Fluke 189: What Fluke's Documents State

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The Fluke 189 is a handheld true-RMS digital multimeter. It is the higher model in Fluke’s 187 and 189 pair, and the documents mark its logging and memory functions as model-189 features.

Quick answer

Display: the calibration manual states a primary display of 50,000 counts and a secondary display of 5,000 counts.
Voltage: DC voltage 0 to 1000 V. AC true-RMS voltage from 2.5 mV to 1000 V with a 100 kHz bandwidth.
Current: DC and AC true-RMS current up to 10 A, with 20 A allowed for 30 seconds.
Safety rating: the Spanish user manual states compliance with IEC 61010-1 at 1000 V overvoltage Category III and 600 V overvoltage Category IV, pollution degree 2.
Power: four AA alkaline batteries, per the Spanish user manual.

What the 189 is built to measure

Fluke’s calibration manual lists the basic functions of the 189 as DC voltage, AC voltage, DC current, AC current, resistance, conductance, capacitance and a diode test. Those functions cover most of what a homeowner, car owner or hobbyist needs from a handheld meter: checking whether a socket or battery is live or low, measuring a small load’s current draw, checking a resistor or a fuse for continuity, and testing a diode in an electronics project.

The word “true RMS” matters here. The manual states that AC voltage and current are measured as true RMS, with the AC specifications valid from 5 percent to 100 percent of each range. A true-RMS reading stays closer to the real heating value of a distorted waveform than an average-responding reading does. The calibration manual gives a crest factor limit of up to 3.0 at full scale and 6.0 at half scale for most AC ranges, with 1.5 and 3.0 for the 3000 mV and 1000 V ranges. For a reader, the practical point is simple: the manual specifies accuracy for distorted AC signals within those crest factor limits, and the figures outside them are not covered.

Stated specifications

The table below reproduces the basic specifications in Fluke’s calibration manual for the 187 and 189. Where the basic table gives no accuracy figure for a function, the cell says so rather than filling it from memory.

Function	Stated range	Stated basic accuracy
DC voltage	0 to 1000 V	0.025 %
AC voltage, true RMS	2.5 mV to 1000 V, 100 kHz bandwidth	0.4 %
DC current	0 to 10 A (20 A for 30 seconds)	not given in the basic table
AC current, true RMS	25 uA to 10 A (20 A for 30 seconds)	not given in the basic table
Resistance	0 to 500 megohm	not given in the basic table
Conductance	0 to 500 nS	not given in the basic table
Capacitance	0.001 nF to 50 mF	not given in the basic table
Diode test	3.1 V	not given in the basic table

The calibration manual states that the detailed accuracy tables give the full figures for each function, with the accuracy written as a percentage of reading plus a number of least significant digits. The 5,000-count secondary display is shown with a divide-by-ten note for its least significant digits. A reader who needs the full accuracy for a particular range should open the detailed tables in the calibration manual rather than rely on the basic table above.

Features the documents describe

Several features appear in the feature summary of the calibration manual and apply to the 189 as described:

Dual display and analog bar graph: the bar graph has 51 segments and updates 40 times per second.
Autorange: the manual says the meter selects the best range automatically, with fast autorange.
MIN MAX: records maximum, minimum and average values. FAST MN MX captures peaks to 250 microseconds.
AutoHOLD and duty cycle: holds readings, and measures signal on or off time in percent or milliseconds.
Backlight: two brightness levels.
Serviceability: the battery or fuse can be replaced without voiding calibration, and the manual describes closed-case calibration.

Logging is a model-189 feature. The calibration manual states that readings are recorded to LOGGING memory on the 189 only, and that up to 100 readings can be saved by the user in a memory separate from LOGGING. The Spanish user manual describes the VIEW MEM position as a 189 function. Neither document, as opened for this post, gives a memory depth for automatic logging, so this post does not state one.

Safe use

Mains electricity can kill. Before any work on household wiring, a meter’s rating has to match the circuit. Fluke’s documents state a 1000 V CAT III rating and a 600 V CAT IV rating. Those ratings describe the meter’s protection against transients in a given installation category; they do not make every task on every circuit safe. Panel, service and breaker work belongs to a licensed electrician, not to a reader working alone with a meter.

Current measurement needs more care than voltage measurement. The calibration manual tells the user to check the meter’s fuses before measuring current and to turn power off before connecting the meter for a current reading, and the Spanish user manual gives the same fuse warning. The calibration manual describes a procedure for testing the current fuses F1 and F2, and a separate section on replacing them. A blown fuse gives a misleading reading on current ranges, so the fuse check is the first step on each current measurement.

Voltage checks come first. Before taking a current reading, check voltage on a known source to confirm the meter and leads are working. Keep fingers behind the probe guards and use the holster where the case is damaged or the meter is going into a rough environment. Do not use a meter with a cracked case or damaged leads.

The battery is four AA alkaline cells. The calibration manual states that the batteries should be replaced as soon as the low battery indicator appears, because low batteries can affect readings. Do not rely on a reading taken while the low-battery indicator is showing.

Ratings to check before buying

Model number: confirm you are buying the 189 and not the 187. The logging and VIEW MEM functions are described as 189 features in Fluke’s documents.
CAT rating: the documents state 1000 V CAT III and 600 V CAT IV together. Match the rating to the work and the installation category of the circuit.
Test leads: the meter’s rating does not cover the leads on their own. Check the rating printed on the leads before any mains use, because the documents opened for this post do not describe the leads.
Batteries and fuses: the 189 takes four AA alkaline cells and uses fuses that the user can replace. Keep spare fuses of the rating the manual specifies.
Accessories: the calibration manual mentions a protective holster as a feature. Whether a holster, leads or a case are included with a given purchase is a question for the seller’s listing, not for these documents.

Mistakes to avoid

Measuring current with the leads in the current jacks but the meter set to voltage. Check the function and the jack before every reading.
Exceeding 10 A continuous current. The documents give 20 A for 30 seconds, and anything above that is outside the stated range.
Assuming logging is available on any 187 or 189. The logging functions are marked as 189 functions.
Trusting a reading on a low battery. Replace the cells first.

How we chose

This post covers one model. It does not rank the 189 against other meters. The three documents listed in Sources were opened on 27 October 2026, and each figure is taken from one of them. Where two documents describe the same function differently, this post uses the calibration manual for the specification table and the user manuals for safety and battery text.

What we could not verify

An English user manual for the 187 and 189 was not among the documents opened for this post. The Spanish user and basic manuals were used, and their statements are described in English here.
The documents opened do not give a stated accuracy figure for DC current, AC current, resistance, capacitance or the diode test in the basic table. Read the detailed tables before relying on a figure for those functions.
The documents opened do not state a memory depth for automatic logging on the 189.
The documents opened do not state current availability, price or the contents of any retail package.

Buying checklist

Confirm the model is the 189 and that logging is one of the functions you need.
Check the CAT rating against the most demanding circuit you plan to measure.
Check that the leads you will use carry a rating that matches the meter.
Check the battery and fuse access and confirm you know how to replace the fuses.
If you plan to measure current, confirm the 10 A continuous limit suits the load.

FAQ

What does the Fluke 189 measure?

According to Fluke’s calibration manual, the 189 measures DC and AC voltage, DC and AC current, resistance, conductance, capacitance and it has a diode test. AC measurements are true RMS.

Is the Fluke 189 a true-RMS meter?

Yes. The calibration manual states that AC voltage and current are true RMS, with specifications valid from 5 percent to 100 percent of range.

What voltage is the 189 rated for?

The Spanish user manual states compliance with IEC 61010-1 at 1000 V overvoltage Category III and 600 V overvoltage Category IV, pollution degree 2. Read the rating against the circuit you plan to work on.

Does the 189 log readings?

The calibration manual says logging and VIEW MEM are 189 functions, and that up to 100 readings can be saved by the user in a separate memory.

How many batteries does the 189 use?

Four AA alkaline batteries, according to the Spanish user manual.

Can the 189 measure 10 amps?

The calibration manual states a 10 A continuous range and 20 A for 30 seconds. Above that, the documents give no figure.

Bottom line

If the job is mains voltage, the rule is simple: match the meter’s CAT rating to the circuit, check the fuses before any current reading, and leave panel and service work to a licensed electrician. For a reader who wants logging, confirm the model is the 189, because the documents mark it as a 189 function.

Related reading: for the wider Fluke range, see Fluke Multimeter Lineup: 7 Meters Compared by Stated Function. For leads and their ratings, see Best Fluke 1507 Test Leads: What to Check Before You Buy. For a larger clamp meter, see Best Fluke 1000 Amp Clamp Meter.

Sources

Fluke Corporation, “187/189 True RMS Multimeter Calibration Manual”, PN 1584337, Rev.1 6/02. https://media.fluke.com/8501bf1a-5dda-474b-82f9-b10800be1803_original%20file.pdf (opened 2026-10-27, English)
Fluke Corporation, “Model 187 & 189 True RMS Multimeter Manual de Uso” (Spanish user manual). https://assets.fluke.com/manuals/187_189_umspa0200.pdf (opened 2026-10-27)
Fluke Corporation, “Model 187 & 189 True RMS Multimeter Manual de funcionamiento basico” (Spanish basic operating manual). https://assets.fluke.com/manuals/187_189_gsspa0200.pdf (opened 2026-10-27)

Fluke 189: What Fluke’s Documents State