Fluke 368 FC vs Hioki CM4001

For small AC residual-current work, our first pick is the Fluke 368 FC: its 3 mA range and 0.001 mA resolution give it the stronger low-end specification here. Choose Hioki CM4001 when access between crowded wires matters more, its 0.60 mA accuracy floor covers your work, and you also want AC load measurement up to 600.0 A. Both measure AC current; readers investigating vehicle battery drain should use our DC clamp-meter guide.

Quick picks

• Smaller AC leakage or a larger bundle: Fluke 368 FC, with a 40 mm jaw and built-in memory.
• Narrow gaps and leakage-to-load work: Hioki CM4001, with slim jaws, a comparator and a 24 mm opening.
• Hioki wireless recording: choose the documented CM4001-90 adapter bundle, or add Z3210 to the bare meter; use GENNECT Cross on a compatible mobile device.

Fluke 368 FC vs Hioki CM4001 at a glance

These are manufacturer specifications. The minimum-current entries describe different limits; neither should be substituted for display resolution.

Compare specifications and all conditions

Current measurement

Fluke 368 FC

True RMS AC; up to 60 A

Hioki CM4001

True RMS AC; up to 600.0 A

Lowest range / display step

Fluke 368 FC

3 mA / 0.001 mA

Hioki CM4001

60.00 mA / 0.01 mA

Documented low end

Fluke 368 FC

Minimum value: 10 μA rms

Hioki CM4001

Accuracy guaranteed from 0.60 mA

Low-range basic accuracy

Fluke 368 FC

±(1% of reading + 5 digits), through 30 A

Hioki CM4001

±(1.5% of reading + 5 digits), through 6.000 A at 45–66 Hz

Jaw opening

Fluke 368 FC

40 mm

Hioki CM4001

24 mm

Filter specification

Fluke 368 FC

Accuracy band: 40–70 Hz on; 40 Hz–1 kHz off

Hioki CM4001

Low-pass cutoff: 180 Hz ±30 Hz at −3 dB

Category / voltage

Fluke 368 FC

CAT III 600 V / CAT IV 300 V

Hioki CM4001

CAT III 300 V

Recording purchase

Fluke 368 FC

Internal memory: up to 65,000 measurement points; Fluke Connect for graphs

Hioki CM4001

Z3210 plus GENNECT Cross for app-configured events; adapter included with CM4001-90

Full comparison table ↔

Swipe to compare. Row labels stay visible.

Buying detail	Fluke 368 FC	Hioki CM4001
Current measurement	True RMS AC; up to 60 A	True RMS AC; up to 600.0 A
Lowest range / display step	3 mA / 0.001 mA	60.00 mA / 0.01 mA
Documented low end	Minimum value: 10 μA rms	Accuracy guaranteed from 0.60 mA
Low-range basic accuracy	±(1% of reading + 5 digits), through 30 A	±(1.5% of reading + 5 digits), through 6.000 A at 45–66 Hz
Jaw opening	40 mm	24 mm
Filter specification	Accuracy band: 40–70 Hz on; 40 Hz–1 kHz off	Low-pass cutoff: 180 Hz ±30 Hz at −3 dB
Category / voltage	CAT III 600 V / CAT IV 300 V	CAT III 300 V
Recording purchase	Internal memory: up to 65,000 measurement points; Fluke Connect for graphs	Z3210 plus GENNECT Cross for app-configured events; adapter included with CM4001-90

Buying detail	Fluke 368 FC	Hioki CM4001
Current measurement	True RMS AC; up to 60 A	True RMS AC; up to 600.0 A
Lowest range / display step	3 mA / 0.001 mA	60.00 mA / 0.01 mA
Documented low end	Minimum value: 10 μA rms	Accuracy guaranteed from 0.60 mA
Low-range basic accuracy	±(1% of reading + 5 digits), through 30 A	±(1.5% of reading + 5 digits), through 6.000 A at 45–66 Hz
Jaw opening	40 mm	24 mm
Filter specification	Accuracy band: 40–70 Hz on; 40 Hz–1 kHz off	Low-pass cutoff: 180 Hz ±30 Hz at −3 dB
Category / voltage	CAT III 600 V / CAT IV 300 V	CAT III 300 V
Recording purchase	Internal memory: up to 65,000 measurement points; Fluke Connect for graphs	Z3210 plus GENNECT Cross for app-configured events; adapter included with CM4001-90

Sources: Fluke US specifications, Fluke family datasheet, Hioki US specifications, CM4001 basic manual and Hioki recording instructions.

• Yes: AC residual-current investigation: both meters belong on the shortlist
• No: DC battery-drain measurement: neither has a DC-current specification
• Partly: Hioki wireless event records: add the adapter and mobile app

Best for smaller AC leakage: Fluke 368 FC

The reason to buy the 368 FC is its low-current range, rather than its maximum amperage. Fluke's range table specifies 3 mA, 30 mA and 300 mA, followed by the amp ranges. The finest display step is 1 μA, but the footnote gives a 10 μA rms minimum. Do not interpret the finest step as a promise of accurate measurement at that step.

The 40 mm jaw is useful when the required conductor bundle would exceed Hioki's opening. Fluke also specifies a shielded jaw, a forward-facing worklight, hold and Max/Min/Average readings. At 500 g, it is a different carry proposition from Hioki's 115 g instrument; choose access and measurement requirements before pocketability.

For recording, Fluke lists internal memory for up to 65,000 measurement points. Its FC quick reference illustrates the meter's LOG control and direct connection to the Fluke Connect app; the datasheet documents app graphs for trending. A memory-point count alone does not establish recording duration or transient-capture speed. Before a long unattended job, verify the intended capture and retrieval workflow against the linked documentation and current app.

Buy it for: smaller AC leakage, the larger jaw, or the Fluke Connect workflow. Choose Hioki instead when the slim jaw solves an access problem and its low-end specification is sufficient.

See the exact Fluke 368 FC package.

Best for crowded wiring: Hioki CM4001

Hioki's CM4001 page emphasizes narrow jaws for crowded cables. The 24 mm opening accommodates a smaller bundle than Fluke's; slim jaw shape and maximum opening answer different access questions. Check both the gap available to insert the jaw and the bundle that must fit inside it.

Its 60.00 mA range resolves 0.01 mA, while the accuracy guarantee begins at 0.60 mA. Above that floor, the combination of leakage measurement and 600.0 A AC load capacity makes it our mixed-work choice when the installation rating also fits. It includes a comparator that gives audio alerts and a red backlight against a selected threshold.

The bare meter also has a simple event logging function: it displays the maximum since recording began and flashes red when the threshold is exceeded. That is useful local monitoring. For event times and retrievable app records, buy the wireless setup described below.

Buy it for: access, local threshold alerts and leakage-to-load coverage. Choose Fluke instead if you need the finer bottom range, larger opening or its higher category/voltage specification.

See CM4001 and the CM4001-90 bundle.

How we choose

We compared official US product pages, range tables, the maker-linked manuals, filter guidance and documented package contents. These recommendations are based on manufacturer specifications and compatibility documentation; thisMETER has no physical test results for these meters. We prioritize the useful low-current range, installation rating, jaw access and complete recording purchase over the largest amperage number. Read our selection method for the site's approach.

Buying guide: accuracy, filters and installation fit

Read the digits term and the accuracy floor

On the bottom range, Fluke's basic specification adds 5 digits to 1% of the reading, with each digit representing 0.001 mA. Hioki adds 5 digits to 1.5%, with 0.01 mA steps. Thus, comparing only the percentage hides an important difference in small-current uncertainty. Changing range also changes the display step: Fluke's 30 mA range uses 0.01 mA steps.

Apply the conditions, too. Fluke states reference conditions of 23 ±5°C, maximum 80% relative humidity, and accuracy valid for one year after calibration. Hioki's basic manual specifies 23 ±5°C, 80% RH or less, a one-year accuracy guarantee and sine-wave input. Neither headline True RMS claim removes the waveform, frequency or environmental limits in its accuracy table.

Filter settings change what you are comparing

Fluke specifies its filtered accuracy over 40–70 Hz, and unfiltered accuracy over 40 Hz–1 kHz. Hioki specifies a low-pass cutoff of 180 Hz ±30 Hz at −3 dB. A frequency band for an accuracy specification and a filter cutoff are different specifications; do not treat those numbers as interchangeable filter settings.

Hioki explains that switching supplies and inverters can superimpose high-frequency components on leakage current. Decide whether the job calls for suppressing those components, then record the filter state with the result. Comparing a filtered reading with an unfiltered one can change the question being answered.

There is also a specific CM4001 trap. Hioki's filter instructions warn that the enabled filter can produce a value lower than the actual current. If readings differ greatly between ranges, Hioki says to trust the upper range; its support FAQ explains the harmonic-overrange interaction and recommends manual ranging upward. Treat this as a buying consideration for distorted installations, rather than assuming every stable low reading is trustworthy.

Match the jaw to the measurement arrangement

Hioki's manual distinguishes residual measurement around the relevant supply-wire bundle from measurement on a ground wire; its load-current instructions specify a single conductor. Those arrangements require different physical access. Assess the complete bundle you need to accommodate, rather than the diameter of one conductor alone, and follow the maker's diagrams for the actual circuit.

Hioki also warns that nearby high currents, special inverter-output waveforms and incompletely closed jaws can compromise accuracy. A jaw that nominally fits but cannot close completely is a reason to choose another setup. For ordinary load-current choices, use our general clamp-meter guide.

Recording: buy the workflow, not just the radio

For Hioki's app-configured events, the documented chain is CM4001 + Z3210 + GENNECT Cross on a compatible phone or tablet. The manual describes recording event occurrence time, stop time and maximum value. The wireless instructions limit storage to 99 events and warn that events shorter than 200 ms may be missed or measured inaccurately. Recording stops at the event limit; starting another session deletes previous event data.

That function is distinct from the bare meter's simple maximum-value display. It is also distinct from Excel Direct Input: Hioki's complete manual says GENNECT Cross and the HID function cannot run concurrently. Choose the mode for the result you need, and check the current app's compatibility on your intended mobile device before ordering.

For monitoring duration, Hioki specifies approximately 32 hours without Z3210, or 16 hours with it and wireless communication; its basic manual conditions include backlight off and no input. Fluke specifies more than 150 hours without backlight or spotlight, but does not identify that figure as a guaranteed wireless-logging runtime. Plan power and data retrieval for the actual session rather than treating these battery figures as equivalent recording guarantees.

Packages and variants: what to order

Fluke's family datasheet distinguishes 368 from 368 FC: wireless compatibility is specified for the FC models. It also lists 369 FC with a 61 mm jaw and a different low-range accuracy specification. Do not silently substitute it for the 368 FC reviewed here. Hioki's US adapter page names CM4001 as compatible with Z3210.

Neither a radio nor an accessory cable supplies an absent measurement function. In particular, Hioki lists the CM4001's voltage range and output function as N/A. If an external recorder output is essential, reconsider the instrument before ordering accessories.

1. 1

   Match the measurement

   Select the useful AC range, accuracy conditions, jaw fit and installation rating.

2. 2

   Match the recording

   Choose local display, internal logging or app-configured event records for the job.

3. 3

   Match the package

   Confirm the exact model suffix, adapter contents and compatible mobile device before buying.

Verdict

Choose Fluke 368 FC first for smaller AC leakage and its larger jaw. Choose Hioki CM4001 for slim-jaw access, threshold alerts and broader AC load coverage when its accuracy floor and installation rating fit. For Hioki app event records, order CM4001-90, or CM4001 plus Z3210, and include the compatible mobile device and GENNECT Cross in the plan.