What the Hioki CM4375 Clamp Meter Does and Its Wireless Successor

ByKen

What the Hioki CM4375 Clamp Meter Does and Its Wireless Successor

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The Hioki CM4375 is a 1000 A AC/DC true RMS clamp meter with a slim jaw. Hioki designed the jaw to fit between cables in crowded electrical distribution boxes, and it lists a -25°C to 65°C operating range and an IP54 enclosure. Hioki’s US page marks the CM4375 as discontinued and shows the CM4375-90 wireless-adapter version in its place. This guide explains what the CM4375 does according to Hioki and a distributor, how its ratings are listed, and where the sources differ.

Quick answer

  • The CM4375 is an automatic AC/DC true RMS clamp meter rated to 1000 A, with a thin sensor for tight cable runs.
  • Hioki’s US page marks the CM4375 as discontinued and shows the CM4375-90 wireless-adapter model as its replacement.
  • Hioki says the meter measures DC voltage up to 1000 V by itself and up to 2000 V with the optional P2000 probe. Hioki also gives a 1700 V figure in its overview, so check the manual for the rating that applies to your setup.

How we chose

We chose two sources that we opened and read. The first is Hioki’s US product page for the CM4375, because it is the manufacturer’s statement of the model’s status, features and ratings. The second is an ITM product page for the CM4375-91 bundle, which includes a full specification block. We did not use search snippets, prices, stock levels, or customer reviews. We did not use other Hioki clamp pages as a source for the CM4375.

What Hioki says about the CM4375

Hioki describes the CM4375 as “a 1000A AC/DC True RMS clamp meter that features a uniquely designed slim jaw that lets you easily get into the narrow gaps between cables in crowded electrical distribution boxes.” The page lists these features:

  • An automatic AC/DC function that Hioki says boosts work efficiency, with measurement up to 1000 A.
  • A thin sensor structure for tight spaces between cables.
  • Simultaneous measurement of inrush current in RMS and crest values.
  • An operating temperature range of -25°C to 65°C.
  • An IP54 dustproof and waterproof enclosure.
  • Data transfer to a smartphone, tablet or Excel file through the free GENNECT Cross app, with the Wireless Adapter Z3210 required for that function.
  • Harmonic analysis from the 1st to the 30th order through GENNECT Cross, with the Z3210 adapter.

The page states that the CM4375 is “Discontinued.” It lists the AC/DC CLAMP METER (1000A) WITH WIRELESS ADAPTER CM4375-90 as the model shown in its place.

Safety ratings as Hioki lists them

Hioki lists “CAT IV 600 V, CAT III 1000 V” as the base rating. With the optional P2000 DC High Voltage Probe, the page lists “CAT III 2000 V, CAT IV 1000 V.” These ratings tell you the category and voltage that the meter, or the meter with the probe, is designed to withstand. Use the rating on the label of your unit and in the manual, and do not connect the meter to a circuit above the rating that applies to your setup.

A slim jaw does not change the category. Clamping in a tight panel still carries the same risk as clamping in an open area, so use insulated gloves and the protective equipment the job requires.

The DC voltage figures

Hioki’s US page makes two DC voltage statements. The overview says the high-voltage DC capability reaches “up to 1700 V.” The key features list says the meter measures “DC voltages of up to 2000 V” when used with the P2000 probe, and the footnote says “The clamp meter itself is capable of measuring up to 1000 V DC.” The ITM bundle page lists a DC voltage range of “600 ｍV to 1000 V (when using P2000: 600 to 2000 V).” The Hioki page and the ITM page agree on 1000 V for the meter alone and 2000 V with the probe. The 1700 V figure appears only in the overview and does not match the feature list, so we do not treat it as the rating.

What the distributor page lists

The ITM page describes the CM4375-91 bundle, which includes the high-voltage probe. It gives these details in the text we read:

  • An AC current range of “1000 A (maximum display 999.9 A, 10 Hz to 1 kHz, true RMS).”
  • A DC current range of “1000 A (maximum display 999.9 A).”
  • A core jaw diameter of “1.34” (Φ34 mm).”
  • The safety rating “CAT IV 600 V, CAT III 1000 V,” with “CAT III 2000 V, CAT IV 1000 V” when using the P2000 probe.

The ITM page does not give an IP rating for the CM4375-91. The IP54 statement we report comes from Hioki’s page, and that page’s description of the enclosure is the reference for it. The ITM page does not mention that the model is discontinued, and it lists availability as “3 to 4 Weeks.”

Choosing between the base model and the bundle

The base CM4375 measures up to 1000 V DC on its own. The bundle with the P2000 probe extends the DC range to 2000 V, according to both sources. If your work is on solar arrays or other high-voltage DC systems, the probe is the part to confirm. If your work stays at mains voltage and below, the base meter may cover your needs, but confirm the rating against the circuit you will measure.

Because Hioki lists the CM4375 as discontinued, check whether the wireless adapter and probe are available in the same form you need. The page names the CM4375-90 as the wireless-adapter version, and the ITM page shows the CM4375-91 bundle.

Frequently asked questions

Is the CM4375 still sold by Hioki?

Hioki’s US page marks the CM4375 as discontinued and names the CM4375-90 as the replacement. The page does not list current stock, so check Hioki for the current listing.

Does the CM4375 measure DC current?

Yes. Hioki says the automatic AC/DC function measures both, and the ITM page lists a DC current range of 1000 A.

What is the difference between the CM4375 and the CM4375-90?

Hioki’s US page says the CM4375-90 is the wireless-adapter version. The page does not list the full difference, so compare the order codes in the manual before you choose.

Why does the DC voltage rating look different on each page?

The overview on Hioki’s page gives 1700 V, while the feature list gives 2000 V with the probe. The ITM page gives 1000 V alone and 2000 V with the probe. We use the feature list and the footnote as the reference.

Can I send readings to a computer?

Hioki says data transfers to an Excel file through GENNECT Cross, and the Wireless Adapter Z3210 is required for that function.

Related reading

For background on the clamp principle, see our guide on how a current clamp works. For a separate first check on live conductors, see our guide on Klein non-contact voltage detectors.

What we could not verify

  • The Hioki overview’s 1700 V figure does not match the feature list or the footnote, and we could not confirm which figure applies to the base meter.
  • The ITM bundle page does not give an IP rating for the CM4375-91, so the IP54 statement comes only from Hioki’s page.
  • The two sources do not describe the wireless adapter’s range, battery life or compatibility with every phone, so we do not state those figures.
  • The sources do not give a full AC or DC current accuracy table, so we do not give one.

Bottom line

The Hioki CM4375 is a discontinued 1000 A AC/DC clamp meter with a slim jaw for crowded panels. Confirm the DC voltage rating for your setup, and use the probe and the isolation guidance in the manual for any high-voltage DC work.

Sources

  • Hioki, AC/DC CLAMP METER CM4375 product page (US): https://www.hioki.com/us-en/products/clamp-meters/ac-dc-clamp/id_6707 (opened 2026-10-30)
  • ITM, Hioki CM4375 AC/DC Clamp Meter with High Voltage Probe, 1000 A: https://www.itm.com/product/hioki-cm4375-ac-dc-clamp-meter-and-high-voltage-probe-bundle (opened 2026-10-30)

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