BM120 SERIES
Digital Insulation and Continuity Testers
BM120 Series
Digital Insulation and Continuity Testers
n Tests insulation at rated voltage into a
1 mA load
n 200 mA short circuit continuity current
n Automatic discharge of circuit under test
n Visual warning of energised circuits
above 25 V
n Designed to International Safety
Standards
DESCRIPTION APPLICATIONS
The Megger BM120 Series of Digital Insulation and The BM120 Series will find applications in domestic and
Continuity Testers offers a cost effective solution to testing industrial electrical contracting and in site maintenance
where only basic test facilities are required. departments.
Instruments are available with single insulation test Both instruments may be used on capacitive circuits since,
voltages of 500 V d.c. or 1000 V d.c. and test results are at the end of an insulation test, the circuit under test will
displayed on a clear 3-digit autoranging liquid crystal be automatically discharged through 360 k internal
display. Full rated test voltage is produced when supplying resistance.
up to 1 mA load.
The BM120 Series of Insulation and Continuity Testers are
Both instruments offer hands free continuity measurement ideal for testing transformers, motors, generators,
with a short circuit current of greater than 200 mA and an switchgear, domestic appliances, power tools etc. as well
open circuit voltage of 5 V. as fixed wiring systems.
If either instrument is connected to a system which is Although low cost, both instruments meet the
energised to greater than 25 V, a warning symbol on the requirements of most International Standards including
display will flash. Under this condition an insulation or VDE0413 Part 1, HD384, IEC364 and BS7671 (the 16th
continuity test cannot be carried out and the instrument Edition of the IEE Wiring Regulations).
will therefore automatically inhibit any further action until
This ensures that the rated insulation test voltage can be
the source of voltage has been removed.
achieved into a 1 mA load, ie. 500 V into a 500 k load or
Although insulation tests should only be carried out on 1000 V into a 1 M load.
de-energised systems, the instruments are protected against
FEATURES AND BENEFITS
accidental connection to phase to earth voltages up to
300 V a.c. and phase to phase voltages of 440 V a.c., n Insulation test ranges produce the rated test voltage into
Installation Category III. a 1 mA load. Testing can be carried out to International
Standards requirements.
Further indicators illuminate to show a low battery state
n Single test voltage avoids accidentally overstressing the
and if the protective fuse has ruptured.
insulation of the item under test.
The instruments will automatically shut down after 5
n Clear three digit liquid crystal display produces
minutes of non use.
unambiguous test results.BM120 SERIES
Digital Insulation and Continuity Testers
Auto Shut-Off Storage
n Automatic discharge of capacitive items following an
-25C to +65C
insulation test ensures that circuits are not left The instrument will
automatically switch off after 5 Operating Humidity
dangerously charged.
minutes inactivity. If the 90% RH at 40C maximum
n Continuity range has 0,01 resolution and a short
instrument is not to be used
Power Supply
circuit current in excess of 200 mA to meet the
for several months, it is
6 X 1,5 V cells IEC LR6 type.
requirements of International Standards.
recommended that the
Nickel Cadmium rechargeable
batteries be removed from the
n No need to press the test button when continuity testing
cells may be used.
instrument.
leaves both hands free.
Battery Life Typically more
Fuse
n One button turns instrument on and operates insulation
than 2000 tests each of 5
The instrument is fitted with a
test.
second duration.
500 mA (F) 440 V ceramic 32
n Automatic switch-off after 5 minutes.
Weight
x 6 mm. HBC 10 kA fuse.
530 gm. (1,16 lbs approx.)
Safety
Dimensions
The instrument(s) meet the
195 x 98 x 40 mm. (5 in x 2,4
requirements for double
in x
insulation to IEC 1010-1 (1992),
1 in approx.)
EN 61010-1 (1993) to Category
III, 300 V phase to earth and
Automatic Discharge
SPECIFICATION
440 V phase to phase.
When the test button is
Insulation Ranges
EMC
released after an insulation
Nominal Test
In accordance with IEC61326
test the item under test will be
BM121 BM122
including Amendment No.1
automatically discharged
Voltage (d.c.)
through 360 k internal
Installation Category
500 V 1000 V
resistance.
Category III: Fixed Wiring and
Measuring Range
installations within a building.
Voltage Warning
0,01 M to 999 M
Symbol flashes on the display
Overload Ratings
in the presence of more than
Terminal Voltage on Open
The instrument may be
25 V a.c. or d.c.
Circuit (d.c.) (0 to 30C)
continuously connected to a
-0% +30% of rated voltage
300 V phase to earth, 440 V
phase to phase category III
Continuity Range
Short Circuit Current
supply without damage.
Measuring Range (Auto-
2 mA
ranging)
An overload of 720 V rms. for
Test Current on load
10 seconds will not cause
1mA at minimum pass values
damage to the instrument.
0,01 to 9,99
of insulation as specified in
BS7671, HD384, IEC364 and
Temperature Range
VDE0413 part 1.
Operation
10,0 to 99,9
-20C to +60C up to 100 M
Accuracy (at 20C)
Open Circuit Voltage
3% of reading 2 digits up to
5 V 1 V d.c.
-20C to +40C over full range
10 M
Short Circuit Current
5% of reading 2 digits up to
0,01 to 9,99 210 mA
100 M
ORDERING INFORMATION
30% of reading up to
10,0 to 99,9 21 mA
999 M
Item (Qty) Order No.
Accuracy ( at 20C)
500 V Insulation & Continuity Tester BM121
0,01 to 9,99 3% 2 digits
1300
1200 BM122
1000 V Insulation & Continuity Tester BM122
1100
1000
900
Included Accessories
10,0 to 99,9 5% 2 digits
800
700
Pouch 6420-132
BM121
600
Battery Condition
500
400 Test Lead Set 6220-437
If the battery condition
300
200
becomes low during a test, a Optional Accessories
100
symbol will illuminate on the
0,01M 0,1M 0.5M 1,0M 10M 100M FPK8 Fused Probe Kit 6111-218
Load
display.
Fuses (500 mA) x 5 6121-289
Standard test lead set 6220-437
Terminal Characteristics
Registered to ISO 9001:2000 Reg no. Q 09290
UK UNITED STATES OTHER TECHNICAL SALES OFFICES
Archcliffe Road Dover 4271 Bronze Way Valley Forge USA, Toronto CANADA,
Registered to ISO 14001 Reg no. EMS 61597
CT17 9EN England Dallas TX 75237-1088 USA Mumbai INDIA, Trappes FRANCE,
BM120_DS_en_V10
T +44 (0) 1304 502101 T 800 723 2861 (USA only) Sydney AUSTRALIA, Madrid SPAIN
F +44 (0) 1304 207342 T +1 214 333 3201 and the Kingdom of BAHRAIN.
www.megger.com
F +1 214 331 7399
Megger is a registered trademark
Terminal Voltage