Mastech ms5908 User manual

Ω
TEST
mA
VA
ms
Hz%
VA
ms
%
AC
L - N
L - E
N - E
Peak
Z - L
Z - N
Z - E
ASCC
12 A 15 A 20 A HOLD
NEL
V Vd Z RCD GFCI
MS5908
Circuit Analyzer
Operation Manual

01 02
General Instructions
This circuit analyzer is a special test device
designed for AC low-voltage distribution line quick
fault location. With simple operation, accurate
measurement and other features, it can detect
multiple problems on a line, such as causing to
electric shock, electrical fire, abnormal operation
of equipment, etc.
Functions:
• TRMS measuring AC voltage
Artificial load 12A, 15A, 20A measuring line drop
Measuring phase voltage, neutral line (zero line)
voltage to earth, peak voltage, frequency
Measuring phase (live line), neutral line (zero line),
earth line conductor impedance
Identifying 3-wire socket connection mode (zero
for left and live for right, having earth line or not)
Test the reliability of residual current device (RCD)
and response action time
Test the reliability of GFCI action and response
action time
Backlight function and data hold function
•
•
•
•
•
•
•
Warning
Do not use this instrument without reading,
understanding and following the instructions
in this manual. Read and follow them carefully,
as well as all warnings and instructions marked
on the instrument!
To prevent damages to the instrument, it should
not be used for measuring the output of UPS
equipment, nor for measuring adjustable light
and square wave generator!
For measurement accurency during repeated
usage, allow at least 30 seconds between two
consecutive measurements to facilitate
equipment cooling when measuring voltage
drop and cable impedance.
To ensure accurate measurement data, please
check whether there is important load or heavy
load in the line before testing. Turn off the heavy
load, if necessary, then retest.

03 04
1. Input for testing
2. Display
3. Power switch key “ ”
4. Main test item selection key “ ”
5. Data hold key “ ”
6. Backlight function key “ ”
7. Sub test item up selection key “ ”
8. Sub test item down selection key “ ”
9. Test key “ ”
Ω
TEST
mA
VA
ms
Hz%
VA
ms
%
AC
L - N
L - E
N - E
Peak
Z - L
Z - N
Z - E
ASCC
12 A 15 A 20 A HOLD
NEL
V Vd Z RCD GFCI
1
2
3
4
5
6
7
8
9
FRONT PANEL

05 06
L - N N - E Peak
Voltage (V ): eal time display of cable connection
status and display the voltage drop of current load
and measurement results of phase voltage drop
TRMS. This test item includes 3 submenus, namely
load with 12A, 15A and 20A. Press Up “ ”or Down
“ ” selection key on the sub test item to enter the
relevant test item.
One analog load can be added to live line (phase
line) and zero line (neutral line) for the analyser
to measure the voltage drop, and then calculate the
voltage drop of 12A, 15A and 20A load separately.
Under the appropriate test function, press the test
key “ ” to test.
d
Menu Operation
The main test items of the analyser are located on
the bottom of display, including five test items,
namely: voltage (V), voltage drop (Vd),
impedance (Z), RCD and GFCI. Press the main test
item selection key “ ” to select relevant test item.
V Vd Z RCD GFCI
Voltage (V): real time display of TRMS of phase
voltage, wiring status and frequency. This test item
includes 3 submenus, namely phase voltage (L_N)
TRMS, voltage to earth of neutral line (zero line)
(N_E) TRMS, peak voltage (Peak). Press Up “ ”
or Down“ ” selection key on the sub test item to
enter the relevant test item.

07 08
Z - L Z - N Z - E ASCC
RCD: real time display of line connection status,
and display current RCD trigger current and trip
time. The analyser simulates current greater than
30mA between live line and earth line to test the
performance of residual current device. Press the
test key “ ”to test.
GFCI: real time display of line connection status,
and display current GFCI trigger current and trip
time. "GFCI" (Ground Fault Circuit Interrupter) is
a fault leakage protector to earth. The tester
simulates current greater than 5mA between live
line and earth line to test the performance of GFCI.
Press the test key “ ” to test.
12 A 15 A 20 A
Impedance (Z): real time display of line connection
status and frequency, and display of the impedance
test results. This test item includes 4 submenus,
namely phase line (live line), conductor impedance
(Z_L), neutral line (zero line) conductor impedance
(Z_N), erath line conductor impedance (Z_E),
available short-circuit current (ASCC). Press Up
“ ”or Down “ ” selection key on the sub test
item to enter the relevant test item.
The Available Short-Circuit Current (ASCC) feature
can measure the current passing through breaker
when the lines are completely short-circuited.
Under the appropriate test function, press the test
key “ ” to test.

09 10
Other Operations:
Backlight operation: in powered status, press “ ”
key to light up the backlight. If there is no other key
operation for 30 seconds, the backlight will
automatically turn off. You can also turn off the
backlight by pressing the “ ” key.
Auto power off: press the “ ”key to power on the
analyser, the “ ” symbol will show on the display,
which means that the auto power off is enabled.
If the “ ” key is held while pressing “ ” key to
power on the analyser, the “ ” symbol will not
show on the display, which means that the auto
power off is automatically cancelled. When auto
power off function is enabled, if there is no other
key operation for 30 minutes, the analyser will
automatically turn off.
Data hold function: press the “ ” key to enable
data hold function, "HOLD" symbol will show on the
display; when the data hold function is enabled,
press the “ ” key to disable the data hold function.
This function is available only for voltage (V)
measurement item, not available for other
measurement items.
Warning
Testing earth line conductor impedance, RCD
and GFCI will trigger leakage protection device
(RCD or GFCI) over the circuit!
Suggestion: check whether there is important
load over the circuit, then turn off the load,
if necessary, and retest to avoid testing error.

11 12
Wiring test
NEL
The wiring test result will be shown immediately
after the analyzer is plugged to the socket under
test. The analyzer can identify the following wiring
conditions and display the test result on the screen.
Wiring
condition
Normal
No ground
wire is found
The live/zero
line is
connected
inversely.
Other
conditions
Screen display
L E N Caption
Off
On
Flashing
Where any wiring abnormality is found, the
analyzer can only complete partial measurement.
Where there is no earth line, the analyzer can only
measure the phase voltage and voltage drop.
Notes: The analyzer can't detect
1. Circuit voltage, i.e. the voltage between two live
lines;
2. Combined fault;
3. Reverse connection of earth line and neutral line.
Voltage measurement
The normal measured value of phase voltage is
120V±10%, 60Hz. The peak voltage of sine-wave
alternating current is 1.414 times to the effective
value of phase voltage. The voltage to earth of
neutral line shall be less than 2V. In the single-phase
circuit, if the “voltage to earth of zero line” is high,
it indicates that the leakage current in zero line or
earth line is high. In the three-phase circuit with
neutral line, a high “voltage to earth of zero line”
indicates that the three-phase load is imbalanced
or the neutral line is affected by harmonic
interference. Excessive voltage (voltage to earth
of zero line) will result in running deviation or
interruption.
Warning
The maximum measurement voltage shall not
exceed 265V!

13 14
Fault localization and trouble shooting for voltage
problems
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Phase voltage
108-132V
(120V)
198-242V
(220V)
The voltage
is
too high
or
too low.
The circuit is
overloaded.
Redistribute
the circuit load.
High
impedance
points are
found in
switchboard
or circuit.
Locate the
high impedance
and repair
or replace
relevant parts.
The supply
voltage
is
too high
or
too low.
Consult the
power supply
department
Voltage to
earth
of zero line
<2V >2V
Leakage
current
Find the
current source:
Is there any
multipoint
ground?
Does the
equipment
or
device
leak current?
Three-phase
imbalance
Check and
redistribute
the load
>2V<2V
Voltage to
earth
of zero line
Harmonic
interference
Increase neutral
line conductor,
install electrical
filter or use
other methods
to reduce the
harmonic
interference
The supply
voltage
is
too high
or
too low
Consult the
power supply
department
The electron
device in
the circuit
results in the
electric wave
distortion
Revaluate
and
relocate
(if necessary)
the electronic
device
in the circuit
The voltage
is
too high
or
too low.
153-185V
(120V)
280-342V
(220V)
Peak voltage
The supply
frequency
is
too high
or
too low.
Consult
the electricity
department
The frequency
is
too high
or
too low.
60Hz
(50Hz)
Frequency

15 16
Voltage drop (V ) measurement
Dummy load shall be used in the circuit to
measure the load phase voltage and then calculate
the voltage drop. The voltage drop and load phase
voltage will be displayed when the load reaches
12A, 15A and 20A.
In terms of qualified circuit, when measurement
is made in the most remote socket from the
switchboard, the voltage drop shall be less than 5%.
During the measurement of the remaining sockets
of the same area, the farthest socket from the
switchboard shall be measured first and then other
measurements shall be made from the distant to
the near. The reading of the voltage drop shall be
shown on the downward trend.
If the voltage drop exceeds 5% and no obvious
drop of reading is found during the measurement
made near the switchboard, it indicates that the
first connection point goes wrong. In this case,
perform a visual inspection of the wire connection
among the first connection point, equipment and
switchboard and the connection of breaker
(air-break switch). Usually, a high impedance point
generates heat. To locate this problem, infrared
radiation thermometer can be used. In addition, we
can directly measure the voltage on both sides of
the breaker (air-break switch) to locate the point of
failure.
d If the voltage drop exceeds 5%, and during the
measurement made near the switchboard, the
reading drops constantly and no obvious change
is found between the two sockets, it indicates that
the lead wire diameter is too small compared with
the transmission distance, the transmission
distance is too long or the circuit is overloaded.
Under such circumstances, check the cable to see
if the lead wire diameter complies with the required
standard, and measure the lead wire current to see
if it is overloaded.
If the voltage drop exceeds 5% and there is an
obvious change of voltage drop reading between
the two sockets, it indicates that a high impedance
point exists between the two sockets. Usually,
problems are found at the contact, such as poor
connection, loose connector, or socket problem.

17 18
Fault localization and trouble shooting for voltage drop
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Voltage drop
The
voltage drop
is
too high.
Redistribute
the circuit load
The circuit is
overloaded.
Rearrange
the wire in
compliance
with the
relevant
standard.
High
impedance
point exists
between the
circuit and
switchboard.
Repair or
replace the
parts
generating
high
impedance
<5%
Compared
with power
transmission
length,
the wire
is small.
Cable impedance (Z) measurement
If the voltage drop exceeds 5%, analysis on the
impedance of live line and zero line shall be made.
If one datum is obviously larger than the other, it
indicates that the high impedance conductor goes
wrong. Under these circumstances, check all the
conductor connection behind the switchboard. If
impedances are all high, this indicates that the lead
wire diameter is too small for the power transmission
length or the quality of equipment, parts or
connector is poor.
Usually, the earth line impedance is less than 1Ω
to provide a free discharge route for failure current.
According to IEEE, the earth line impedance shall
be less than 0.25Ω to ensure the earthing conductor
to discharge the failure current which threatens all
the equipment. The surge suppression system shall
be grounded reliably to protect the equipment when
this system suffers transient overvoltage.
ASCC is the data calculated based on this formula:
phase voltage/line impedance (Live line + zero line):
ASCC= Phase voltage/
(Live line impedance + Zero line impedance)
Notes:
1. As the test of earth line impedance will trigger
the residual current device due to test principle,
similar device shall be removed from the circuit
before testing.
2. Check the circuit to see if there is heavy load
over the circuit before testing and, if necessary,
turn off the load to avoid wrong test result.
3. Earth connection is required when the cable
impedance is tested in the 2-wire system
(without earth line).

19 20
Fault localization and trouble shooting
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Conductor
impedance
for
live line
and
zero line
The
impedance
is
too high
Redistribute
the
circuit load.
The circuit
is overloaded.
Check the
wire diameter
and
rearrange
the wire
accordingly.
High
impedance
point exists in
the circuit
or
switchboard.
Locate the
high
impedance
and repair
or replace
the parts
The wire
diameter is
too small
for the power
transmission
length.
Check
the wire
diameter and
rearrange
the wire
accordingly.
Locate
the high
impedance
and repair
or replace
the parts
The wire
diameter is
too small
for the power
transmission
length.
High
impedance
point exists
in the circuit
or
switchboard.
The
impedance
is
too high
Conductor
impedance
for
earth line
For
personnel
safety
<1Ω
For
equipment
safety
<0.25Ω
No. 14 line
(2.0mm )
<0.15Ω/m
No. 12 line
(3.3mm )
<0.1Ω/m
No. 10 line
(5.2mm )
<0.03Ω/m
Residual current device (RCD) test
During the RCD test, the analyzer will generate a
low current between live line and earth line by
means of a fixed resistance, which will affect the
current balance between live line and zero line.
According to UL, this current trigger shall be less
than 30mA. The RCD shall response to the current
imbalance by cutting off the power. The analyzer
will display the value of the current triggered (mA)
and response time (ms).
The word “TEST” will be displayed when the button
“ ” is pressed, which means the test is in the
process. RCD shall be triggered within the specified
index to cut off the power of the circuit under test.
If the RCD fails to be triggered, the analyzer will
stop testing automatically after 6.5 seconds.
Analysis on RCD shall be made according to the
test result to see if it goes wrong, is installed
properly or protects the circuit effectively.
Notes:
1. Check the circuit to see if there is heavy load over
the circuit before testing and, if necessary, turn
off the load to avoid wrong test result.
2. Earth connection is required when the RCD is
tested in the 2-wire system (without earth line). .
2
2
2

21 22
Fault localization and trouble shooting
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Check the
circuit and
install
the RCD
according
to the
manufacture
requirement
and
relevant
standard
The RCD
is
installed
improperly
Fail to be
triggered
within
the
specified time
RCD
is triggered
within the
specified
time
RCD test
RCD goes
wrong
Repair or
replace RCD
Fail to
be triggered
(Invalid test)
Triggering time formula specified by UL: T = (20/I)1.43
T: Triggering time (Unit: second)
I: Triggering current (Unit: mA)
GFCI test
During the GFCI test, the analyzer will generate a low
current between live line and earth line by means of a
fixed resistance, which will affect the current balance
between live line and zero line. The GFCI shall response
to the current imbalance by cutting off the power. The
analyzer will display the value of the current triggered
(mA) and response time (ms).
The word “TEST” will be displayed when the “ ” key
is pressed, which means the test is in the process.
GFCI shall be triggered within the specified index to cut
off the power of the circuit under test. If the GFCI fails to
be triggered, the analyzer will stop testing automatically
after 6.5 seconds. Analysis on GFCI shall be made
according to the test result to see if it goes wrong, is
installed properly or protects the circuit effectively.
Notes:
1. Check the circuit to see if there is heavy load
over the circuit before testing, if necessary, turn
off the load to avoid wrong test result.
2. Earth connection is required when the GFCI is
tested in the 2-wire system (without earth line).

23 24
Fault localization and trouble shooting
Measurement
Item
Normal
measurement
result
Fault
measurement
result
Possible
cause
Trouble
shooting
Check the
circuit and
Install the
GFCI
according
to the
manufacture
requirement
and r
elevant
standard
The GFCI
is
installed
improperly
Fail to be
triggered
within
the
specified time
GFCI
is
triggered
within
the
specified
time
GFCI test
GFCI goes
wrong
Repair or
replace GFCI
Fail to
be triggered
(Invalid test)
General technical index
Display: LCD
Overload: “OL” or “>”
Low battery voltage: “ ”
Time for auto power-off: Power off when the keys
aren't pressed for 30 minutes.
Humidity: <80% Relative humidity (0°C~50°C)
Storage temperature: 0°C~50°C <80%
Relative humidity
Physical dimension: 193mm (L)×78mm(W)×38mm(D)
Power source: Six AAA batteries
Weight: 295g (including batteries)
Accuracy index
Accuracy: ±(% reading + words), one-year guarantee.
Reference conditions:
Ambient temperature: 18°C-28°C
Relative humidity: no more than 80%
AC conversion is measured with true RMS
Measurement item Range Resolution Accuracy
Phase voltage 85.0-265.0V Resolution ±(1.0%+ 0.2V)
Peak voltage
Frequency
Voltage drop
Load voltage
Voltage to earth
of zero line
Impedance for
live line, zero line
and earth line
RCD triggering time
RCD
triggering current
GFCI triggering time
GFCI
triggering current
121.0-374.0V
45.0~65.0Hz
0.1%~99.9%
10.0~265.0V
0.0~10.0V
0.00~3.00Ω
1ms~6.500s
30mA~37mA
1ms~6.500s
6mA~9mA
>3.00Ω
0.1V
0.1V
0.1Hz
0.1%
0.1V
0.01Ω
1ms
0.1mA
1ms
0.1mA
±(1.0%+ 0.2V)
±(1.0%+ 0.2Hz)
±(2.5%+ 0.2%)
±(2.5%+ 0.2V)
±(2.5%+ 0.2V)
±(2.5%+ 0.02Ω)
No ensure the accuracy
±(1.0%+ 2ms)
±(1.0%+ 0.2mA)
±(1.0%+ 2ms)
±(1.0%+ 0.2mA)

25 HYS006690
1) The analyzer is powered by six AAA batteries.
2) Cut off the power and pull out the test line.
3) Unscrew the battery compartment and open the cover.
4) Replace the batteries.
5) Ensure the batteries are installed properly
(Do not mismatch polarity)
6) Put back the cover and tighten the screws.
Maintenance
Battery installation and replacement:
Cleaning:
Use soft cloth and neutral cleanser to clean the housing.
Use of abrasive or organic solvent is not allowed.