This article describes the development and implementation of a modified ammeter to facilitate fraud detection in low-voltage consumer units. The device has three modules: the first is a meter affixed to the top of a stick, which is the local unit and it measures the consumer current; the second is another instrument that transmits the measured current after the customer’s meter via radio frequency, and it is the remote unit; and the third is a receiver unit that displays the measurements made by the local and remote units. On the receiver unit display, the operator can check and compare the two (local and remote) measures detecting fraud by determining if there is a difference between the measures. The paper illustrates field measurements performed in a test for a Brazilian electric utility