Non-Invasive SCT-013 30A AC Sensor Split Core Current Transformer

📌 What It Is
A non‑invasive current sensor that measures AC current up to ±30 A without cutting or interrupting the conductor.
Uses a split‑core current transformer (CT) — you just clip it around a single live (or neutral) conductor.
It outputs a small AC voltage or current proportional to the sensed AC current.
Ideal for energy monitoring, power measurement, load tracking, and safety systems.
🧠 How It Works
The SCT‑013 is a current transformer:
• The primary winding is simply the conductor passing through the sensor’s core.
• The secondary winding is the internal coil around the magnetic core.
When AC flows through the primary conductor, an equivalent current is induced in the secondary winding proportional to the primary current.
This induced current is converted to a voltage across a burden resistor for measurement.
Because it’s non‑invasive, you never connect directly to mains — the sensor magnetically senses the current.
🔍 Key Features
✔ Split‑Core Design: Clip‑on installation — no need to disconnect wires.
✔ Rated Current: Up to 30 A AC RMS.
✔ Output Type: AC signal proportional to current.
✔ Burden Resistor: Many versions include a built‑in resistor so the sensor outputs voltage (e.g., 1 V or 0–1 V RMS).
✔ Frequency: Designed for 50 Hz/60 Hz mains.
✔ Isolation: Galvanic isolation — the sensor doesn’t electrically connect to the mains line.
✔ Compact & Lightweight: Easy to mount in enclosures, panels, or behind DIN rails.
📋 Typical Electrical Specifications
Specification
Typical Value
Primary Current Range
0–30 A AC RMS
Output
AC voltage (via internal/external burden resistor)
Burden Resistor (Typical)
~33 Ω – 100 Ω (depending on model; defines output voltage)
Core Type
Ferrite or similar magnetic core
Accuracy
~±1–3 % (varies by manufacturer, load, and current range)
Operating Frequency
~45–65 Hz (standard mains)
Insulation
Galvanic isolation between sensor and mains
Output Range (Example)
0–1 V RMS (with internal burden)
📌 Output & Signal Conditioning
The CT itself produces an AC signal proportional to the sensed current.
If the module has a built‑in burden resistor, the output is a voltage that microcontroller ADCs can read (after offset).
Without a burden resistor, you’ll need to add one externally and then measure the resulting voltage.
Because the output crosses zero and is AC, you need to bias the signal to mid‑supply (e.g., VCC/2) before feeding to an ADC.
🧠 Typical Connections
Clip Sensor Around Live or Neutral Wire – do not include both conductors (that cancels the measurement).
Burden Resistor – if external, connect across the sensor leads.
Signal Conditioning – bias the AC waveform (e.g., using a voltage divider and capacitor) so it’s centered at mid‑ADC voltage.
Microcontroller ADC – read the biased waveform and use code to calculate RMS.
📐 Practical Use & Measurements
RMS Current Calculation: Sample the AC waveform at high speed (e.g., 1–4 kHz sample rate), remove bias, and compute RMS value.
Power Measurement: Combine current measurement with synchronized voltage measurement to compute real power.
Energy Monitoring: Integrate real power over time to get energy (e.g., kWh).
Load Profiling: Detect on/off cycling and load variations.
⚠️ Important Safety Notes
⚠ Do Not Open Mains Wiring:
– Although non‑invasive, the sensor clips around a live conductor. Make sure insulation is intact and avoid contact with bare wires.
⚠ Grounding & Isolation:
– The sensor output is isolated; keep signal conditioning and microcontroller circuits properly referenced.
⚠ Signal Biasing:
– Because it’s AC, you must bias the sensor signal for microcontroller ADC reading.
⚠ Avoid Clipping Both Wires:
– Only clip around one conductor (live or neutral). Clipping both cancels the measurement.
📌 Typical Applications
Household Energy Monitoring (DIY smart meters).
Solar Inverter Current Sensing.
Industrial Load Monitoring & Control.
Overload & Fault Detection Systems.
Embedded Microcontroller Projects with Power Tracking.
🛠 Summary
Type: Split‑core AC current transformer (non‑invasive).
Range: 0–30 A AC RMS.
Output: AC waveform proportional to current (often with built‑in voltage output via burden resistor).
Interface: Requires biasing and ADC sampling to extract RMS current.
Use Case: Energy monitoring and current measurement without breaking mains circuit.