Klein Tools CL380 Digital Electrical Tester, AC/DC Clamp Meter, Auto-Ranging, 400 Amp

The CL380 jaw opens to 1.8 inches (4.6 cm), so a single 1-inch diameter conductor clears it with room to spare. That covers most branch circuits and typical service-entrance conductors up to roughly that size. What it will not do is swallow a whole bundle of conductors or a large feeder over 1.8 inches across, and remember a clamp reading is only meaningful around one conductor at a time anyway.

The CL380 carries a CAT III 600V rating with Class 2 double insulation. CAT III 600V covers distribution panels, feeders and branch circuits at 600V and below, so a 480V three-phase panel is inside the rating. Voltage measurement tops out at 600 V AC and 600 V DC. Do not put it on a 480V service entrance or anything upstream that calls for CAT IV, and never on a circuit above its category rating.

Both. The clamp measures 400 A AC and DC, which is the reason to pick this one over an AC-only clamp. That makes it usable on solar arrays, battery banks, DC motor circuits and automotive work, not just AC branch circuits. There is a DC polarity indicator on the display, so you can see current direction rather than guessing at your clamp orientation. Through the test leads it also reads AC and DC voltage to 600 V.

Yes, and that's a real strength of it. The CL380 reads DC micro-amps to 200 uA through the leads, which is the range a flame sensor signal lives in, so an HVAC tech can verify flame rectification without a second meter. It also measures temperature with a K-type thermocouple probe from -40 F to 1832 F (-40 C to 1000 C) for supply and return air or flue readings, and the probe is in the box. Add resistance to 40 megohm, continuity, frequency, duty cycle and capacitance for checking motor run caps.

Nothing else is needed. The CL380 ships with test leads, a K-type thermocouple probe, a carrying case, the instruction manual and 3 x AAA batteries installed. Between the clamp and the leads that covers current, voltage, resistance, continuity, frequency, duty cycle, capacitance, diode test and temperature out of the box. Klein lists 69142 and 69409 as accessories for it, and 69028 and 69410 as replacement parts if a lead or probe gets damaged later.

A clamp meter earns its place when you need current readings on a live circuit without breaking into it, which is most of what service and troubleshooting work involves. The CL380 does that to 400 A AC and DC, and it also does everything a basic multimeter does through its test leads: AC and DC voltage to 600 V, resistance to 40 megohm, continuity, frequency, duty cycle, capacitance and diode test. So it replaces a multimeter for most field work rather than sitting alongside one. Where a bench multimeter still wins is fine in-line current measurement through the meter itself and tighter resolution on small values.

No. A non-contact voltage tester is built into the clamp jaw of the CL380, so the first check of whether a conductor is hot happens with the same tool already in your hand. For a maintenance tech working off a ladder or in a panel, that's one fewer thing on the belt. Standard practice still applies: before each use, verify the meter by measuring a known voltage or current.

It uses auto-ranging True RMS measurement, which is what you need on the distorted, non-sinusoidal waveforms that VFDs, electronic ballasts and switching supplies produce. An averaging meter reads those low. Frequency measurement runs 10 Hz to 60 kHz for 8 V to 220 V AC RMS, and duty cycle is on board too, so you can characterize a drive output or a PWM signal rather than just confirm voltage.

Yes, capacitance measurement goes to 4000 uF through the test leads, which covers HVAC run and start capacitors. Pair that with the 400 A AC clamp reading on the compressor or blower leg and you can tell a weak cap from a locked rotor on the same call. Discharge the capacitor before you put leads on it.

It meets requirements for use in basic and controlled electromagnetic environments, which Klein defines as residential, office and light-industrial locations. For MRO and facilities work in those settings it's within scope at CAT III 600V. Heavy industrial environments with high electromagnetic interference, or any circuit above 600 V or requiring a CAT IV rating, are outside what this meter is specified for.

It's built to withstand a 6.6 foot (2 m) drop, which covers a fall off a step ladder or out of a bucket onto a slab. Body is plastic and electronics, and it weighs 8.3 oz (236 g), so it's light enough to hold overhead one-handed while you read the display. The included carrying case is what keeps the leads and thermocouple probe from getting chewed up in a truck bin.

The display is a 4000 count reverse contrast LCD, chosen for readability across ambient lighting, from a dim crawlspace to outdoors in the sun. The 4000 count is the practical part for measurement: you get resolution to the tenth on a 400 A reading rather than whole amps. Data hold freezes a value so you can pull the clamp out of a tight panel and then read it, and max/min plus rel/zero let you catch inrush or null out a lead offset.

Auto power off kicks in after five minutes to save the batteries, so a long unattended watch is not what this meter is for. If you need to catch an intermittent, use the max/min function instead of staring at the live reading, then recall it. There's a low battery indicator and the battery compartment opens without tearing the meter down, which matters when the batteries are 3 x AAA and you're swapping them in a panel room.

It measures 8.66 inches overall length, 3.03 inches height and 1.61 inches width, at 8.3 oz (236 g). That's a slim profile that drops into a standard tool pouch or a bag pocket, and the 1.61 inch width is why it works in a crowded panel where a fatter body won't clear the gutter. A carrying case is included if you'd rather keep it with the leads and probe.

Klein Tools CL380 is the full designation, and CL380 is also the manufacturer part number, so there are no suffixes or configuration codes to specify. Klein's own naming for the configuration is AC/DC Current/Temperature, which distinguishes it from CL-series clamps that read AC current only or omit the thermocouple input.