be made liable only in case of severe negligence or intention. Any liability for slight
negligence is disclaimed.
Since some states do not allow the exclusion or limitation of an implied warranty or of
consequential damage, the limitations of liability described above perhaps may not apply
to you.

Contents
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Contents
Consultation with Megger.......................................................................................... 3
Terms of Warranty...................................................................................................... 4
Contents ..................................................................................................................... 5
1Safety Instructions ...................................................................................... 7
1.1 Basic Notes ................................................................................................... 7
1.2 General Safety Instructions and Warnings ..................................................... 8
2Technical Description.................................................................................10
2.1 System Description.......................................................................................10
2.2 Technical Data .............................................................................................12
2.3 Connections, Controls and Display ...............................................................13
3Commissioning...........................................................................................14
3.1 Electrical Connection: Typical Procedure ......................................................15
3.2 Electrical Connection: Special Applications ...................................................17
4Operation ....................................................................................................21
4.1 Switching On the System..............................................................................21
4.2 General Operation ........................................................................................21
4.3 Security Mechanisms....................................................................................23
4.4 System Settings............................................................................................24
4.5 Operating Modes ..........................................................................................25
4.5.1 Testing the Insulation - ..........................................................................25
4.5.2 Prelocating a Fault - ...............................................................................27
4.5.3 Pinpointing a Sheath Fault - ....................................................................29
4.5.4 Burning - .................................................................................................31
4.6 Concluding the Test......................................................................................33
5Processing Log Data ..................................................................................34
6Updating the Firmware ...............................................................................35
7Maintenance and Care................................................................................36

Safety Instructions
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1Safety Instructions
1.1 Basic Notes
This handbook contains basic instructions for the commissioning and operation of the
MFM 10-M. For this reason, it is important to ensure that the manual is always available
to authorised and trained personnel. Operating personnel should read the manual
thoroughly. The manufacturer will not be held liable for any injury or damage to personnel
or property through failure to observe the safety precautions contained in this handbook.
The specific standards and regulations in each country must also be observed.
Important instructions concerning personnel, operational and technical safety are marked
in the text as follows:
Symbol Description
WARNING
Indicates a potential danger of an electric shock that may result in fatal or
serious injury.
CAUTION
Indicates a potential danger that may lead to slight or moderate injury.
The notes contain important information and useful tips for using the
system. Failure to observe them can render the measurement results
useless.
It is important to observe the generally applicable electrical regulations of the country in
which the device will be installed and operated, as well as the current national accident
prevention regulations and internal company directives (work, operating and safety
regulations).
After working on the system, it must be voltage-free and secured against reconnection as
well as having been discharged, earthed and short-circuited.
Use genuine accessories to ensure system safety and reliable operation. The use of other
parts is not permitted and invalidates the warranty.
This system and its peripheral equipment may only be operated by trained or instructed
personnel. Anyone else must be kept away.
The system may only be installed by an authorised electrician. DIN VDE 0104 (EN 50191),
DIN VDE 0105 (EN 50110) and the German accident prevention regulations (UVV) define
an electrician as someone whose knowledge, experience and familiarity with the
applicable regulations enables him to recognise potential hazards.
Repair and maintenance work may only be performed by Megger or authorised service
partners. Megger recommends having the system tested and maintained at a Megger
service centre once a year.
Megger also offers its customers on-site service. Please contact your service centre as
needed.
Safety precautions
Labelling of safety
instructions
Working with products
from Megger
Operating staff
Repair and
maintenance

Safety Instructions
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This device is designed for industrial use according to EN 55011. When used at home it
could cause interference to other equipment, such as the radio or television.
The interference level from the line complies with the limit curve B (living area), the
radiation level complies with the limit curve A (industrial area). Once the living area is
sufficiently far away from the planned area of operation (industrial area), equipment there
will not be impaired.
1.2 General Safety Instructions and Warnings
The operating safety is only guaranteed if the delivered system is used as intended.
Incorrect use may result in danger to the operator, to the system and the connected
equipment.
The MFM 10-M must only be operated while being properly installed in the test van.
The thresholds listed in the technical data may not be exceeded under any circumstances.
Condensation during the operation of Megger products may result in danger to persons
and devices through voltage arc-over. Prevent condensation before and during the
measuring mode by cooling the measuring systems sufficiently. The operation of Megger
products in direct contact with water, aggressive substances and inflammatory gases and
vapours is prohibited.
The MFM 10-M is built to be robust and can withstand the stresses it can expect to be
subjected to in demanding everyday use. Nevertheless, it is a precision measuring device
which needs to be treated with the appropriate care. This applies in particular to the
connection cable and the clamps, which play an important role in ensuring the device
remains safe while the results of measurements remain precise.
The system may only be operated whilst it is in perfect working condition. In the event of
damage, irregularities or malfunctions that cannot be resolved with the assistance of the
operating instructions, the system must be shut down immediately and labeled
accordingly. In such an event, the relevant management must be informed. Please
contact Megger Service immediately, to eliminate the malfunction. The system may only
be started up again once the malfunction has been eliminated.
Five safety rules
The five safety rules must always be followed when working with HV (High Voltage):
1. De-energise
2. Protect against re-energising
3. Confirm absence of voltage
4. Earth and short-circuit
5. Cover up or bar-off neighbouring energised parts
Using cardiac pacemaker / defibrillator
Physical processes during operation of high voltage may endanger
persons wearing a cardiac pacemaker or defibrillator
when near these high
voltage facilities.
Electromagnetic
radiation
Use only as intended
Procedure in the event
that the device
malfunctions

Safety Instructions
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Fire fighting in electrical installations
•According to regulations, carbon dioxide (CO2) is required to
be used as extinguishing agent for fighting fire in electrical
installations.
•
Carbon dioxide is electrically non conductive and does not leave
residues. It is safe to be used in energized facilities as long as
the minimum distances are maintained. A CO2fire extinguisher
must be always available within electrical installations.
•If, contrary to the regulations, any other extinguishing agent is
used for fire fighting, this may lead to damage at the electrical
installation. Megger disclaims any liability for consequential
damage. Furthermore, when using a powder extinguisher near
high-voltage installations, there is a danger that the operator of
the fire extinguisher will get an electrical shock from a voltage
arc-over (due to the powder dust created).
•It is essential to observe the safety instruction on the
extinguishing agent.
•Applicable is DIN VDE 0132.
WARNING
Be careful when working with high voltage
Working on high voltage systems and equipment – especially in non-
stationary operation – requires particular care and safety-
conscious
action on the part of test personnel. VDE regulations 0104 on setting up
and operating electrical test systems, as well as EN 50191 and national
standards and regulations must be strictly adhered to.
•The System generates a dangerous voltage of up to 10. This is
supplied via a HV connection cable to the test object.
•The test system may not be operated without supervision.
•Never fail to use safety equipment or put it out of operation.
•To prevent dangerous charge accumulation, earth all metal parts in
the vicinity of the high voltage equipment.
•When high voltage is shut off, the cable under test is discharged by
an internal discharge device. This discharge device is designed for a
maximum test object capacity in compliance with the technical data.
This value must not be exceeded. The discharge device may
otherwise become damaged and charge may remain in the test
object. The cable must therefore always be discharged in
accordance with the applicable safety regulations, e.g. discharged
using a discharge rod and then be shorted before the danger zone is
accessed.

Technical Description
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2Technical Description
2.1 System Description
For power cables and particularly for cables in the field of telecommunication, an
undamaged cable sheath is an exceptionally important prerequisite to avoid serious cable
faults which would influence the quality of supply. The conservation of the value of a cable
is also determined by the attention paid to the condition of the sheath. Irrespective of the
tests and diagnoses of the core insulation, the early recognition and elimination of sheath
faults has a stabilising effect on the operational quality of a cable system.
The sheath fault location system MFM 10-M was developed for this purpose. This device
is used for the general measurement of insulating cable sheaths and, due its numerous
applications, is regarded as the universal device for these measuring requirements.
Accordingly, the MFM 10-M permits in the easiest way the testing of cable sheaths and
prelocation and pinpointing of cable sheath faults.
To detect sheath faults, the MFM 10-M works in test mode with a voltage of up to 10 kV
(negative polarity), which also permits cables with a thicker outer sheath to be tested.
The prelocation of a detected fault takes place using the voltage drop method, in which
the current, voltage and resistance before and after the fault location are determined and
considered in relation to the cable length. The necessary measuring and calculation steps
take place automatically and, after a few seconds, the distance to the fault is displayed.
Due to the bipolar measurement, falsifying thermoelectric and galvanic influences can be
detected and mathematically eliminated.
The available current of up to 750 mA also enables the “burning” of difficult sheath faults,
if necessary.
For sheath fault pinpointing, the device provides several possibilities. One of these is a
pulsed DC output voltage, which is used in combination with an earth fault locator as the
ESG to locate the sheath fault by the step voltage method. A second method is to pinpoint
the fault with a so-called A-Frame while the MFM 10-M transmits a low frequency (3 or
4.8 Hz) signal.
Intended use
Function