A system includes a testing device, a current clamp, and circuitry for converting an electrical current. The testing device is configured to measure a characteristic relating to electrical equipment and to transmit data representing the measured characteristic to a remote computing device. The electrical equipment includes an electrical conductor carrying an electric current. The current clamp forms a current transformer. The current clamp is configured to be clamped around the electrical conductor and the current transformer is configured to induce an electric current from the electrical conductor. The circuitry is configured to convert the induced electric current to a direct current that is usable to power the testing device.