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Klein CL110 Clamp Meter: Specs, How to Use It, and Why It Was Discontinued

The Klein CL110 is a 400 A AC clamp meter that also reads AC and DC voltage, resistance and continuity through its test leads. It has a 1.12 inch jaw, a 2,000-count backlit display and a CAT III 600 V safety rating. Klein has since stopped making it, and the company points buyers to the CL120 as its updated model. This guide explains what the CL110 measures, how to take a reading step by step, where its limits are, and what to check before you buy a used unit.

Quick answer

Use the clamp only for AC current, use the leads for voltage and resistance, and check the meter on a known source before each use. Klein no longer makes the CL110 and names the CL120 as its updated model.

What the CL110 is built to measure

A clamp meter reads current without breaking the circuit. You open the jaw, close it around one insulated conductor, and the meter reads the magnetic field that the current creates. On the CL110, that clamp function covers AC current only, up to 400 A. Klein’s product page states this directly: the clamp measures AC current, while voltage, resistance and continuity are read through the test leads.

The listed voltage range is 600 V AC and 600 V DC. The meter is rated CAT III 600 V, Class 2 and double insulated. That rating tells you the highest transient overvoltage the meter can handle in a distribution or branch circuit environment. It does not mean the meter is safe on every high energy source, so you should always check the category rating against the work you plan to do.

Specifications from the manufacturer and the manual

Klein’s product page and the instruction manual listing on ManualsLib agree on the core facts. The CL110 runs on three AAA batteries and has a jaw opening of about 1.12 inches, or 2.8 cm. The display is a 2,000-count LCD with a backlight, which helps when you are working under a sink or inside a panel. The meter is listed with a drop rating of 3.3 feet, or 1 meter. The operating temperature range is 0 to 50 degrees C (32 to 122 degrees F) at altitudes up to 2,000 meters.

The Klein page also lists a 20 MΩ resistance range. The same page shows the value as “20MO” in its spec table, so the figure is consistent with the manufacturer’s own listing but was not cross-checked against a second manufacturer document. The page includes the meter’s included items: a carrying case, test leads of about 41 inches, and batteries. The meter powers itself off after 15 minutes without use, which saves the batteries if you forget to switch it off.

How to take a reading with the CL110

The manufacturer’s summary gives a short sequence of warnings. The steps below combine those warnings with standard clamp meter practice. They are not a substitute for the full manual, which you should read before first use.

Step 1: Check the meter before you rely on it

Klein says to verify meter operation by measuring a known voltage or current before each use. In practice, that means testing a live outlet or a known source and confirming that the meter responds. If the display does not change, or the reading is clearly wrong, do not use the meter for that job.

Step 2: Set the function and the range

Turn the dial to AC current for clamp readings. For voltage, switch to AC or DC volts and move the red lead to the voltage jack. Start on the highest range if you do not know the expected value, then step down. The CL110 has a 400 A current position, so a conductor carrying a small load will read low on that range, and a more sensitive setting may be needed for light loads.

Step 3: Clamp around one conductor only

Place the jaw around a single insulated wire. If you clamp both the supply and return conductors of a two wire cable, the fields cancel and the reading will show close to zero. Close the jaw fully so the sensor sits flat, and keep your fingers behind the finger guard.

Step 4: Use the leads for voltage and resistance

Voltage and resistance readings come from the test leads, not from the clamp. Touch the probes to the points you want to measure, and keep your hands behind the probe guards. Klein’s notes say not to measure resistance or continuity on live circuits. Power the circuit off, confirm it is dead, and then test resistance or continuity.

Step 5: Read the display and log the result

Wait for the number to settle before you record it. On an AC current reading, check that the value makes sense for the load. For a motor, a steady reading that rises sharply on startup and then falls is normal. A reading that stays at zero when you know current is flowing usually means the jaw is not fully closed or the clamp is around both conductors.

Where the CL110 falls short

The CL110 is an AC clamp with lead based voltage and resistance functions. The sources we opened do not state whether its current reading is true RMS, so do not assume it is. If you work with variable speed drives, LED lighting or other non sinusoidal loads, check the waveform handling in the current Klein documentation or pick a meter whose spec sheet names true RMS.

The meter is also no longer in production. That matters for warranty and replacement parts. A used unit may come without leads, a case or a working battery door. Check that the jaw closes flat, the display shows every segment, and the function switch clicks through every position. If the seller cannot confirm the test lead condition, budget for a new set of leads.

Buying a CL110 today or choosing a successor

Klein’s site describes the CL120 as the updated model in the same family. For most readers who want the same 400 A AC range and the same CAT III 600 V rating, the CL120 is the simpler choice because it is still sold new. If you already own a CL110 and it works, you do not need to replace it for basic AC current checks. Keep the manual with the meter so the warnings stay within reach.

When you compare a used CL110 with a new meter, look at the total cost, not just the sticker price. Add batteries, a replacement set of leads if needed and any case you want. Then compare that total with a new clamp that has a warranty and an updated manual. A cheaper used meter is only a good deal if it reads correctly on a known source.

How we chose these sources

We picked the manufacturer’s own US and UK product pages first, since they carry the official spec table and the discontinuation notice. We added a third readable page, a ManualsLib summary of the general specifications, as an independent copy of the same data. We skipped sites that returned access errors during our checks.

What we could not verify

We were able to open three readable sources: Klein’s US product page, Klein’s UK product page and a manual summary hosted on ManualsLib. We did not open the full English PDF manual, and the product pages link to instruction downloads whose text was not available to us. So the step by step procedure above is built from the warnings and general clamp practice in those pages, not from the full manual’s own sequence. We also did not test a unit, so we cannot confirm the accuracy figures or the auto power off behavior on a physical meter.

We did not find an independent lab test of the CL110. Where the sources disagree or are silent, this guide says so rather than filling the gap. The resistance figure appears only on Klein’s pages. Current availability of new stock varies by retailer, and we did not check prices.

FAQ

Is the Klein CL110 still made?

No. Klein’s product page says the CL110 is no longer in production and names the CL120 as its updated model.

Can the CL110 measure DC current?

The manufacturer lists the clamp for AC current. DC voltage is measured through the test leads, so do not expect a DC clamp reading from this meter.

Does the CL110 measure continuity?

Yes, according to Klein’s product page, continuity and resistance are read through the test leads. Do not use these functions on a live circuit.

How do I know the meter is working before a job?

Measure a known live voltage or a known current source before each use, as Klein recommends. If the reading does not respond, stop and check the leads, the batteries and the function setting.

What should I look for on a used CL110?

Check that the jaw closes flat, the display shows all segments, every function position responds, and the leads are intact. Ask whether the case and batteries are included.

Sources

• Klein Tools, CL110 product page (US): https://www.kleintools.com/product/CL110 (opened 2026-10-29)
• Klein Tools, CL110 product page (UK): https://kleintools.co.uk/product/CL110 (opened 2026-10-29)
• ManualsLib, Klein Tools CL110 general specifications: https://manualslib.mx/manual/327364/Klein-Tools-Cl110.html?page=2 (opened 2026-10-29)

For more on how voltage testers differ from meters, read How Do Voltage Testers Work? Plain Explanation. If you are comparing clamp styles before you buy, see True RMS Digital Clamp Meter: Buying Guide.