What device is used to detect the electrical current to the electric heater coil?

The ammeter is the correct device for detecting the electrical current flowing through the electric heater coil. An ammeter measures the current in amperes, allowing inspectors and electricians to understand how much current is passing through the circuit connected to the heater coil. This measurement is crucial for assessing whether the electric heater operates within its designed electrical specifications and for identifying potential electrical issues, such as overload conditions that could lead to failure or fire hazards.

In contrast, the voltmeter measures the voltage across electrical components and does not provide information about the current flowing within the circuit. The ohmmeter is used to measure resistance and is not suitable for measuring current in a live circuit. While a meter relay is a device used for control purposes or to monitor electrical parameters, it does not specifically measure current like an ammeter does. Hence, the ammeter's ability to directly measure current makes it the appropriate choice for this application.