Sealey MM18 User manual

POCKET MULTIMETER
MODEL NO: MM18
Thank you for purchasing a Sealey product. Manufactured to a high standard, this product will, if used according to these instructions,
and properly maintained, give you years of trouble free performance.
IMPORTANT: PLEASE READ THESE INSTRUCTIONS CAREFULLY. NOTE THE SAFE OPERATIONAL REQUIREMENTS, WARNINGS & CAUTIONS. USE
THE PRODUCT CORRECTLY AND WITH CARE FOR THE PURPOSE FOR WHICH IT IS INTENDED. FAILURE TO DO SO MAY CAUSE DAMAGE AND/OR
PERSONAL INJURY AND WILL INVALIDATE THE WARRANTY. KEEP THESE INSTRUCTIONS SAFE FOR FUTURE USE.
1. SAFETY
1.1. PERSONAL PRECAUTIONS
9When using this multimeter, please observe all normal safety rules concerning:
9Protection against the dangers of electrical current.
9Protection of the meter against misuse.
9Full compliance with safety standards can only be guaranteed if used with the test leads supplied. If necessary, they must be replaced
with genuine Sealey leads with the same electrical ratings. Failure to do so will invalidate the warranty.
8DO NOT use leads if damaged or if the wires are bared in any way.
1.2. GENERAL SAFETY INSTRUCTIONS
9Familiarise yourself with the application and limitations of the multimeter as well as the potential hazards.
IF IN ANY DOUBT CONSULT A QUALIFIED ELECTRICIAN.
▲USE EXTREME CAUTION when working with high voltages.
8DO NOT use the meter if it is damaged. Before you use it inspect the case. Pay particular attention to the insulation surrounding the
connectors.
9Inspect the test leads for damaged insulation or exposed metal. Check the test leads for continuity. Replace damaged test leads before
you use the meter.
8DO NOT use the meter if it operates abnormally. Protection may be impaired. When in doubt have the meter inspected by your Sealey
stockist.
8DO NOT operate the meter where explosive gas, vapour or dust is present.
8DO NOT apply more than the rated voltage, as marked on the meter, between the probes or between any probe and earth
ground.
9Before use verify the meter’s operation by measuring a known voltage.
9When measuring current, turn off circuit power before connecting the meter in the circuit. Remember to place the meter in series with the
circuit.
WARNING! Use caution when working with voltage above 30V ac rms, 42V peak, or 60V dc. Such voltages pose a shock hazard.
9When using the probes keep your fingers behind the finger guards.
9When making connections, connect the black test lead before you connect the red test lead. When you disconnect the test leads,
disconnect the red one first.
9Remove the test leads from the circuit under test before you open the back cover.
8DO NOT operate the meter with the back cover removed or loosened.
9To avoid false readings, which could lead to possible electric shock or personal injury, replace the button cells as soon as the low battery
indicator ( ) appears.
8DO NOT touch any naked conductor with your hand or skin, to avoid electric shock, DO NOT ground yourself whilst using the meter.
9When a probe is connected to a dangerous live potential, it must be noted that this potential can occur at the other probe.
NOTE: CAT II measurement category is for measurements performed on circuits directly connected to low voltage installations.
(Examples are measurements on household appliances, portable tools and similar equipment.) DO NOT use the meter for measurements
within Measurement Categories III and IV.
9Disconnect circuit power and discharge all capacitors before testing resistance, diode or continuity.
9Use the proper function for your measurements.
9Before measuring current, check the meter’s fuse and turn off power to the circuit before connecting the meter to the circuit.
9Before moving the function switch or rotating the range switch, disconnect the test leads from the circuit under test.
9The user shall ensure that test probes are correctly selected in order to prevent danger. Probes shall be selected to ensure that adequate
barriers guard against inadvertent hand contact with live conductors under test and that probes have minimal exposed probe tips. Where
there is a risk of the probe tip short circuiting with other live conductors under test, it is recommended that the exposed tip length shall not
exceed 4mm.
NOTE:The warnings, cautions and instructions referred to in this manual cannot cover all possible conditions and situations that may
occur. It must be understood that common sense and caution are factors which cannot be built into this product, but must be applied
by the operator.
S
Refer to
instruction
manual
Warning!
Electricity
Original Language Version
© Jack Sealey Limited MM18 | Issue:3 (H,F) 07/12/18

Original Language Version
© Jack Sealey Limited
1.3. ELECTRICAL SYMBOLS
2. INTRODUCTION
Handy compact unit, small enough to fit in your pocket, making it ideal for basic circuit testing whilst on the move. Features flip lid for added screen
protection and storage of leads. Conforms to EN 61010-1 CAT II safety requirements. Supplied with test leads. Measures: AC and DC Voltage,
DC Current, Resistance, Audible Continuity
3. FEATURES
4. SPECIFICATION
Model No:..................................................................... MM18
Measures:
Voltage DC:.............................. 2V, 20V, 200V, 250V (±1.0%)
Voltage AC: ...................................................... 250V (±1.2%)
Current DC:....................................................200mA (±1.2%)
Resistance: ............... 2k Ω, 20k Ω, 200k Ω, 2000k Ω (±1.2%)
Continuity Audible: ........................................................... Yes
Digits x Height:.......................................................5 x 11mm
Batteries (Supplied):..................................................2 x 1.5V
Size (L x W x H): ......................................... 114 x 56 x 23mm
Weight:........................................................................... 101g
Conformity:.......................................................... EN 61010-1
Operation Environment: ...................................... 0°C to 40°C
Relative Humidity: .........................................................<75%
Storage Temperature: ...................................... -10°C to 50°C
Relative Humidity: .........................................................<85%
Alternating Current.
Direct Current.
Both direct and alternating current.
Caution risk of danger refer to operating
manual before use.
Caution risk of electric shock.
Earth (ground) terminal.
Fuse.
The equipment is protected throughout by double insulation or
reinforced insulation.
1. Display: 3½ digit LCD, with a max. reading of 1999.
2. Function selector.
3. Range Switch: used to select desired range.
4. Test Probes
RESISTANCE
Range Resolution Accuracy
2kΩ 0.001kΩ
± (1.2% + 5 digits)
20kΩ 0.01kΩ
200kΩ 0.1kΩ
2000kΩ 1kΩ
Max open circuit voltage: About 0.4V
Overload protection: 250V DC/AC rms
AC VOLTAGE
Range Resolution Accuracy
200V 0.1V
± (1.2% + 10 digits)
250V 1V
Input Impedance:500kΩ
Frequency range: 40Hz to 400Hz
Max. Allowable Input Voltage: 250V ac rms
Response: Average, calibrated in rms of sine wave.
DC CURRENT
Range Resolution Accuracy
200mA 0.1mA ± (1.2% + 5 digits)
Overload protection: 250mA/250AV Fast fuse
DC VOLTAGE
Range Resolution Accuracy
2V 0.001V
±(1.0% +5 digits)
20V 0.01V
200V 0.1V
250V 1V
Input Impedance: 1MΩ
Max Allowable Input Voltage: 250V dc
MM18 | Issue:3 (H,F) 07/12/18
DIODE AND CONTINUITY
Range Description Remark
The display shows the approximate forward voltage drop of the diode. Open circuit voltage about 2.5V
Max test current: 1mA
The built in buzzer will sound if the resistance is less than about 30Ω.
The buzzer may not sound if the resistance is between 30Ω and 100Ω.
The buzzer will not sound if the resistance is more than 100Ω. Open circuit voltage about 2.5V.
Overload protection: 250V DC/AC rms

4.1. MEASURING DC VOLTAGE
4.1.1. Set the function switch to the V position.
4.1.2. Set the range to the desired position. If the magnitude of the voltage to be measured is not known beforehand, set the range switch to
the highest range rst and then reduce it range by range until satisfactory resolution is obtained.
4.1.3. Connect the test leads across the source or circuit to be tested.
4.1.4. Read the display. The polarity of the red test lead connection will be indicated as well.
NOTE: To avoid electric shock to you or damage to the meter, DO NOT measure a voltage higher than 250V.
4.2. MEASURING AC VOLTAGE
4.2.1. Set the function switch to the V~position.
4.2.2. Set the range switch to 250V or 200V range position.
4.2.3. If the magnitude of the voltage to be measured is not known beforehand, set the range to the highest rst and then reduce it until a
satisfactory resolution is obtained.
4.2.4. Read the display.
NOTE: To avoid electric shock to you or damage to the meter, DO NOT measure a voltage higher than 250V.
4.3. MEASURING DC CURRENT
4.3.1. Set the function switch to A position.
4.3.2. Set the range switch to the 200mA range position.
4.3.3. Turn off the circuit to be tested. Then discharge all capacitors.
4.3.4. Break the circuit path to be tested, then connect the test leads in series with the circuit.
4.3.5. Turn on the power to the circuit, then read the display. The polarity of the red test lead connection will be indicated as well.
4.4. MEASURING RESISTANCE
4.4.1. Set the function switch to position.
4.4.2. Set the range switch to the desired resistance measuring range position.
4.4.3. Connect the test leads across the object to be measured.
4.4.4. Read the reading on the display.
NOTE:
1. For measurements > 1MΩ, the meter may take a few seconds to stabilise a reading. This is normal for high resistance
measurements.
2. When the test leads are in open circuit state , “1” will be displayed as an over-range indication.
3. Before measurement, disconnect all power to the circuit to be tested and discharge all capacitors thoroughly.
4.5. DIODE TEST
4.5.1. Set the function to the position.
4.5.2. Set the range switch to the position.
4.5.3. Connect the red test lead to the anode of the diode to be tested and the black lead to the cathode of the diode.
4.5.4. The display shows the approximate forward voltage drop of the diode. If the connection is reversed, “1” will be shown on the display.
4.6. CONTINUITY TEST
4.6.1. Set the function switch to the position.
4.6.2. Set the range switch to the position.
4.6.3. Connect the test leads across the circuit to be tested.
4.6.4. If the resistance is less than about 30Ω, the built in buzzer will sound.
NOTE: Before test, disconnect all power to the circuit to be tested and discharge all capacitors thoroughly.
5. MAINTENANCE
5.1. CLEANING
5.1.1. Wipe the case clean with a damp cloth and mild detergent.
8DO NOT use abrasives or solvents.
5.2. BATTERY REPLACEMENT
5.2.1. When symbol appears on the display, the batteries are low and need to be replaced immediately.
WARNING! Remove all leads from the circuit under test before opening back cover.
5.2.2. Remove the screws securing the back cover, refer to g.1. below.
5.2.3. Replace the batteries (1.5V button cell LR44 or equivalent). Make sure the polarity connections are correct (refer to indication on the
bottom of each cell compartment).
5.2.4. Refit back cover.
5.3. FUSE
5.3.1. The fuse rarely needs to be replaced and will blow as a result of operator error.
WARNING! Remove all leads from the circuit under test before opening back cover.
5.3.2. Remove screws securing back cover, refer to fig.1, and replace with 250mA/250V, fast, Ø5 x 20mm fuse.
Original Language Version
© Jack Sealey Limited MM18 | Issue:3 (H,F) 07/12/18

Sealey Group, Kempson Way, Suffolk Business Park, Bury St Edmunds, Suffolk. IP32 7AR
01284 757500 01284 703534 [e-mail] www.sealey.co.uk
ENVIRONMENT PROTECTION
Recycle unwanted materials instead of disposing of them as waste. All tools, accessories and packaging should be sorted, taken to
a recycling centre and disposed of in a manner which is compatible with the environment. When the product becomes completely
unserviceable and requires disposal, drain any fluids (if applicable) into approved containers and dispose of the product and fluids
according to local regulations.
Note: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior
notice.
Important: No Liability is accepted for incorrect use of this product.
Warranty: Guarantee is 12 months from purchase date, proof of which is required for any claim.
WEEE REGULATIONS
Dispose of this product at the end of its working life in compliance with the EU Directive on Waste Electrical and Electronic Equipment
(WEEE). When the product is no longer required, it must be disposed of in an environmentally protective way. Contact your local solid
waste authority for recycling information.
Original Language Version
© Jack Sealey Limited MM18 | Issue:3 (H,F) 07/12/18
BATTERY REMOVAL REFER TO SECTION 6.2
Under the Waste Batteries and Accumulators Regulations 2009, Jack Sealey Ltd are required to inform potential purchasers of products
containing batteries (as defined within these regulations), that they are registered with Valpak’s registered compliance scheme. Jack
Sealey Ltd Batteries Producer Registration Number (BPRN) is BPRN00705.
fig.1