The SCT-013-020 is a precision split-core current transformer (CT) designed for measuring AC currents up to 20A. Unlike the 100A version (SCT-013-000), this model features a built-in sampling (burden) resistor, meaning it provides a direct voltage output (0–1V) proportional to the current. Its clip-on design allows for easy, non-invasive installation on existing wiring without the need for circuit interruption.

Specifications

• Model: SCT-013-020
• Rated Input: 0A – 20A AC
• Max Input: 50A AC
• Rated Output: 0V – 1V AC
• Accuracy: +/- 1%
• Linearity: <= 0.2%
• Frequency Range: 50Hz – 1KHz
• Opening Size: 13mm x 13mm
• Dielectric Strength: 3500V AC / 1 min
• Work Voltage: 720V
• Operating Temperature: -25C to +70C
• Flame Resistance: UL94-V0

Features

• Integrated Burden Resistor: Simplifies your circuit design because the module converts the internal current signal into a 1V AC output signal automatically. You can connect it directly to an ADC (with a bias circuit).
• Split-Core Convenience: The snap-lock mechanism allows the sensor to be clipped around a single wire safely while the power is on.
• High Linearity: With a linearity of <= 0.2%, it provides highly consistent readings across its entire 20A range, making it suitable for precise energy sub-metering.
• Standard Interface: Comes with a 1-meter cable terminated in a 3.5mm audio jack, compatible with many standard energy monitoring shields.
• Industrial Safety: Meets GB1208-2006 standards and features high dielectric strength to ensure isolation between high-voltage mains and your electronics.

Pin & Wiring Configuration

• Output Signal: The 3.5mm jack outputs an AC voltage.
• No External Resistor Needed: Since the sampling resistor is built-in, do not add an external burden resistor, as this will result in incorrect readings.

Common Applications

• Appliance Power Monitoring: Ideal for tracking the consumption of specific household loads like washing machines, dishwashers, or refrigerators.
• HVAC Control: Monitoring current draw for fans and small compressors to detect mechanical wear or filter clogs.
• Smart Home Automation: Providing real-time current data to a central hub for energy-saving automation rules.
• AC Motor Protection: Ensuring small industrial motors are operating within their rated 20A current limit.

Usage Tips

• Single Conductor Only: Ensure the sensor is clipped around only the Live or the Neutral wire. Clipping it around a complete cable containing both wires will result in a 0V reading.
• ADC Biasing: Because the output is an AC sine wave swinging between -1V and +1V, you must use a voltage divider (offset) to lift the signal to a positive range (e.g., cantered at 2.5V) before connecting it to a DC-only ADC like an Arduino.
• Scaling: In your code, an output of 1V AC corresponds to 20A of primary current.