Shelly 120A Current Transformer Clamp for Energy Monitoring
The Shelly 120A Current Transformer Clamp is a precision split-core current transformer designed to work with compatible Shelly energy monitoring devices such as the Shelly EM. This clamp delivers 1% accuracy and allows you to measure electrical currents up to 120 amps from a live cable without the need to disconnect or cut wires. Perfect for monitoring whole-home electrical loads, high-capacity circuits, and large appliances in residential, commercial, or industrial environments.
Why Choose the Shelly 120A CT Clamp?
This current transformer clamp offers contactless, non-invasive current measurement for seamless integration with your Shelly smart home energy monitoring ecosystem. The clamp is designed to accurately measure high-current loads by converting them into lower, standardised values for energy monitoring, ensuring reliable current sensing without interfering with the primary circuit.
Key Features
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High Current Capacity: Measures alternating current (AC) up to 120 amperes for heavy-duty applications
- 1% Accuracy: Precision measurement for reliable energy monitoring
- 16mm Internal Diameter: Clamps around standard residential and commercial cables
- 60 cm Cable Length: Provides flexible installation options
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Split-Core Design: Easy installation without disconnecting wires
- Ferrite Core Construction: Durable and reliable performance
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Compatible with Shelly EM: Seamlessly integrates with Shelly energy meters for real-time monitoring via the Shelly app
How It Works
Current transformers scale the large values of current to small, standardised values for measuring purposes, providing a secondary current that is accurately proportional to the current flowing in its primary circuit. The clamp fits around the live cable without the need to cut or disconnect the wire, unlike a traditional inline ammeter. The 60 cm cable connects directly to your Shelly EM or compatible energy monitoring device, allowing you to track energy consumption, monitor circuit performance, and optimise electrical usage from anywhere using the Shelly Cloud app.
Perfect For
- Whole-home energy monitoring
- Solar panel system monitoring
- Commercial and industrial electrical installations
- High-capacity appliance monitoring (air conditioners, heat pumps, electric vehicle chargers)
- Electrical circuit analysis and load balancing
- Prepaid energy management and consumption tracking
Compatibility
Compatible with: Shelly EM, Shelly Pro 3EM-120A, Shelly EM Gen4
NOT compatible with: Shelly Pro EM-50, Shelly Pro 3EM, Shelly EM Gen3, Shelly EM Gen4, Shelly Pro 3EM-3CT63
Installation Made Easy
The split-core design allows the clamp to open and close around existing cables, making installation quick and straightforward. The 60 cm cable provides flexibility for mounting in electrical panels, meter boxes, and distribution boards. For optimal accuracy and performance, it's best to keep the cables at their original length without extension.
What's in the Box
- 1 × Shelly 120A Current Transformer Clamp (with 60 cm cable)
- User manual
Full Specifications
| Rated Primary Current |
120A |
| Rated Secondary Current |
40mA |
| Accuracy |
1% |
| Saturation Current |
≥ 120A |
| Core Type |
Ferrite core |
| Internal Diameter (Aperture) |
16mm |
| Cable Length |
60 cm |
| Load Resistance |
20Ω |
| Electrical Strength |
3000 VAC at 1 mA 60s |
| Clamp Type |
Split-core current transformer |
| Compatibility |
Shelly EM, Shelly Pro 3EM-120A, Shelly EM Gen4 |
Specifications are sourced from the manufacturer product page and may be updated.
Important: All electrical installation work must be performed by a qualified and licensed electrician to ensure safety and compliance with local electrical codes.
