Why does the cord of an electric heater not glow while the heating element does?
Why does the cord of an electric heater not glow while the heating element does?

The heating element of an electric heater is composed of a high-resistance alloy. When the current passes through the heating element, it becomes overheated and glows red. The cord is generally composed of low-resistance copper or aluminium. As a result, the cable does not illuminate.