SEFRAM MW3366 User manual

USER MANUAL
MW3366
600A
TRMS AC+DC
CLAMP METER

1
1) SAFETY
This manual contains information and warnings that must be followed for operating the
meter safely and maintaining the meter in a safe operating condition. If the meter is
used in a manner not specified by the manufacturer, the protection provided by the
meter may be impaired.
Observe proper safety precautions when working with voltages above 30 Vrms, 42.4
Vpeak or 60 VDC. These voltage levels pose a potential shock hazard to the user. Do
not expose this product to rain or moisture. The meter is intended only for indoor use.
Keep your hands/fingers behind the hand/finger barriers (of the meter and the test
probe assembly, where applicable) that indicate the limits of safe access of the hand-
held parts during measurements. Inspect lead wires, connectors, and probes for
damaged insulation or exposed metal periodically. If any defects are found, replace
them immediately. Only use the test probe assembly provided with the meter or a UL
Listed test probe assembly to the same meter ratings or better.
Optional offer premium test probe assembly using silicone lead wire insulation, at
agent’s discretion, is equipped with white inner insulation layers as wear indicators.
Replace them immediately if any of the white layers has become visible.
Disconnect the test leads from the test points before changing functions.
The meter meets IEC/EN/BSEN/CSA_C22.2_No./UL standards of 61010-1 Ed. 3.1 and
61010-2-032 Ed. 4.0 to Measurement Categories CAT III 600V and CAT IV 300V AC &
DC
The accompanied test probe assembly meets IEC/EN/BSEN/CSA_C22.2_No./UL
standards of 61010-031 Ed. 2.0 to the same meter ratings or better. The 61010-031
requires exposed conductive test probe tips to be ≤ 4mm for CAT III & CAT IV ratings.
Refer to the category markings on your probe assemblies as well as on the add-on
accessories (like detachable Caps or Alligator Clips), if any, for applicable rating
changes.

2
INTERNATIONAL SYMBOLS
Marking of Electrical and Electronic Equipment (EEE). Do not dispose of this
product as unsorted municipal waste. Contact a qualified recycler.
Refer to the explanation in this Manual.
Possibility of electric shock
Earth (Ground)
Meter protected throughout by Double Insulation or Reinforced insulation
Fuse
Direct Current (DC)
Alternating Current (AC)
3 Three-phase Alternating Current
Application around and removal from hazardous live conductors is permitted
Brief Information about Measurement Categories
Measurement Category IV is applicable to test and measuring circuits connected at
the source of the building’s low-voltage MAINS installation. Examples are
measurements on devices installed before the main fuse or circuit breaker in the
building installation.
Measurement Category III is applicable to test and measuring circuits connected to
the distribution part of the building’s low-voltage MAINS installation. Examples are
measurements on distribution boards (including secondary meters), circuit-breakers,
wiring, including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed
installation, and equipment for industrial use and some other equipment such as
stationary motors with permanent connection to the fixed installation.
Measurement Category II is applicable to test and measuring circuits connected
directly to utilization points (socket outlets and similar points) of the low-voltage MAINS
installation. Examples are measurements on MAINS CIRCUITS of household
appliances, portable tools and similar equipment.
2) EUROPEAN DIRECTIVES AND UK STATUTORY REQUIREMENTS
The instruments conform to EUROPEAN (CE) Low-Voltage Directive 2014/35/EU,
Electromagnetic Compatibility Directive 2014/30/EU, and RoHS 2 Directive 2011/65/EU
plus amendment Directive (EU) 2015/863. The instruments also conform to the UK
(UKCA) Electrical Equipment (Safety) Regulations 2016, Electromagnetic Compatibility
Regulations 2016, and The Restriction of the Use of Certain Hazardous Substances in
Electrical and Electronic Equipment Regulations 2012.

3
3) PRODUCT DESCRIPTION
1) Antenna area for Non-Contact
EF-Detection
2) Jaw center indicator (with DCA
polarity), at where best current
accuracy is specified
3) Rotary Selector to turn the
power ON/OFF and Select a
function
4) 3-5/6 digits 6000 counts
numeric LCD display
5) Input Jack for all functions
EXCEPT non-invasive DCA,
DC+ACA, or ACA current
functions
6) Common (Ground reference)
Input Jack for all functions
EXCEPT non-invasive DCA,
DC+ACA, or ACA current
functions
7) Push-buttons for special
functions & features.
8) Jaw trigger for opening the
clamp jaw
9) Hand/Finger Barrier to indicate
the limits of safe access of the
meter
10) Clamp Jaw for DC or AC
current magnetic field pick up
11) Additional center indicator for
AmpTipTM Low-current function,
at where best AmpTipTM current accuracy is specified

4
4) OPERATION
WARNING: Before and after hazardous voltage measurements, test the voltage
function on a known source such as line voltage to determine proper meter functioning.
ACV, DCV, DC+ACV, & Line-level Hz functions
Inputs are made through the test lead terminals COM/+. Defaults at ACV* Function.
Press SELECT button momentarily to select DCV, DC+ACV or Line-level Hz function
in sequence.
Note:
*ACV (and hence AC+DCV & Line-level Hz) function is equipped with digital low-pass
filter, and is capable of dealing with VFD (Variable Frequency Drives) signals. It also
improves ACV reading stability in noisy electrical environments.

5
Electric Field EF-Detection
The meter displays “EF” when it is ready. Signal strength is indicated as a series of
bar-graph segments on the display together with variable beep tones.
●Non-Contact EF-Detection: An antenna is located along the top-right end of the
stationary clamp jaw, which detects electric field surrounds energized conductors. It is
ideal for tracing live wiring connections, locating wiring breakage and to distinguish
between live or earth connections.
●Probe-Contact EF-Detection: For more precise indication of live wires, such as
distinguishing between Live and Ground connections, use one single probe to test via
terminal COM for direct contact EF-Detection with best sensitivity.

6
NOTES for Non-Invasive (Clamp-on) Current Measurements:
NOTE
(Application and Removal of the Clamp-on Jaws) For non-invasive current
measurements, press the jaw trigger and clamp the jaws around conductor(s) of only
one single pole of a circuit for load current measurement. Make sure the jaws are
completely closed, or else it will introduce measurement errors. Enclosing conductor(s)
of more than one pole of a circuit may result in differential current (like identifying
leakage current) measurement. Align the conductor(s) to the Jaws center indicators
(Regular or AmpTip™ indicators where applicable) as much as possible to get the best
measuring accuracy. For removal, press the jaw trigger and remove the jaws from the
conductor(s).
Adjacent current-carrying devices such as transformers, motors and conductor wires
may affect measurement accuracy. Keep the jaws away from them as much as
possible to minimize influence.
NOTE
Do not use the meter to measure currents above the rated frequency (400Hz).
Circulating currents may cause the magnetic circuits of the Jaws reach a hazardous
temperature.

7
Non-Invasive AmpTipTM Low-Current Functions:
ACA, DCA, DC+ACA & Hz
Input is made via the clamp jaws with best accuracy specified near the jaw tip area for
small conductors low-current measurements. Defaults at ACA function. Press SELECT
button momentarily to select the subject functions in sequence.
Non-Invasive Regular Current Functions:
ACA, DCA, DC+ACA, & Hz
Input is made via the clamp jaws with best accuracy specified at the jaw center for
regular current measurements. Press SELECT button momentarily to select the subject
functions in sequence.

8
 Resistance, Continuity, & Diode functions
Inputs are made through the test lead terminals COM/+. Defaults at  Resistance.
Press SELECT button momentarily to select the subject functions in sequence.

9
NOTE
When using Diode test function, normal forward voltage drop (forward biased) for a
good silicon diode is between 0.400V to 0.900V. A reading higher than that indicates a
leaky diode (defective). A zero reading indicates a shorted diode (defective). An OL
indicates an open diode (defective). Reverse the test leads connections (reverse
biased) across the diode. The digital display shows OL if the diode is good. Any other
readings indicate the diode is resistive or shorted (defective).
NOTE
Using Resistance, Continuity or Diode function in a live circuit will produce false results
and may damage the meter. In many cases, the suspected component(s) must be
disconnected from the circuit to obtain an accurate measurement reading.
Capacitance functions
Inputs are made through the test lead terminals COM/+.
NOTE
1. Using Capacitance function in a live circuit will produce false results and may
damage the meter. In many cases the suspected component(s) must be disconnected
from the circuit to obtain an accurate measurement reading.

10
2. When using Capacitance function, discharge capacitor(s) before making any
measurements. Large value capacitors should be discharged through an appropriate
resistance load
Hold
Hold feature freezes the display for later view. LCD “ ” turns on. Press the HOLD
button momentarily to toggle the hold feature.
Record mode
Press REC button momentarily to activate MAX/MIN/AVG recording mode. LCD “ ” &
“MAX MIN AVG” turn on. The meter beeps when new MAX (maximum) or MIN
(minimum) reading is updated. AVG (Average) reading is calculated over time. Press
the button momentarily to read the MAX, MIN and AVG readings in sequence. Press
the button for 1 second or more to exit this mode. Auto-Power-Off is disabled
automatically in this mode.
Relative-Zero ( ZERO) mode
Relative-Zero allows the user to offset the meter consecutive measurements with the
main display displaying reading as the reference value. LCD “ ” turns on. Press the
ZERO (HOLD) button for one second or more to toggle Relative-Zero mode.
DC-Zero mode is set instead of Relative-Zero mode, however, to only offset the non-
zero DCA residuals caused by magnetic hysteresis of the jaws as in DCA & DC+ACA
functions. Press the ZERO (HOLD) button for one second or more to activate/ re-
activate this mode. Apply this mode before making any single DCA or DC+ACA
measurement for best measuring accuracy. The meter shows “dc_0” shortly to confirm
activation before continuing measurements. The beeper will sound 3 short beeps,
however, to warn for null activation if the residual is beyond a reasonable hysteresis
reading of -5 to 5 DCA.
80ms PEAK-RMS mode
Press PEAK-RMS button for one second or more to toggle PEAK-RMS mode to
capture inrush current or voltage RMS values in duration as short as 80ms. LCD
turns on. Auto-Power-Off is disabled automatically in this mode.
Backlighted LCD display
Press the SELECT button for 1 second or more to toggle the LCD backlight. The
backlight will also be turned off automatically after 32 seconds to extend battery life.

11
Intelligent Auto-Power-Off (APO)
The Auto-Power-off (APO) mode turns the meter off automatically to extend battery life
after approximately 32 minutes of no specified activities, where applicable:
1) Rotary switch or push button operations
2) Significant measuring readings of above 8.5% of ranges
3) Non-OL readings for Resistance, Continuity or Diode function
4) Non-zero readings for Hz function
5) Significant movement indication as in Phase Rotation functions
In other words, the meter will intelligently avoid entering the APO mode when it is
under normal measurements. To wake up the meter from APO, press the SELECT
button momentarily and release, or turn the rotary switch OFF and then back on.
Always turn the rotary switch to the OFF position when the meter is not in use.
5) MAINTENANCE
NOTE
To avoid electrical shock, disconnect the meter from any circuit, remove the test leads
from the input jacks and turn OFF the meter before opening the case. Do not operate
with open case.
Trouble Shooting
If the instrument fails to operate, check batteries and test leads etc., and replace as
necessary. Double check operating procedure as described in this user’s manual.
If the instrument voltage-resistance input terminal has subjected to high voltage
transient (caused by lightning or switching surge to the system under test) by accident
or abnormal conditions of operation, the protective impedance components in series
might be blown off (become high impedance) like open fuses to protect the user and
the instrument. Most measuring functions through this terminal might then be open
circuit. Such components should only be replaced by qualified technician. Refer to the
LIMITED WARRANTY section for obtaining warranty or repairing service.
Accuracy and Calibration
Accuracy is specified for a period of one year after calibration. Periodic calibration at
intervals of one year is recommended to maintain meter accuracy. Refer to the
LIMITED WARRANTY section for obtaining calibration, repairing or warranty service.

12
Cleaning and Storage
Periodically wipe the case with a damp cloth and mild detergent; do not use abrasives
or solvents. If the meter is not to be used for periods of longer than 60 days, remove
the batteries and store them separately.
Battery replacement
The meter uses standard 1.5V AAA Size (IEC R03) battery X 2
Loosen the 2 captive screws from the battery cover case. Lift the battery cover case.
Replace the batteries. Replace battery cover case. Re-fasten the screws.
GENERAL SPECIFICATIONS
Display: 3-5/6 digits 6000 counts.
Polarity: Automatic
Update Rate: 5 per second nominal.
Operating Temperature: 0C to 40C
Relative Humidity: Maximum relative humidity 80% for temperature up to 31C
decreasing linearly to 50% relative humidity at 40C
Pollution degree: 2
Storage Temperature: -20C to 60C, < 80% R.H. (with battery removed)
Altitude: Operating below 2000m
Temperature Coefficient: nominal 0.15 x (specified accuracy)/ C @(0C -- 18C or
28C -- 40C), or otherwise specified

13
Sensing: True RMS
Safety: Certified per IEC/EN/CSA_C22.2_No./UL standards: 61010-1 Ed. 3.1, 61010-
2-032 Ed. 4.0, & 61010-031 Ed. 2.0 to Measurement Categories CAT III 600V and CAT
IV 300V ac & dc
Transient Protection: 6.0kV (1.2/50s surge)
Overload Protections:
Current & Hz functions via jaws: 600ADC/AAC rms at <400Hz
Voltage & 3-Phase Rotation functions via terminals: 660VDC / 920VAC rms
Other functions via terminals: 600VDC/VAC rms
E.M.C.: Meets EN61326-1
DCA and DC+ACA Functions, in an RF field of 1V/m:
Total Accuracy = Specified Accuracy + 20 digits at around 405MHz
DCA and Ohm Functions, in an RF field of 1V/m:
Total Accuracy = Specified Accuracy + 25 digits
Other Functions, in an RF field of 3V/m:
Total Accuracy = Specified Accuracy + 20 digits
Power Supply: 1.5V AAA Size battery X 2
Power Consumption: Typical 13mA for Current functions
Low Battery:
Below approx. 2.85V for Capacitance & Hz
Below approx. 2.5V for other functions
APO Timing: Idle for 32 minutes
APO Consumption: 5A typical
Dimension (LxWxH): 223 x 76 x 37mm
Weight: 234g
Jaw opening & Conductor diameter: 35mm max
Accessories: Test lead set, User's manual, Soft carrying pouch,
Special Features: AmpTipTM low-current range; MAX/MIN/AVG Recording mode;
Display Hold; EF-Detection (NCV); Backlighted LCD; 80ms Peak-RMS mode for inrush
current; Relative-Zero
Electrical Specifications
Accuracy is (% reading digits + number of digits) or otherwise specified, at 23C 
5C.
Maximum Crest Factor < 2.5: 1 at full scale & < 5: 1 at half scale or otherwise specified,
and with frequency spectrum not exceeding the specified frequency bandwidth for non-
sinusoidal waveforms.

14
DC Voltage
RANGE
Accuracy
600.0V
1
.
0
%
+
5d
Input Impedance: 10M, 100 pF nominal
AC Voltage (with Digital Low-Pass Filter)
RANGE
Accu
racy
50Hz ~
60
Hz
600.0V
1
.0
%
+ 5d
Input Impedance: 10M, 100 pF nominal
DC+AC Voltage (with Digital Low-Pass Filter)
RANGE
Accuracy
DC,
50Hz ~
60
Hz
60
0.0V
1.
2
% +
7
d
Input Impedance: 10M, 100 pF nominal
PEAK-rms (ACV & ACA)
Response: 80ms to > 90%
Audible Continuity Tester
Audible Threshold: At between 10 and 250
Response time: 32ms approx.
Ohm
RANGE
Accuracy
600.0

,
6.000K

, 60.00K

1.0% + 5d
Open Circuit Voltage: 1.0VDC typical
Capacitance
RANGE
Accuracy
1)
200
.
0

F,
25
00

F
2.0% + 4d
1)Accuracies with film capacitor or better

15
Diode Tester
RANGE
Accuracy
2
.000V
1.5
% +
5
d
Test Current: 0.3mA typically
Open Circuit Voltage: < 3.5VDC typically
AmpTipTM clamp-on ACA
RANGE
Accuracy
1) 2) 3) 4)
5
0Hz ~
60
Hz
60.00A 1.5% + 5d
1)Induced error from adjacent current-carrying conductor:
<0.01A/A for Models
2)Specified with Relative Zero mode applied to offset the non-zero residual readings,
if any
3)Add 10d to the specified accuracy @ < 4A
AmpTipTM clamp-on DCA
RANG
E
Accuracy
1) 2) 3)
60.00A 2.0% + 5d
1)Induced error from adjacent current-carrying conductor: <0.01A/A
2)Specified with DC-Zero mode applied to offset the non-zero residual readings, if any
3)Add 10d to the specified accuracy @ < 4A
AmpTipTM clamp-on DC+ACA
RANGE
Acc
uracy
1) 2) 3)
DC, 5
0Hz ~
60
Hz
60.00A 2.0% + 7d
1)Induced error from adjacent current-carrying conductor: <0.01A/A
2)Specified with DC-Zero mode applied to offset the non-zero residual readings, if any
3)Add 10d to the specified accuracy @ < 4A

16
Regular Clamp-on ACA
R
ANGE
Accuracy
1) 2) 3)
5
0Hz ~
100
Hz
60.00A
4) 5)
,
600.0A
1.
8
%
+
5
d
100
Hz ~
4
00Hz
60.00
A
4) 5)
,
600.0A
2.0
%
+
5
d
1)Induced error from adjacent current-carrying conductor:
<0.01A/A for Models
2), Maximum Crest Factor < 2: 1 at full scale & < 4 : 1 at half scale
4) add 10d to the specified accuracy @ < 9A
Regular Clamp-on DCA
RANGE
Accuracy
1) 2)
60.00A
3)
,
600.0A
2
.0
%
+
5
d
1)Induced error from adjacent current-carrying conductor: <0.01A/A
2)Specified with DC-Zero mode applied to offset the non-zero residual readings, if any
3)Add 10d to the specified accuracy @ < 9A
Regular Clamp-on DC+ACA
RANGE
Accuracy
1) 2)
DC,
50Hz
~
10
0Hz
60.00A
3)
,
600.0A
2.2
%
+
7
d
10
0Hz ~
40
0Hz
60.00A
3)
,
600.0A
2.7
%
+
7
d
1)Induced error from adjacent current-carrying conductor: < 0.01A/A
2)Specified with DC-Zero mode applied to offset the non-zero residual readings, if any
3)Add 10d to the specified accuracy @ < 9A
Hz Line Level Frequency
Function
Sensitivity
1)
(Sine RMS)
Range
600
V
5
0V
5.00
Hz
~
9
99.9Hz
6
0A (A
mpTip
TM
)
4
0A
50
.00
Hz
~
400
.0
Hz
60A
,
600A
4
0
A
5
0
.00
Hz
~
4
0
0
.0
Hz
Accuracy: 1%+5d
1)DC-bias, if any, not more than 50% of Sine RMS

17
Non-Contact EF-Detection
Typical Voltage
Bar
-
Graph I
ndication
20V (tolerance: 10V
~ 36V
)
-
55V (tolerance: 23V ~ 83V) - -
110
V (tolerance: 59V ~
165
V)
-
-
-
220V
(tolerance:
124
V ~
330
V)
-
-
-
-
440V
(tolerance:
250
V ~
600
V)
-
-
-
-
-
Indication: Bar-graph segments & audible beep tones proportional to the field strength
Detection Frequency: 50/60Hz
Detection Antenna: Inside the top side of the stationary jaw
Probe-Contact EF-Detection: For more precise indication of live wires, such as
distinguishing between live and ground connections, use one single probe to test via
terminal COM for direct contact EF-Detection with best sensitivity.

18
- NOTE -

LIMITED WARRANTY
SEFRAM warrants to the original product purchaser that each product it manufactures
will be free from defects in material and workmanship under normal use and service
within a period of one year from the date of purchase. SEFRAM’s warranty does not
apply to accessories, fuses, fusible resistors, spark gaps, varistors, batteries or any
product which, in SEFRAM's opinion, has been misused, altered, neglected, or
damaged by accident or abnormal conditions of operation or handling.
To obtain warranty service, contact your nearest SEFRAM authorized agent or send
the product, with proof of purchase and description of the difficulty, postage and
insurance prepaid, to SEFRAM INSTRUMENTS. SEFRAM assumes no risk for
damage in transit. SEFRAM will, at its option, repair or replace the defective product
free of charge. However, If SEFRAM determines that the failure was caused by
misused, altered, neglected, or damaged by accident or abnormal conditions of
operation or handling, you will be billed for the repair.
THIS WARRANTY IS EXCLUSIVE AND IS IN LIEU OF ALL OTHER WARRANTIES,
EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED
WARRANTY OR MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
OR USE. SEFRAM WILL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT,
INCIDENTAL OR CONSEQUENTIAL DAMAGES.
SEFRAM
32 Rue Edouard Martel, BP55, 42009
Saint-Etienne - France
04 77 59 01 01
http://www.sefram.com
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