Understanding CT Coils: Current Transformers for Safe Current Measurement

Current Transformers - CT COIL

A CT coil, or Current Transformer coil, is a crucial component in modern power systems. It is widely used in electrical panels, metering, and protection systems to safely measure high alternating current (AC), especially in industrial and commercial installations.

What Does a CT Coil Do?

A CT coil reduces high current levels to a safer, measurable value for electrical instruments like:

• Ammeters
• Energy meters
• Protective relays
• Monitoring devices

Instead of exposing these instruments to dangerous high-voltage lines, a current transformer steps down the current to ensure safe and accurate readings.

How Does a CT Coil Work?

• The primary winding carries the high current—typically a single turn or conductor passed through the CT.
• The secondary winding has multiple turns and outputs a proportional, reduced current (commonly 5A or 1A).
• This reduced current is safely fed into measurement and protection devices.

Example of CT Coil Ratio:

If a CT coil has a 1000:5 ratio, it means 1000 amps flowing through the primary will produce 5 amps on the secondary—safe for monitoring equipment.

⚠️ Safety Note:

Never leave the secondary side of a CT coil open while current flows in the primary. This can result in high-voltage buildup, potentially damaging equipment and posing a serious electrical hazard.

Why Use CT Coils?

CT coils are essential for:

• Safe current measurement
• Accurate energy monitoring
• Reliable electrical protection

Whether for industrial automation, commercial buildings, or substation maintenance, CT coils are vital tools in your electrical safety arsenal.

✅ Need a CT Coil?

We stock approved CT coils up to 2500A. Contact us today to learn more or place your order!