FNIRSI MC-40 Smart Digital Clamp Meter

Overview

This digital AC clamp meter is a stable, safe, and reliable instrument. It is designed with a micro smart IC and a dual integral A/D converter as its core, featuring a full-range overload protection circuit. Its modern appearance makes it suitable for measuring AC current, AC/DC voltage, resistance, diodes, and performing circuit continuity tests, making it an excellent tool for electricians.

Safety Information

Safety Standards

This instrument has been designed and manufactured in accordance with the safety standards for electronic measuring instruments and handheld current clamp meters: IEC61010-1, IEC61010-2-032. It complies with dual insulation, CAT III 600V, and pollution class 2 safety standards.

Safety Symbols

• ⚠️ Warning symbol: Operate with caution.
• ❗ High voltage danger symbol.
• ⚡ Allow use near conductors that are not dangerous to life.
• ?️ Dual insulation (Class II safety equipment).
• ? Ground.

Notice

Read this instruction manual carefully before using the instrument, paying special attention to the contents marked with ⚠️ symbols. Follow the operating instructions associated with these symbols.

If the test pen needs replacement, it must be replaced with the same model number or one with identical electrical specifications.

Accessories and Precautions

Included Accessories

• Instruction Manual: 1 pc
• Test Lead: 1 pair
• Package Box: 1 pc
• 1.5V AAA Batteries: 2 pcs

Before Use Precautions

• Check the instrument and test pens before use. Do not use if test pens are exposed, the casing is damaged, or the display is abnormal.
• During measurement, do not touch unused input terminals.
• When measuring voltage higher than 60V DC or 30V AC, be cautious and ensure your fingers do not go beyond the safety barrier on the test pen.
• If the measurement range is unknown, set the function and range selector to the maximum range position.
• Do not exceed the input limit for each range.
• Do not measure voltage higher than the allowable input value.
• Before switching function and range, the test leads should be removed from the circuit being tested.
• Before measuring resistance in a live circuit, disconnect the power and fully discharge all capacitors.
• Do not expose the instrument to strong light, high temperatures, or damp environments.
• Do not touch bare wires, connectors, or circuits being measured with bare hands.

Panel Description

The FNIRSI MC-40 clamp meter features the following components:

1. Jaw Assembly: Used for sampling AC current.
2. Safety Barrier: Prevents accidental contact with live conductors during measurement.
3. Rotary Range Selector: Used to select measurement functions and ranges.
4. HOLD Button (?️): Press to hold the last reading on the display, indicated by the "H" symbol. Press again to resume normal measurement.
5. Backlight Button: Press and hold for 2 seconds to turn the display backlight on. Press and hold for 2 seconds again to turn it off.
6. LCD Display: Maximum display of 4000, with a character height of 12mm.
7. INPUT Terminal: Red test lead positive input terminal for voltage, resistance, diode, and continuity tests.
8. COM Terminal: Black test lead negative input terminal (except for AC current measurement).
9. Flashlight Button: Press to turn on the flashlight; press again to turn it off.
10. SEL Button: In measurement modes, used to switch between resistance, diode, and continuity tests.
11. Warning Light: Illuminates red during continuity, NCV, or high voltage alerts.
12. Lever for Jaw Opening/Closing: Press to open the jaws; release to close them automatically.
13. CAT III 600V Label: Indicates the safety category and voltage rating.
14. NCV Sensor Probe: When a strong AC signal is detected, a red indicator light turns on, accompanied by rapid beeping sounds.

Operating Instructions

AC and DC Voltage Measurement

Insert the red test lead into the ? INPUT jack and the black test lead into the ? COM jack.

A. DC Voltage Measurement: Turn the rotary range selector to the ⚡ (V) range. Connect the test leads to the voltage source to be measured. The polarity of the red test lead will be displayed. Read the measurement result from the display.

B. AC Voltage Measurement: Turn the rotary range selector to the ⚡ (V~) range. Connect the test leads to the voltage source to be measured. Read the measurement result from the display.

Caution: If the voltage range is unknown, set the selector to the maximum range and gradually decrease it to obtain satisfactory resolution. Be extremely careful when measuring high voltages to avoid electric shock.

AC Current Measurement

1. Turn the rotary range selector to the AC current measurement position.
2. Clamp the jaw around a single conductor to measure the current flowing through it. Do not clamp around multiple conductors simultaneously.
3. Read the measurement result from the display.

Notice: If the current range is unknown, set the selector to the maximum current range and gradually decrease it to obtain satisfactory resolution.

Resistance Measurement

1. Insert the red and black test leads into the ? INPUT and ? COM jacks, respectively.
2. Turn the rotary range selector to the Ω resistance range, then press the SEL button to switch to the Ω mode. Connect the test probes to the component to be measured.
3. Read the measurement result from the display.

Notice:

• If the measured resistance exceeds the maximum value of the selected range, the display will show "OL" [Overload]. Select a higher range.
• When checking resistance in a live circuit, ensure the power is turned off and all capacitors are fully discharged.
• Measuring resistances above 1MΩ may require a few seconds for the reading to stabilize. This is normal for high resistance measurements.

Diode and Continuity Test

Insert the red test lead into the ? INPUT jack and the black test lead into the ? COM jack. The polarity of the red test lead is "+".

1. Diode Test: Turn the rotary range selector to the diode mode (➡️), then press the SEL button to switch to the diode test range. Connect the red test lead to the anode and the black test lead to the cathode of the diode. Read the approximate forward voltage drop from the display.
2. Continuity Test: Turn the rotary range selector to the continuity mode (?), then press the SEL button to switch to the continuity test range. Connect the test leads to the two points of the circuit. If the built-in beeper sounds (?), it indicates that the resistance between these two points is less than or equal to 50Ω.

Auto Off

To extend battery life, this instrument features an automatic power-off function. If no key operation or range change is performed for approximately 25 minutes, the instrument will automatically shut down.

Specifications

Accuracy

General Accuracy: ± (a% reading + cts)

Warranty: 1 year from the date of manufacture.

Environmental Conditions: Operating Temperature: 18°C~28°C; Ambient Humidity: Not greater than 75%.

Temperature Coefficient: 0.1 × accuracy / 1°C

Notice for AC Current Measurement: When measuring AC current, place the conductor in the center of the jaw. If not centered, it may introduce an error of up to 1.5%.

DC Voltage

Input Resistance: 10MΩ.

Max. Input Voltage: 600V DC or 600V AC RMS.

AC Voltage

Input Resistance: 10MΩ.

Frequency Range: 40Hz~400Hz.

Max. Input Voltage: 600V DC or 600V AC RMS.

AC Current

Frequency Range: 50Hz~60Hz.

Max. Input Current: 120% of full scale, for less than 60 seconds.

Resistance

Overload Protection: 600V DC or 600V AC RMS.

Diode Test

Overload Protection: 600V DC or 600V AC RMS.

Continuity Test

Overload Protection: 600V DC or 600V AC RMS.

Technical Specifications

• General: Max. Voltage between input and ground is CAT II 600V DC and 600V AC.
• Display: LCD, max reading 4000.
• Principle: Dual Integral A/D transformer, auto range.
• Measuring Frequency: 3 times/second.
• Unit Display: Displays function and unit symbols.
• Electrode: Negative input shows "-".
• Overload Display: "OL".
• Data Hold Display: "?️".
• Low Power Display: "?".
• Power Supply: DC1.5V x 2 Size AAA.
• Dimension: 185mm x 71mm x 35mm.
• Max. Jaw Opening Size: 26mm.
• Temperature Environment for Use: 5°C~35°C.
• Temperature for Storing: -10°C~50°C.

Maintenance and Battery Replacement

Maintenance

1. Before opening the back cover, disconnect the test leads from the measured circuit.
2. Clean the instrument using a damp cloth and a small amount of detergent. Do not use chemical solvents or abrasive cleaners.
3. Stop using the instrument immediately if any abnormal conditions occur and send it for repair.
4. Calibration or maintenance should only be performed by qualified professionals.

Battery Replacement

Warning: To avoid electric shock, disconnect test leads from the measured circuit before opening the battery cover. Only replace batteries with the same type and electrical specifications.

When the "?" low power icon appears, the batteries need to be replaced immediately. Follow these steps:

1. Take away test leads from the measured circuit. Turn the rotary range selector to "? OFF". Remove leads from input jacks.
2. Use a screwdriver to unscrew and remove the battery cover.
3. Take out the used batteries and replace them with two new 1.5V AAA batteries.
4. Replace the cover and tighten the screws securely.

Product Information

Product Name: Smart Digital Clamp Meter

Brand/Model: MC-40

Service Phone: 0755-28020752

Manufacturer: Shenzhen FNIRSI Technology Co., Ltd.

Website: www.fnirsi.cn

Address: 8th Floor, Building C, Weida Industrial Park, Dalang Street, Longhua District, Shenzhen, Guangdong Province, China.

Execution Standard: GB/T 32194-2015

For any questions, please contact FNIRSI. The company promises a satisfactory solution and offers an additional 6-month warranty as a token of appreciation. You are welcome to join the FNIRSI community.