Testo 750-3 Voltage Tester – 690 V AC/DC, LC Display, Rotary Field, Single-Pole Phase and RCD Test, with Flashlight (0590 7503)

Testo 750-3 (product code 0590 7503) is the most comprehensive model in the Testo 750 voltage tester family. It performs voltage tests in the range 10 … 690 V AC/DC; in addition to the all-round LED display readable from any angle using fiber-optic technology, it has an LC display that shows the measured value numerically. It is used in electrical panels and systems for determining the absence of voltage and power, continuity testing, rotary field checks, single-pole phase testing and residual current device (RCD) tripping tests. It complies with DIN EN 61243-3.

LED Display Readable from Any Angle and LC Display Showing the Value

The patented all-round LED display ensures that the voltage indication can be read clearly no matter how the instrument is held; the second LC display shows the measured value. The integrated flashlight illuminates dark measuring points. The non-slip ring and ergonomic handle provide comfortable working, and the robust housing withstands field conditions.

Residual current circuit breakers are tested with the RC tripping function; the vibrating load buttons prevent accidental tripping. It is a practical tester for checking the voltage supply on live cables and determining the rotary field direction on three-phase systems.

Technical Specifications (Official Testo Data)

• Brand / Model: Testo 750-3 voltage tester · product code 0590 7503
• Voltage: 10 … 690 V AC/DC · resolution 1 V · accuracy ±(3% + 5 digits)
• Continuity Test: < 500 kΩ
• Rotary Field Test: 170 … 690 V phase-to-phase, 50/60 Hz
• Single-Pole Phase Test: 100 … 690 V AC, 50/60 Hz
• Other Functions: RCD/RC tripping · vibrating load buttons · measuring point illumination (flashlight)
• Display: fiber-optic all-round LED display + single-line LCD
• Measurement Category: CAT IV 600 V · CAT III 690 V
• Protection Class: IP64
• Power Supply: 2 × AAA batteries
• Operating / Storage Temperature: −10 … +50 °C / −15 … +60 °C · operating humidity 0–95% RH
• Dimensions / Weight: 270 × 72 × 35 mm · 295 g
• Approval / Standard: TÜV, CSA, CE · EN 61243-3 · EN 61326-1 · EN 61010-1

Scope of Delivery

• Testo 750-3 voltage tester
• Test probe protector and test probe caps
• Batteries
• Test protocol and instruction manual

Technician Tips

• Test on a known source before use: before verifying the absence of voltage, test the instrument on a socket known to be live, and test it again after measuring.
• Check the phase sequence on compressors and fans: verify the phase sequence with the rotary field test before connecting a three-phase motor; a reversed phase causes reverse rotation.
• A single-pole test is a preliminary check: a single-probe phase test gives a quick indication; confirm the absence of voltage with a two-pole voltage test.
• Inform users before an RCD test: RC tripping trips the residual current device; take into account that the appliances on the line will lose power before testing.
• Fit the probe caps: work with the test probe caps in a CAT IV environment; do not use an instrument with damaged probes.

Technical document: Testo 750 voltage tester datasheet (PDF, English)