Klein Tools MM400 Digital Multimeter Instruction Manual

: June 1, 2024
: KLEIN TOOLS

Table of Contents

Klein Tools MM400 Digital Multimeter
GENERAL SPECIFICATIONS
FEATURE DETAILS
FUNCTION BUTTONS
OPERATING INSTRUCTIONS
MAINTENANCE
CUSTOMER SERVICE
FREQUENTLY ASKED QUESTIONS
VIDEO – PRODUCT OVERVIEW
Read User Manual Online (PDF format)
Download This Manual (PDF format)

Klein Tools MM400 Digital Multimeter

Klein-Tools-MM400-Digital-Multimeter-product

GENERAL SPECIFICATIONS

Klein Tools MM400 is an auto-ranging multimeter that measures AC/DC voltage, AC/DC current, and resistance. It can also measure temperature, capacitance, frequency, duty cycle, and test diodes and continuity.

Operating Altitude: 6562 ft. (2000m)
Relative Humidity: <80% non-condensing
Operating Temp: 32°F to 104°F (0°C to 40°C)
Storage Temp: 14°F to 140°F (-10°C to 60°C)
Accuracy: Values stated at 65°F to 83°F (18°C to 28°C)
Temp Coefficient: 0.1 x (Quoted Accuracy) per °C above 28°C or below 18°C, corrections are required when the ambient working temp is outside of the Accuracy Temp range
Dimensions: 6.04″ x 3.07″ x 1.78″ (153.4 x 78.0 x 45.2 mm)
Weight: 8.1 oz. (230 g)
Calibration: Accurate for one year
Standards: Conforms to: UL STD 61010-1, 61010-2-030, 61010-2-033.
Certified to: CSA STD C22.2 # 61010-1, 61010-2-030, 61010-2-033.
- IEC EN 61010-1, 61010-2-030, 61010-2-033, 61326-1.
Pollution degree: 2
Accuracy: ± (% of reading + # of least significant digits)
Drop Protection: 3.3 ft. (1m)
Safety Rating: CAT III 600V, Class 2, Double insulation
CAT III: Measurement category III is applicable to test and measuring circuits connected to the distribution part of the building’s low-voltage MAINS installation.
Electromagnetic Environment: IEC EN 61326-1. This equipment meets requirements for use in basic and controlled electromagnetic environments like residential properties, business premises, and light-industrial locations.

Specifications subject to change

ELECTRICAL SPECIFICATIONS

VOLTAGE (AUTO-RANGING)

Function	Range	Resolution	Accuracy

AC Voltage (V AC)

| 4.000V| 1mV| ±(1.2% + 5 digits)
40.00V| 10mV| ±(1.5% + 5 digits)
400.0V| 100mV
600V| 1V| ±(2.0% + 5 digits)

DC Voltage (V DC)

| 400.0mV| 0.1mV| ±(1.0% + 8 digits)
4.000V| 1mV|

±(1.2% + 3 digits)

40.00V| 10mV
400.0V| 100mV
600V| 1V| ±(1.5% + 3 digits)

Input Impedance: 10MΩ
Frequency Range: 50 to 60Hz
Maximum Input: 600V AC RMS or 600V DC

CURRENT (AUTO-RANGING)

AC Current (µA and mA)

| 400.0µA| 0.1µA| ±(1.5% + 5 digits)
---|---|---|---
4000µA| 1µA| ****

±(1.8% + 5 digits)

40.00mA| 10µA
400.0mA| 100µA
10A| 10mA| ±(3.0% + 7 digits)

DC Current (µA and mA)

| 400.0µA| 0.1µA| ±(1.0% + 5 digits)
4000µA| 1µA| ****

±(1.5% + 5 digits)

40.00mA| 10µA
400.0mA| 100µA
10A| 10mA| ±(3.0% + 7 digits)

Overload Protection: 500mA / 600V and 10A / 600V Fuses
Frequency Range : 50 to 60Hz
Maximum Input: µA/mA
setting: 500mA AC RMS / DC
10A setting: 10A AC RMS / DC

RESISTANCE (AUTO-RANGING)

Range	Resolution	Accuracy
400.0O	0.1O	****

±(1.5% + 5 digits)

4.000kO| 1O
40.00kO| 10O
400.0kO| 100O
4.000MO| 1kO| ±(2.0% + 10 digits)
40.00MO| 10kO

Maximum Input: 600V DC or 600V AC RMS

CAPACITANCE (AUTO-RANGING)

Range	Resolution	Accuracy
40.00nF	10pF	±(5.0% + 35 digits)
400.0nF	0.1nF	****

±(3.0% + 5 digits)

4.000µF| 1nF
40.00µF| 10nF
200.0µF| 0.1µF| ±(5.0% + 5 digits)

Maximum Input: 600V DC or 600V AC RMS

FREQUENCY (AUTO-RANGING)

9.999Hz	0.001Hz	±(1.5% + 5 digits)
99.99Hz	0.01Hz
999.9Hz	0.1Hz	****

±(1.3% + 5 digits)

9.999kHz| 1Hz
50.00kHz| 10Hz

Sensitivity: >8V RMS
Maximum Input: 600V DC or 600V AC RMS

DUTY CYCLE

0.1% to 99.9%	0.1%	±(1.2% + 2 digits)

Pulse width: >100us, <100ms
Frequency width: 5Hz to 10kHz
Sensitivity: >8V RMS
Maximum Input: 600V DC or 600V AC RMS

TEMPERATURE

0 ° to 1000 ° F	0.1°F / 1.0°F	±(3.0% + 9°F)
-18° to 538°C	0.1°C / 1.0°C	±(3.0% + 5°C)

Diode Test: 1.5 mA max, open circuit voltage 3.0V DC
Continuity Check: Audible signal <50Ω
Sampling Frequency: 3 samples per second
Overload: “OL” indicated on display, overload protection 600V RMS in all settings
Polarity: “-” on display indicates negative polarity
Display: 3 ¾ digit, 4000 Count LCD

WARNINGS

To ensure safe operation and service of the meter, follow these instructions. Failure to observe these warnings can result in severe injury or death.

Before each use verify meter operation by measuring a known voltage or current.
Never use the meter on a circuit with voltages that exceed the category based rating of this meter.
Do not use the meter during electrical storms or in wet weather.
Do not use the meter or test leads if they appear to be damaged.
Use only with CAT III or CAT IV rated test leads.
Ensure meter leads are fully seated, and keep fingers away from the metal probe contacts when making measurements.
Do not open the meter to replace batteries while the probes are connected.
Use caution when working with voltages above 25V AC RMS or 60V DC. Such voltages pose a shock hazard.
To avoid false readings that can lead to electrical shock, replace batteries when a low battery indicator appears.
Do not attempt to measure resistance or continuity on a live circuit.
Always adhere to local and national safety codes. Use personal protective equipment to prevent shock and arc blast injury where hazardous live conductors are exposed.

SYMBOLS ON METER

$Klein-Tools-MM400-Digital-Multimeter-fig- $1$$

Warning or Caution
To ensure safe operation and service of this meter, follow all warnings and instructions detailed in this manual.
Risk of Electrical Shock
Improper use of this meter can lead to risk of electrical shock. Follow all warnings and instructions detailed in this manual.

SYMBOLS ON LCD

$Klein-Tools-MM400-Digital-Multimeter-fig- $4$$

FEATURE DETAILS

NOTE: There are no user-serviceable parts inside meter.

4000 count LCD display
Function selector switch
“10A” jack
“COM” jack
“VΩ” jack
Backlight ON/OFF button
“RANGE” button
“MAX/MIN” button
“HOLD” (Data Hold) button
“SEL” (Select) button

FUNCTION BUTTONS

ON/OFF
To Power ON the meter rotate the Function Selector switch 2 from the OFF setting to any measurement setting. To Power OFF the meter rotate the Function Selector switch 2 to the OFF setting. By default, the meter will automatically Power OFF after 30 minutes of inactivity. Reactivate meter by pressing any button. To deactivate the automatic Power OFF feature, power the meter ON with the SEL button 11 depressed. When automatic Power OFF is deactivated, the symbol will not be visible in the display.
“SEL” (SELECT) BUTTON (FOR SECONDARY FUNCTIONS)
The “SEL” button 10 activates the secondary function for each application accessible by the function selector switch 2 . For current and voltage, it toggles between AC and DC. For the other functions, it switches between °F and °C, between Hz and % Duty-cycle, between Continuity and Resistance, and between Capacitance and Diode-test. The default function for each application is printed on the meter in white; the secondary function for each location is printed on the meter in orange.
“HOLD” (DATA HOLD) BUTTON
Press the “HOLD” button 9 to hold the measurement on the display. Press again to release the display and return to live measuring.
“RANGE” BUTTON
The meter defaults to auto-ranging measurement mode . This automatically determines the most appropriate measurement range for the testing that is being conducted. To manually force the meter to measure in a different range, use the “RANGE” button 7 .
- Press the “RANGE” button 7 to manually select measurement range ( is deactivated on the LCD). Repeatedly press the “RANGE” button 7 to cycle through the available ranges, stopping once the desired range is reached.
- To return to auto-ranging mode, press and hold the “RANGE” button 7 for more than one second ( is reactivated).
“MAX/MIN” BUTTON
When the “MAX/MIN” button 8 is pressed, the meter keeps track of the minimum and maximum value of the measurement as the meter continues to take samples. The first press of the “MAX/MIN” button 8 displays the Max value, the second press displays the Min value. To return to normal measuring mode, press and hold the “MAX/MIN” button 8 for more than one second.
BACKLIGHT BUTTON
Press and hold the backlight button 6 for more than one second to turn the backlight on or off. Backlight automatically turns off after approximately 3 minutes.

OPERATING INSTRUCTIONS

CONNECTING TEST LEADS
Do not test if leads are improperly seated. Results could cause intermittent display readings. To ensure proper connection, firmly press leads into the input jack completely. $Klein-Tools-MM400-Digital-Multimeter-fig- $8$$
TESTING IN CAT III / CAT IV MEASUREMENT LOCATIONS
Ensure the test lead shield is pressed firmly in place. Failure to use the CAT III / CAT IV shield increases arc-flash risk. $Klein-Tools-MM400-Digital- Multimeter-fig- $9$$
TESTING IN CAT II MEASUREMENT LOCATIONS
CAT III / CAT IV shields may be removed for CAT II locations. This will allow testing on recessed conductors such as standard wall outlets. Take care not to lose the shields. $Klein-Tools-MM400-Digital-Multimeter-fig- $10$$

AC/DC VOLTAGE (LESS THAN 600V)

Insert RED test lead into V jack 5 , and BLACK test lead into COM jack 4 , and rotate function selector switch 2 the setting.
NOTE: The meter defaults to AC measurement. Press the “SEL” button 10 to toggle between AC and DC modes. The AC or DC icon on the LCD indicates which mode is selected. $Klein-Tools-MM400-Digital-Multimeter-fig- $15$$
Apply test leads to the circuit to be tested to measure voltage. The meter will auto-range to display the measurement in the most appropriate range.

NOTE: If “–” appears on the LCD, the test leads are being applied to the circuit in reverse polarity. Swap the position of the leads to correct this.

NOTE: When in a voltage setting and the test leads are open, readings of order mV may appear on the display. This is noise and is normal. By touching the test leads together to close the circuit the meter will measure zero volts.

AC/DC CURRENT

NOTE: The meter defaults to AC measurement. Press the “SEL” button 10 to toggle between AC and DC modes. The AC or DC icon on the LCD indicates which mode is selected.

Attach test leads to the appropriate jacks and rotate function selector switch 2 to the appropriate setting as follows:
- For AC/DC currents >400mA and <10A: Insert RED test lead into 10A jack 3 , and BLACK test lead into COM jack 4 , and rotate function selector switch 2 to the 10A AC/DC setting. $Klein-Tools-MM400-Digital-Multimeter-fig- $15$$
- For mA AC/DC currents <400mA: Insert RED test lead into V jack 5 , and BLACK test lead into COM jack 4 , and rotate function selector switch 2 to the mA AC/DC setting. $Klein-Tools-MM400-Digital-Multimeter-fig- $15$$
- For μA DC currents <400μA: Insert RED test lead into V jack 5 , and BLACK test lead into COM jack 4 , and rotate function selector switch 2 to the μA AC/DC setting. $Klein-Tools-MM400-Digital-Multimeter-fig- $15$$
To measure current: Remove power from circuit, open circuit at measurement point, connect meter in-series in the circuit using the test leads, and apply power to circuit.
Measure the current. The meter will auto-range to display the measurement in the most appropriate range.

Do not attempt to measure more than 10A.

When measuring currents greater than 6A, a measurement time of 30 seconds followed by 10 minutes of recovery time is recommended.

RESISTANCE MEASUREMENTS

Insert RED test lead into V jack 5 , and BLACK test lead into COM jack 4 , and rotate function selector switch 2 to the Continuity/Resistance setting.
NOTE: The meter defaults to Continuity testing in this mode. To enter Resistance testing mode, press the “SEL” button 10 once. The Resistance icon will appear on the display.
Remove power from circuit.
Measure resistance by connecting test leads to circuit. The meter will auto-range to display the measurement in the most appropriate range.