Megger MFL205 User manual

MFL205
Fuse Finder
INSTRUCTION MANUAL

This document is copyright of:
Megger Limited, Archcliffe Road, Dover, Kent CT17 9EN. ENGLAND
T [phone] F [phone] www.megger.com
Megger Ltd reserves the right to alter the specification of its products from time to time without notice. Although
every effort is made to ensure the accuracy of the information contained within this document, it is not warranted or
represented by Megger Ltd to be a complete and up to date description.
This manual supersedes all previous issues of the manual. Please ensure that you are using the most recent issue of this
document. Destroy any copies that are of an older issue
Safety Information
Understand and follow the operating instructions carefully
WARNING
Identify hazardous conditions and actions that could cause BODILY HARM or DEATH
When using test leads or probes, keep your fingers behind the finger guards
Personal protective equipment should be used if there are ACCESSIBLE HAZARDOUS LIVE PARTS in the installation
where measurement is to be carried out
Use the meter only as specified in this manual otherwise, the protection provided by the meter may be impaired
Verify the instruments correct operation before each use
Do not apply more than the rated voltage, as marked on the meter, between the terminals or between any terminal
and earth
Use caution with voltages above 30 V AC rms, 42 V AC peak, or 60 V DC. These voltages pose a shock hazard
Do not use the meter around explosive gas or vapor
To reduce the risk of fire or electric shock do not expose this product to rain or moisture
Lead, probe and clip assemblies to be used for MAINS measurements shall be RATED as appropriate for MEASUREMENT
CATEGORY III or IV, according to EN 61010- 03, 1 and shall have a voltage RATING of at least the voltage of the circuit
to be measured
DO NOT USE if the internal white insulation layer of the test leads is exposed
DO NOT USE the test leads, probes or clips above the maximum ratings of CAT Environment or voltage that are
indicated each component
Do not apply or remove the test leads on or around uninsulated hazardous live conductors, where a potential to cause
electric shock, electrical burns or arc flash exists
CAUTION
1. The Megger MFL205 is designed to be used by suitably qualified or competent people who are familiar with the
electrical installation they are connecting to
2. All safety warnings within this manual must be read and understood before use of the MFL205. Failure to comply
may lead to serious injury or damage to the installation or meter
3. If possible, the system should be powered down when connections are made or removed
4. Always connect the black (negative) test lead before the red (live) test lead. The red lead should always be removed
before the black lead
5. The transmitter and receiver are designed for indoor use only and should not be used outside or in damp or wet
environments
6. Before use, always prove the meter is functioning correctly, as described in this manual
7. Do not expose the meter to extremes of temperature or high humidity
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MFL205 Fuse Finder

Symbols as marked on the Meter and Instruction manual
FRisk of electric shock
tEquipment protected by double or reinforced insulation
cConforms to EU directives
Conforms to UKCA directives
Do not discard this product or throw away
CATIII
Measurement category III: Equipment connected between the consumer unit and the electrical outlets.
CATII
Measurement category II: Equipment connected between the electrical outlets and the user’s equipment.
Unpacking and Inspection
Megger MFL205 Transmitter
Megger MFL205 Receiver
Crocodile Clips (one black, one red)
User Manual
Carry case
Battery
Optional Accessories
Megger MSA1363 – UK BS1363 Socket Adapter
Megger MTF230 – Type F (Schuko) Socket Adapter
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MFL205 Fuse Finder

Meter Description
Transmitter
There is no power switch on the transmitter. Injection of the test signal will automatically start upon connection to the
mains supply (110/230 V 50/60 Hz)
Receiver
The button on the receiver has 3 functions: ON/OFF/RESET
To turn on, press and release the ON/OFF/RESET button. LED indicator (2) will light and glow red and the receiver will
start beeping
To reset, with the receiver switched on, push and immediately release the ON/OFF/RESET button. This will reset the
scanning function memories to zero and should be carried out with the receiver held away from the distribution board/
cables being scanned
To power down, press and hold down the ON/OFF/RESET button for longer than 1 second
NOTE: To conserve battery, the receiver will automatically power down after 3 minutes of inactivity. To resume
scanning, press the ON/OFF/RESET button as detailed above
Function Check
Before using the MFL205, the following function check should be performed. First, turn on the receiver and check that
the LED is red and a steady beeping tone is emitted. If either of these functions are not operating, replace the battery
and re-check
A low battery indication is given if the LED is green and the beeps emitted are longer in duration. This indicates >20%
battery life remains and the battery should be replaced as soon as possible
Connect the transmitter and turn on the supply. Move the scanning probe of the receiver over the housing of the
transmitter
The beeping from the receiver should become very rapid, or change to a continuous tone, and the LED should turn
green.
Performing the “Function Check”
RECEIVER TRANSMITTER
Receiver
1. Scanning Probe
2. LED Indicator
3. Signal LED Indicator
4. Buzzer
5. ON/OFF/RESET Button
6. Battery Cover
Transmitter
1. Power Indicator light
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MFL205 Fuse Finder

Operating Instructions
1. Perform the function check, as described above
2. At the distribution board or consumer unit, place the scanning probe in contact with the face of the circuit breaker
or fuse carrier at a right angle to the direction of the breaker/carrier body. Run the scanning probe steadily along
the row of breakers/fuses. The frequency of the beeping will increase and become very rapid or continuous and the
LED will turn from red to green when it encounters a stronger signal
3. Continue to scan across the rest of the breakers/fuses
4. If the receiver led starts to flash red, remove the scanning probe, press the reset button and start the process again
Scanning the breakers of fuses
NOTE: The first strong signal you encounter may not be the strongest signal there is. Do not stop scanning as the
technology used is comparative and it is essential that all breakers and fuses are scanned to ensure the strongest signal
is indicated
5. Repeat the process. With each scan, the receiver automatically adjusts the sensitivity to disregard any weaker
signals.
6. Continue scanning until only one breaker causes the rapid/continuous beeping and the LED turns green. This is the
breaker protecting the circuit the transmitter is connected to
7. Isolate this circuit and the receiver will revert to a red LED and steady beep
8. Confirm the correct breaker/Fuse has been isolated by checking the power light on the transmitter is extinguished
9. Prior to undertaking any work, a safe isolation test should then be performed on the circuit using a suitable 2-pole
tester and proving unit
Alternative scanning options
Due to the different designs of circuit breakers it may be unclear using the above method which of two breakers is
emitting the stronger signal, particularly if it appears to be from an area between two adjacent breakers. In the event of
this happening, using one of the two methods below should aid pinpoint identification of the correct breaker
1. Reset the receiver and scan the breakers on the opposite side of the switch
Scanning opposite side of the breaker or fuses
2. Reset the receiver and rotate it through 90° and scan one side of the breaker
3. If the signal is still not clear, reset again and scan the opposite side of the breaker with the receiver still held at 90°
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MFL205 Fuse Finder