COMPARISON · MULTIMETERS
Fluke 1587 FC vs Fluke 87V: Which Tester Do You Need?
You need the Fluke 1587 FC if you test insulation: it applies 50 to 1000 V DC to a de-energized motor, cable or transformer winding, reads up to 2 GΩ, and runs PI and DAR ratio tests logged to your phone. You need the Fluke 87V if you want the more precise everyday multimeter: ±(0.05% + 1) DC volts against ±(0.09% + 2), True RMS AC, a 10 A current input, 200 kHz frequency and 250 µs peak capture. The 1587 FC has no 10 A input at all, and the 87V cannot test insulation. Many motor technicians end up carrying both.
By the OhmSavvy Research Team ·
Disclosure: OhmSavvy earns a commission from qualifying Amazon purchases made through these links, at no extra cost to you. How we're funded.
Fluke 1587 FC
4.6★★★★★A True RMS multimeter and 50–1000 V insulation tester in one, with PI/DAR tests and Fluke Connect logging to your phone.
Fluke 87V
4.8★★★★★The step-up pick for anyone who needs CAT IV protection and high-resolution readings daily.
Specs side by side
| Fluke 1587 FC | Fluke 87V | |
|---|---|---|
| Rating | 4.6★★★★★ | 4.8★★★★★ |
| Accuracy | True RMS, ±(0.09% + 2) DC V | True RMS |
| Safety rating | CAT IV 600V / CAT III 1000V | CAT III 1000V / CAT IV 600V |
| Auto-ranging | Yes (manual override) | Yes |
| Best for | Motor, cable and insulation testing | Industrial technicians, daily professional use |
| Insulation test | 50, 100, 250, 500, 1000 V; 0.01 MΩ to 2 GΩ | No |
| PI / DAR | Yes, timed ratio tests | No |
| Live-circuit protection on IR test | Won't start if > 30 V on the terminals | Not applicable |
| Wireless logging | Fluke Connect: app memory, TrendIt graphs | None |
| DC volts accuracy | ±(0.09% + 2), 6 V to 1000 V | ±(0.05% + 1) |
| AC volts accuracy | ±(1% + 3) at 50–60 Hz | ±(0.7% + 2) |
| Current | 60 mA and 400 mA only; no 10 A input | To 10 A (20 A for 30 s); 0.01 µA DC resolution |
| Resistance | To 50 MΩ, ±(0.9% + 2) to 6 MΩ | To 50 MΩ, ±(0.2% + 1) |
| Frequency | To 99.99 kHz | To 200 kHz |
| Temperature | -40 to 537 °C (K-type included) | -200 to 1090 °C, excl. probe (80BK included) |
| Display | 6,000 counts | 6,000 counts; 19,999 hi-res |
| IP rating | IP40 (non-operating) | IP30 |
| Weight | 550 g (Amazon lists 1645 g) | 355 g (624 g with holster) |
| Battery | 4 × AA; at least 1000 insulation tests | 9V, ~400 h |
| Case | Fluke says both soft case and hard case | Holster with tilt-leg |
| Warranty | 3 years | Lifetime |
Specs checked against manufacturer documentation and official Amazon listings. Fluke 87V is hands-on tested by OhmSavvy; the Fluke 1587 FC assessment is desk research. How we research.
Key differences
- →Insulation testing: only the 1587 FC applies a high DC test voltage (50 to 1000 V) and reads leakage resistance up to 2 GΩ. The 87V's ohms function uses a low test voltage and tops out at 50 MΩ, so it can't stress insulation.
- →PI and DAR: the 1587 FC runs timed ratio tests and logs them to the Fluke Connect app with TrendIt graphs. The 87V has no logging.
- →Current: the 1587 FC measures only to 400 mA through a 0.44 A fuse. The 87V reads to 10 A (20 A for 30 seconds) and resolves 0.01 µA DC.
- →Precision: the 87V's DC volts are ±(0.05% + 1) against ±(0.09% + 2), and its AC volts ±(0.7% + 2) against ±(1% + 3) at 50–60 Hz. It also has a 19,999-count hi-res mode and 250 µs peak capture.
- →Shared: CAT IV 600V / CAT III 1000V, a low-pass filter for drives, capacitance to 9,999 µF, resistance to 50 MΩ and a K-type temperature input.
- →Ownership: the 87V carries a lifetime warranty, the 1587 FC three years.
Two different jobs
These two Flukes rarely compete. A multimeter asks "what is the circuit doing right now?" with the power on. An insulation tester asks "will this winding or cable hold up when the power comes back?" with the power off. The 1587 FC answers the second question and keeps a capable meter on board; the 87V answers the first question more precisely and doesn't touch the second.
1587 FC: megohms
50 to 1000 V DC test voltage, readings to 2 GΩ.
1587 FC: PI/DAR
Timed ratio tests, trended in the Fluke Connect app.
1587 FC: no 10 A
Current stops at 400 mA.
87V: precision
±(0.05% + 1) DC volts and a 19,999-count mode.
87V: 10 A and µA
10 A input plus 0.01 µA DC resolution.
Same CAT rating
CAT IV 600V / CAT III 1000V on both.
The 87V is a meter we bought and tested, rated 4.8. The 1587 FC is rated 4.6 from Fluke's specs and its Amazon listing; we haven't tested it. For the 87V in depth, see our Fluke 87V review.
Fluke 1587 FC vs 87V spec by spec
| Spec | Fluke 1587 FC | Fluke 87V | Edge |
|---|---|---|---|
| Insulation test voltages | 50 / 100 / 250 / 500 / 1000 V | None | 1587 FC |
| Insulation range | 0.01 MΩ to 2.0 GΩ | None | 1587 FC |
| IR accuracy, 250–1000 V | ±(1.5% + 5) to 600 MΩ | None | 1587 FC |
| Auto discharge | < 0.5 s for 1 µF or less | None | 1587 FC |
| DC volts | ±(0.09% + 2), 6 V to 1000 V | ±(0.05% + 1), to 1000 V | 87V |
| AC volts, 50–60 Hz | ±(1% + 3) | ±(0.7% + 2) | 87V |
| Low-pass filter | Yes | Yes, 3 dB at 1 kHz | Same |
| Current | 60 mA / 400 mA, AC and DC | To 10 A; 0.01 µA DC resolution | 87V |
| Resistance | ±(0.9% + 2) to 6 MΩ; 50 MΩ | ±(0.2% + 1), to 50 MΩ | 87V |
| Capacitance | To 9,999 µF, ±(1.2% + 2) | To 9,999 µF | Same |
| Frequency | To 99.99 kHz, ±(0.1% + 1) | To 200 kHz, ±(0.005% + 1) | 87V |
| Temperature | -40 to 537 °C | -200 to 1090 °C (excl. probe) | 87V |
| Peak capture | Not listed | 250 µs | 87V |
| Wireless / logging | Fluke Connect, TrendIt | None | 1587 FC |
| Operating temperature | -20 to 55 °C | -20 to 55 °C | Same |
| Warranty | 3 years | Lifetime | 87V |
Bars use a logarithmic scale: each step is ten times the last.
Bars use a logarithmic scale: each step is ten times the last.
Source conflicts we couldn't resolve
How an insulation test works
Good winding insulation still leaks a tiny current. Apply a known DC voltage between the copper and the frame, measure that leakage, and Ohm's law gives the insulation resistance. The 1587 FC sources 1 mA when the load is at the bottom of each range (for example 1 mA into 1 MΩ at 1000 V), and far less through healthy insulation. Moisture, carbon dust, oil and cracked varnish all give the current an easier path, so the megohm reading falls.
Why can't the 87V do this? Its ohms function drives a small test current at a low voltage, chosen so it won't damage components. Insulation that reads "OL" at a few volts can still break down at the 480 V a motor sees in service, plus the spikes riding on it. Only a test at or above working voltage reveals that weakness, which is why the 1587 FC offers 500 V and 1000 V test levels.
PI and DAR: why the trend matters more than one number
A single megohm reading moves with temperature and humidity, so it's hard to judge on its own. Ratio tests fix that. Clean, dry insulation keeps absorbing charge for minutes, so its resistance climbs over the test; wet or contaminated insulation leaks steadily, so the reading stays flat. Two common ratios capture the climb:
01
De-energize and isolate
Lock out, lift the feeder, prove dead
02
Apply test voltage
e.g. 500 V for a 480 V motor (common practice)
03
DAR
60-second reading ÷ 30-second reading
04
PI
10-minute reading ÷ 1-minute reading
05
Discharge and log
Auto discharge; save to Fluke Connect
| Illustrative example | 1 min | 10 min | PI | Reading |
|---|---|---|---|---|
| Dry, clean winding | 400 MΩ | 1,000 MΩ | 2.5 | Healthy by common guidance |
| Damp or dirty winding | 40 MΩ | 48 MΩ | 1.2 | Investigate: dry and clean, retest |
These figures are worked examples, not measurements. A PI of 2.0 or more is the guideline commonly cited from IEEE 43 for most modern motor insulation classes; follow the motor maker's or your plant's acceptance criteria where they exist. The 1587 FC times the test and computes the ratio for you, and Fluke Connect stores each result so the next test can be compared against it. Fluke also lists temperature compensation in the app, which helps when last year's test was taken on a hotter day. For lower-voltage winding checks with an ordinary meter, see our guide on checking a motor winding for a short.
Fluke 1587 FC vs 87V: which tester do you need?
| Your work | Tool | Why |
|---|---|---|
| Motor rewind or repair shop | Fluke 1587 FC | Insulation, PI and DAR before and after every job |
| Plant PM on motors and feeders | Fluke 1587 FC | Trend insulation over years in the app |
| Troubleshooting drives and controls | Fluke 87V | Low-pass filter, peak capture, tighter accuracy |
| Running-current checks up to 10 A | Fluke 87V | The 1587 FC stops at 400 mA |
| Flame sensors and µA signals | Fluke 87V | 0.01 µA DC resolution |
| Commissioning new cable runs | Fluke 1587 FC | Insulation test before first energization |
| Do both in one van | Both | Megohms from the 1587 FC, precision and amps from the 87V |
The missing 10 A input is less painful than it sounds, because motor currents are usually read with a clamp anyway. Fluke sells the 1587 FC in kits with a clamp accessory (sold as separate listings). Our clamp meter buying guide covers the options. If you only need a precise meter, compare the 87V with its siblings in Fluke 87V vs Fluke 179 and Fluke 87V vs Fluke 289.
Safety: insulation testing puts high voltage on purpose
Choose the Fluke 1587 FC if…
- ✓You check motor windings, feeders or transformers for insulation breakdown before re-energizing
- ✓You want polarization index (PI) and dielectric absorption ratio (DAR) tests with trend graphs in an app
- ✓You want one tool for megohm testing plus everyday volts, ohms, capacitance and temperature
Choose the Fluke 87V if…
- ✓You measure load current in series up to 10 A, or microamps down to 0.01 µA DC resolution
- ✓You want tighter DC accuracy, a 19,999-count hi-res mode and peak capture for intermittent faults
- ✓Insulation testing is done by someone else, or you already own a dedicated megohmmeter
The bottom line
Buy the Fluke 1587 FC if you maintain motors, cables or transformers: its 50–1000 V insulation test, PI/DAR ratios and Fluke Connect trending answer questions no multimeter can, and it still covers everyday volts, ohms, capacitance and temperature. Buy the Fluke 87V, our hands-on tested pick, if you need a precision meter: tighter DC and AC accuracy, a 10 A input, microamp resolution, 200 kHz and peak capture. For motor work, the two complement each other well.
Frequently asked questions
Can the Fluke 87V test insulation resistance?+
No. The 87V's resistance function tops out at 50 MΩ and uses a low test voltage, so it can't stress insulation the way a megohmmeter does. Weak insulation can read open at a few volts and still fail at 480 V. For winding and cable insulation tests you need a tester like the 1587 FC, which applies 50 to 1000 V DC.
Can the Fluke 1587 FC measure amps?+
Only small currents. Fluke lists 60 mA and 400 mA ranges, AC and DC, protected by a 0.44 A fuse, with a 600 mA overload allowed for two minutes. There is no 10 A input, so it can't read a motor's running current in series. Use a clamp meter for that, or carry an 87V, which reads to 10 A.
What test voltage should I use on a 480 V motor?+
Common practice, based on IEEE 43 guidance, is a 500 V DC test for motors rated up to about 1000 V, with 1000 V DC used for some higher-rated equipment. The 1587 FC offers 50, 100, 250, 500 and 1000 V. Always check the motor maker's instructions first, and never test with drives or electronics still connected.
What is a good PI reading?+
A polarization index of 2.0 or higher is the guideline commonly cited from IEEE 43 for most modern motor insulation, while readings near 1.0 suggest moisture or contamination. PI is the 10-minute reading divided by the 1-minute reading. Trends matter more than one result, which is why the 1587 FC's Fluke Connect logging is useful.
Is the Fluke 1587 FC accurate enough as an everyday multimeter?+
For most field work, yes. Fluke lists ±(0.09% + 2) on DC volts, ±(1% + 3) on AC volts at 50–60 Hz, a low-pass filter, capacitance to 9,999 µF and temperature to 537 °C. The 87V is tighter, at ±(0.05% + 1) DC and ±(0.7% + 2) AC, and adds a hi-res mode and 10 A input.
Does the Fluke 1587 FC need Fluke Connect to work?+
No. Insulation tests and meter functions run on the instrument itself. Fluke Connect adds phone features: saving readings in the app, TrendIt graphs of PI and DAR tests, temperature compensation and sharing results. Fluke lists asset history and trending as Fluke Connect Assets, sold separately, so check what your plan needs before relying on it.
Related
