Yokogawa MY40-01
Digital Insulation Resistance Tester, 1000V Max Test Voltage

  • Selectable Test Voltages: 125V, 250V, 500V, 1000V
  • Insulation resistance: AC voltage and conductor resistance measurement
  • Insulation test mode: Comparator, memory, auto-hold and discharge function
  • All test modes: Live-line alarm (Exchange AC voltage measurement)
  • Easy to view, function-free display
  • Double-action safety mechanism
  • Includes Hard Carrying Case (93015) and Accessory Bag (B9108XA)
Click for larger image of the Yokogawa MY40-01 Digital Insulation Resistance Tester, 1000V Max Test VoltageClick for larger image
Yokogawa MY40-01 Shown
Product Information
Datasheet 163 KB PDF
Manual 343 KB PDF
PDF HelpPDF Help

4 ratings, Digital type Rating: 125V/200Megohm, 250V/200Megohm, 500V/2000Megohm, 1000V/2000Megohm Features: Automatic discharge function, Live-line alarm, Comparator, Internal memory, AC Voltage measurement


3 1/2-digit LCD; 4000 count; backlight-illuminated; logarithmic bar graph; extension bar graph–no fluctuations, as the display shows the digits of a reading in the order in which each digit settles.

Comparator function:

The MY40 alerts you by turning on the LOW symbol and sounding the buzzer if the measured value is smaller than the reference value. You can allocate as many as three user-defined reference values to each rating. The factory-set defaults are 0.1 MΩ, 0.2 MΩ and 0.4 MΩ.

Memory function:

For each rating, you can save as many as 20 measurements at desired memory address numbers.

Automatic discharge function:

The MY40 automatically begins discharge when you turn off the MEAS switch. You can monitor the state of discharge by checking the bar graph and make sure discharge is complete by checking that the segment bar disappear.

High-voltage indicators:

The high-voltage symbol and LED lamp come on to alert you when the MY40 is in insulation testing mode or if any voltage remains to be discharged.

Live-line alarm:

If you apply an AC voltage of approximately 40 V or higher across the input terminals, the MY40 alerts you by blinking the LED lamp and sounding the buzzer.

Over range input alarm:

If the voltage being measured exceeds 600 V during AC voltage measurement, the MY40 alerts you by flashing the Maximum Value indicator and sounding the buzzer.

Auto-hold function:

The tester retains the measured resistance for approximately 5 seconds after the MEAS switch is turned off.


25(W)x103(H)x53(D)mm, excluding protrusions


420 g (main unit and batteries only, excluding accessories)

Rating Range Option Resolution Measuring Range Tolerance Lower Limit of measured Ω Rated Current Central Scale Value
125V/200MΩ .4000 4.000 40.00 200.0 .1kΩ 1 kΩ 10kΩ 100kΩ 0-.0199MΩ .0200-10.00MΩ 10.01-200.0MΩ
±(5% 0f rdg+6dgt) ±(2% of rdg+6dgt) ±5% of rdg
0.125MΩ 1mA 5MΩ
250V/200MΩ .4000 4.000 40.00 200.0 .1kΩ 1 kΩ 10kΩ 100kΩ 0-.0499MΩ .0500-20.00MΩ 20.01-200.0
±(5% 0f rdg+6dgt) ±(2% of rdg+6dgt) ±5% of rdg
0.25MΩ 1mA 5MΩ
500V/2000MΩ 4.000 40.00 400.0 2000 1 k 10kΩ 100kΩ 1 MΩ 0-0.999MΩ 1.000-500MΩ 501-2000MΩ
±(5% 0f rdg+6dgt) ±(2% of rdg+6dgt) ±5% of rdg
0.5MΩ 1mA 50MΩ
100V/2000MΩ 4.000 40.00 400.0 2000 1 kΩ 10kΩ 100kΩ 1 MΩ 0-1.999MΩ 2.000-1000MΩ 1001-2000MΩ
±(5% 0f rdg+6dgt) ±(2% of rdg+6dgt) ±5% of rdg
2MΩ 0.5mA 50MΩ
Ordering Information
Model Description Buy Now Price
MY40-01 Yokogawa MY40-01 Digital Insulation Resistance Tester, 1000V Max Test Voltage Buy Now Sale $600.10
(Reg. $706.00)
Included Accessories
  • 4 - Batteries
  • 1 - Earth probe (98002)
  • 1 - Line Probe (98001)
  • 1 - Protective cover (93013)
  • 1 - Shoulder strap (99005)
  • 1 - Accessory Bag (B9108XA)
  • 1 - Hard Case (93015)
  • 1 - User's Manual
Optional Accessories
B9108XA Yokogawa B9108XA Accessory Carrying Case Buy Now Sale $10.45
(Reg. $11.00)
93013 Yokogawa 93013 My-Protection Cover Buy Now $11.00
93015 Yokogawa 93015 MY10 and MY40 Carrying Case Buy Now Sale $35.51
(Reg. $42.00)
98002 Yokogawa 98002 My-Earth Probe Buy Now $21.00
99005 Yokogawa 99005 My-shoulder strap Buy Now $11.00