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Klein Tools CL390 digital clamp meter with reverse-contrast LCD display and clamp jaw

Klein Tools CL390 AC/DC Digital Clamp Meter 400 Amp

SKU CH-8QAS-7Z4G2

Measures AC/DC current up to 400 amps with built-in non-contact voltage testing and TRMS accuracy

  • Team affiliation1 Piece
  • Key featuresAC/DC Digital Clamp Meter, Cat III 600v, Cat IV 600v, Batter
  • Overall height8.45 L x 3.51 W x 1.51 H inches
  • Overall width8.45 L x 3.51 W x 1.51 H inches
  • Overall length8.45 L x 3.51 W x 1.51 H inches
  • Product weight0.52 lb (0.24 kg)
  • Measures AC/DC current up to 400 amps via clamp jaw
  • Integrated non-contact voltage tester built into the clamp for quick checks
  • Reverse-contrast LCD display stays readable in bright or dim light
  • Auto-ranging true RMS technology delivers accurate readings across functions
  • Test-lead holder on the clamp body plus optional magnetic hanger for hands-free use

Professional electrical testing tool

The Klein Tools CL390 is a digital clamp meter designed for electricians and technicians who need to measure AC and DC current up to 400 amps without breaking a circuit. It combines clamp-based current and non-contact voltage detection with test-lead functions for voltage, resistance, continuity, frequency, capacitance, diode test, DC microamps and temperature via thermocouple. Auto-ranging and true RMS measurement simplify daily troubleshooting tasks.

Safety ratings and display clarity

The meter carries CAT III 600 V and CAT IV 600 V safety ratings for industrial and utility environments. A reverse-contrast LCD provides high visibility in both bright and dark conditions, reducing eye strain during extended use. The clamp integrates a non-contact voltage tester for quick presence checks, while a side-mounted test-lead holder and optional magnetic hanger accessories keep the workspace organised.

Sustained measurement reliability

True RMS technology maintains accuracy on non-linear waveforms typical of variable-speed drives and electronic ballasts during long sessions. Battery-powered operation supports continuous field work without mains dependency. The compact 8.45 by 3.51 by 1.51 inch form factor and light weight allow one-handed use in tight panels, and the rugged construction reflects over 160 years of professional tool manufacturing experience.

How it compares

Measured against everything we stock in Multimeters & Electrical Testers, at today’s prices. Recalculated every night.

Price $108.99
Pricier than about 90% of the 971 comparable items (median $30.99).

Specifications

Product
Brand nameaFe Power
Size & build
Overall height8.45 L x 3.51 W x 1.51 H inches
Overall width8.45 L x 3.51 W x 1.51 H inches
Overall length8.45 L x 3.51 W x 1.51 H inches
Product weight0.52 lb (0.24 kg)
More details
Team affiliation1 Piece

Questions about this item

How do I measure AC or DC current with the clamp, and what step do people skip?

Open the jaw, place only one conductor inside, then close it fully; the common mistake is clamping both live and neutral together, which cancels the reading.

What will need replacing over time on the CL390?

The two AAA batteries that power the meter and the supplied thermocouple probe for temperature measurements will need periodic replacement.

What is the first measurement limit reached during sustained high-current work?

The clamp is rated to 400 amps AC or DC; exceeding that value triggers the over-range indication before any thermal limit is reached.

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