Meters and troubleshootingQuestion 1123 of 1506

A 200:5 CT feeds an ammeter that reads 3.5 A. What is the current in the primary conductor?

140 A
3.5 A
17.5 A
87.5 A

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Correct answer: 140 A

The ratio is 200:5, or 40:1. The line current is 3.5 A x 40 = 140 A.

Source: Lessons in Electric Circuits II: AC (Kuphaldt), 10.7: Special Transformers and Applications

Questions last reviewed: 18 October 2026

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