# GW Instek GCM-403 Digital Clamp Meter # GW Instek GCM-403 Digital Clamp Meter ## Key Features At A Glance - Maximum input rating of AC/DC 600A current and 600V voltage for general electrical work - Measures AC/DC voltage, AC/DC current, resistance, diode, continuity, capacitance, frequency, and temperature - Auto range function (except current measurement) with auto power off - Tapered jaws with 28mm maximum clamp opening diameter - 4000-count LCD display with data hold and REL (relative) function - Temperature measurement from -40°C to 1000°C with included probe - Capacitance measurement up to 100μF and frequency measurement up to 10MHz - Powered by single 9V battery (16F22) for portable field use The Instek GCM-403 is a digital clamp meter designed to measure AC/DC voltage, AC/DC current, resistance, diodes, continuity, capacitance, frequency, and temperature in a single handheld instrument. With its tapered jaws, auto range function, data hold, REL function, and auto power off, the GCM-403 is positioned as a versatile tool for electricians performing a broad range of electrical measurements without the need to carry multiple separate instruments. A clamp meter measures current non-invasively by clamping its jaws around a single conductor — without breaking the circuit or making physical contact with the current-carrying wire. The GCM-403 supports this fundamental clamp meter workflow while combining it with the functions of a digital multimeter, making it suitable for electrical maintenance, troubleshooting, and general field service applications where both current measurement and standard DMM functions are needed. Operating from a 20,000 square foot secure warehouse at 1675 Cambridge Drive in Elgin, Illinois, our in-house technical team inspects, tests, and verifies the instruments we sell — so you receive a clamp meter that has been confirmed to perform as described, not simply forwarded from an unverified source. This combination of authorized distribution, in-house verification, and direct technical support is what distinguishes ValueTronics from pass-through brokers and online marketplaces. ## Brand Heritage GW Instek (Good Will Instrument Co., Ltd.) is a Taiwanese test and measurement manufacturer that has operated under the Instek brand for decades, producing a broad catalog of digital multimeters, clamp meters, oscilloscopes, power supplies, and function generators. The company has remained independent and has not undergone significant corporate name changes, with the Instek brand serving consistently as the product identifier across its global distribution channels. ## Accessories Supplied - User manual x 1 - Test leads - Temperature probe - Carrying case ## Product Core & Specifications Specifications ACV Range 4V, 40V, 400V, 600V Resolution 0.001V, 0.01V, 0.1V, 1V Accuracy ±(1.0 + 5) ~ ±(1.2 + 5) Input Impedance ≥10MΩ // 100pF at least Frequency Response 40–400Hz ACA Range 40A, 600A Resolution 0.01A, 1A Accuracy ±(2.5 + 5) ~ ±(2.5 + 8) Frequency Response 50–60Hz DCV Range 400mV, 4V, 40V, 400V, 600V Resolution 0.1mV, 0.001V, 0.01V, 0.1V, 1V Accuracy ±(0.8 + 1) ~ ±(1.0 + 3) Input Impedance ≥10MΩ DCA Range 40A, 600A Resolution 0.01A, 1A Accuracy ±(2.0 + 5) OHM Range 400Ω, 4kΩ, 40kΩ, 400kΩ, 4MΩ, 40MΩ Resolution 0.1Ω, 0.001kΩ, 0.01kΩ, 0.1kΩ, 0.001MΩ, 0.01MΩ Accuracy ±(1.0 + 2) ~ ±(1.5 + 2) Diode Range 4V Resolution 0.001V Open-circuit Voltage Approx. 1.48V Continuity Range 400Ω Resolution 0.1Ω Accuracy The buzzer turns on for resistance lower than 10Ω Open-circuit Voltage Approx. 0.45V Capacitance Range 40nF, 400nF, 4µF, 40µF, 100µF Resolution 0.01nF, 0.1nF, 0.001µF, 0.01µF, 0.1µF Accuracy ±(4.0 + 3) ~ ±(5.0 + 10) Frequency Range 10Hz, 100Hz, 1kHz, 10kHz, 100kHz, 1MHz, 10MHz Resolution 0.001Hz, 0.01Hz, 0.1Hz, 1Hz, 10Hz, 100Hz, 1kHz Accuracy ±(4.0 + 3) ~ ±(5.0 + 10) Temperature (°C only) Range \-40°C ~ 1000°C Accuracy ±(2.5 + 3) ~ ±(8.0 + 5) Other Function Functions Data Hold, REL LCD Display Display Liquid crystal display; Displays 4000 counts maximum. Clamp Opening Diameter Diameter 28mm Maximum Power Source Battery 9V battery (16F22) Dimensions & Weight Dimensions 210 (L) x 76 (W) x 30 (H) mm Weight Approx. 260g **Important:** Maximum input rating: AC/DC 600A current, AC/DC 600V voltage. Maximum clamp opening diameter: 28mm. **Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.** ## Details - **Price:** 60.0 USD - **Vendor:** GW Instek - **Type:** Dig Clamp Meter - **Tags:** Clamp, Instek, Manufacturers, Meters & DAQ, product_manual_group_3, Product_new ## Variants | Variant | Price | Available | |---------|-------|-----------| | Default Title | 60.00 USD | In stock | ## Images - GW Instek GCM-403 Digital Clamp Meter --- > Source: [ValueTronics](https://valuetronics.com/products/gcm-403-instek-clamp-meter-new) > Updated: 2026-05-30