The Fluke 1587 FC and 1577 Insulation Multimeters combine a digital insulation tester with a full-featured, true-RMS digital multimeter in a single compact, handheld unit. Both models share the same physical platform and CAT III 1000 V / CAT IV 600 V safety rating, but differ in measurement breadth and connectivity: the 1587 FC adds Fluke Connect wireless capability, a wider insulation test voltage range (50 V, 100 V, 250 V, 500 V, 1000 V), a VFD low-pass filter, frequency, capacitance, diode test, temperature, and Min/Max functions, while the 1577 covers the core insulation testing application at 500 V and 1000 V with the standard DMM functions.

An insulation multimeter combines two separate instruments that electricians, motor maintenance technicians, and industrial maintenance teams have historically had to carry separately: a megohmmeter for testing the insulation integrity of motor windings, cables, and electrical distribution components, and a digital multimeter for routine voltage, current, and resistance troubleshooting. Combining them into one handheld unit reduces the number of tools required for motor and drive maintenance, electrical commissioning, and preventative maintenance routes — particularly valuable when working at heights, in confined spaces, or on service calls where carrying multiple instruments is impractical.

Brand Heritage

Fluke Corporation was founded in 1948 in Seattle, Washington by John Fluke Sr. The company has been part of the Danaher Corporation industrial conglomerate since 1998, and since 2016 has operated under Danaher's spin-off Fortive Corporation. The Fluke brand has been maintained consistently across these ownership transitions — instruments sold under the Fluke name today share the same brand lineage as instruments manufactured decades earlier under the original John Fluke Manufacturing Company.

Compare Other Models in This Series

The Fluke 1587 FC and 1577 share a common platform — same physical form factor, same safety ratings, same core DMM measurement functions, and the same three-year warranty extendable to five years through Fluke registration. Both combine an insulation tester with a true-RMS DMM in a single handheld unit rated for CAT III 1000 V / CAT IV 600 V environments, and both include the same hard case, remote probe, test leads, and alligator clips.

The two models differ along two axes: insulation testing breadth and feature set. The 1587 FC offers five insulation test voltages (50, 100, 250, 500, 1000 V) across a 0.01 MΩ to 2 GΩ range and adds frequency, capacitance, diode test, temperature, Min/Max, VFD low-pass filter, and Fluke Connect wireless capability. The 1577 offers two insulation test voltages (500, 1000 V) across a 0.1 MΩ to 600 MΩ range with the core DMM functions only — a streamlined choice when the application centers on routine insulation checks at standard voltages without the broader DMM and connectivity feature set.

Each new model below is its own dedicated product page with condition-matched pricing and the appropriate documentation. Select the model that matches your application requirement — insulation test voltage range, DMM feature breadth, and connectivity needs — and the product page will reflect the corresponding specifications and accessory list.

The 1587 FC is the broader-capability model: five insulation test voltages spanning from 50 V (suitable for low-voltage electronic and telecom work) to 1000 V (motor and distribution work), insulation measurement to 2 GΩ, and a full feature set including capacitance, frequency, temperature with K-type thermocouple, diode test, Min/Max, and the VFD low-pass filter for variable frequency drive measurements. Fluke Connect support adds wireless PI/DAR testing with TrendIt graphs, memory storage, and temperature compensation through the smartphone app.

The 1577 is the focused-application model: two standard insulation test voltages (500 V and 1000 V) covering the most common motor and electrical maintenance test routines, insulation measurement to 600 MΩ, and the core true-RMS DMM functions (AC/DC voltage, DC millivolts, AC/DC milliamps, resistance, continuity). The 1577 does not include capacitance, frequency, diode test, temperature, Min/Max, VFD filter, or Fluke Connect. The comparison table below summarizes the specification differences between the two models.

Additional differences in specifications beyond the few shown above are not listed here — see each model's full specifications below.

Accessories Supplied

• Remote probe
• Test leads and probes
• Alligator clips
• K-type thermocouple
• Hard case
• User documentation

Product Core & Specifications

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.