Fluke 1587 FC vs Fluke 289: Insulation Testing or Data Logging?

Specs side by side

Specs checked against manufacturer documentation and official Amazon listings. Desk research, not bench testing. How we research.

Key differences

• →Insulation testing is the 1587 FC's alone: five test voltages from 50 to 1000 V, readings to 2 GΩ and timed PI/DAR ratios. The 289 has no insulation function.
• →Unattended recording is the 289's strength: it stores up to 10,000 intervals plus events with a real-time clock on the meter. The 1587 FC saves and graphs through the Fluke Connect phone app instead.
• →Current range: the 289 runs from a 0.01 µA step on its 500 µA range up to 10 A. The 1587 FC has 60 mA and 400 mA ranges only.
• →Low resistance: the 289's 50 Ω range resolves 0.001 Ω at up to 10 mA; the 1587 FC's meter side starts at 0.1 Ω.
• →Resolution and accuracy: 50,000 counts and ±(0.025% + 2) DC volts on the 289, against 6,000 counts and ±(0.09% + 2) on the 1587 FC.
• →Identical: True RMS AC, CAT IV 600V / CAT III 1000V, a low-pass filter for drive outputs and a thermocouple temperature input.

Power off, power on: two halves of a motor job

Think about how a motor problem usually unfolds. A drive trips at odd hours, or a pump motor runs hot. The first question is what the supply and load are doing while it runs, and that's a recording job: leave a meter on the circuit through a shift and come back to a timeline. The second question, once the machine is locked out, is whether the windings and the feeder cable are still sound, and that's an insulation job. The 289 is built for the first question and the 1587 FC for the second.

Two resistance tests that share only the ohm symbol

Both meters measure resistance at the extremes, but from opposite ends. The 289's low-ohm range drives up to 10 mA through a connection and resolves a thousandth of an ohm, using no more than about 20 V of open-circuit voltage. The 1587 FC's insulation test drives about 1 mA into a short and holds the test voltage you choose, up to 1000 V, to find leakage paths in the gigaohm region.

Why can't the 289's 500 MΩ range stand in for an insulation tester? Because a weakened insulation path often looks fine at a few volts and only starts conducting when it is stressed near the voltage the equipment sees in service. That's a widely accepted engineering principle, not a figure from Fluke, but it's the reason insulation testers exist. Going the other way, the 1587 FC's meter side starts at 0.1 Ω, too coarse to compare three winding phases that may differ by a few milliohms, which is where the 289's 50 Ω range and its relative mode for zeroing the leads come in. Fluke describes that range as two-terminal, not four-wire Kelvin. Our motor winding short test guide walks through the meter side of that check.

Before you press the insulation test button

The 289 doesn't raise this question, since its highest test source is the roughly 20 V of its low-ohm range. That doesn't make it harmless: logging sessions are usually set up on energized circuits, so the same CAT IV 600V / CAT III 1000V rules for leads, PPE and arc-flash boundaries apply when you clip it on.

Where each meter keeps its records

Both meters can build a history, but they put it in different places. The 289 holds the record itself: up to 10,000 sample intervals plus events, each with a real-time-clock stamp, graphed on its own screen with TrendCapture and downloadable over an IR link to FlukeView Forms. You can walk away with no phone in range. The 1587 FC sends readings over Fluke Connect, where the app stores them, draws TrendIt graphs and applies temperature compensation to insulation results. Our sources don't list an on-meter memory for it.

PI is the 10-minute reading divided by the 1-minute reading, and DAR divides the 60-second reading by the 30-second one. Rising values usually mean clean, dry insulation; flat values point to moisture or contamination. We go deeper on the ratios on Fluke 1587 FC vs 87V. For other approaches to remote readings, see Fluke 3000 FC vs 289.

As an everyday meter, the 289 reaches further

Set aside the specialist functions and the 289 is the broader meter on nearly every line. Its 50,000-count display shows 4.9999 V where a 6,000-count meter shows 4.999 V, and its DC accuracy line is close to four times tighter. The bigger practical gap is current: the 1587 FC tops out at 400 mA, so motor and heater currents need a clamp, while the 289 takes up to 10 A directly and also reads microamps.

The 289 also lists LoZ for ghost voltages and 250 µs peak capture; our 1587 FC sources state neither. Both carry a low-pass filter for drive outputs, so motor-lead voltage on a VFD is readable on either. The 1587 FC has one edge on the meter side: its K-type thermocouple comes in the box, while the 289's box contents aren't stated in our data.

Weight, batteries and warranty

The 289's large display and recorder are thirsty: six AA cells for a 100-hour minimum, or 200 hours in logging mode. The 1587 FC gets about 1000 hours of meter use from four AA cells and Fluke quotes at least 1000 insulation tests per set. Warranties differ too. The 289 carries a lifetime limited warranty; the 1587 FC has three years, which Fluke says registration can extend to five, though that offer may end without notice. The 1587 FC's case is IP40 when not operating; our 289 sources give no IP rating. Fluke's own pages also disagree on whether the 1587 FC ships with a soft or a hard case.

Which should you buy?

If you only need insulation at 500 V and 1000 V, the simpler meter in Fluke 1577 vs 1587 FC may be enough. If you want the 289's recorder without the low-ohm range and LoZ, read Fluke 289 vs 287. Sealed-site buyers should also see Fluke 1587 FC vs 87V MAX.

Who should skip each

Skip the 1587 FC if you never test insulation. Without that function you're paying for a 6,000-count meter with no 10 A jack and no microamp range, and a general-purpose Fluke covers more ground. Skip it too if you need records without a phone nearby.

Skip the 289 if your job is deciding whether equipment is safe to energize: no amount of logging or resolution replaces a high-voltage insulation test. Skip it as well if weight and battery changes bother you, or if a 6,000-count meter already covers your readings. Neither meter is owner-tested by OhmSavvy; both verdicts are desk research against Fluke's published specifications.

Frequently asked questions