A dryer typically has a 4-prong plug for safety reasons and to comply with electrical codes. The 4-prong plug configuration is designed to provide a separate grounding path for the dryer, which helps prevent electrical shocks and protects against potential electrical faults.
In the past, dryers were commonly manufactured with a 3-prong plug, which consisted of two hot wires (one for the heating element and one for the motor), and a neutral wire. The neutral wire also served as the grounding connection. However, it was discovered that in certain situations, such as a loose connection, the neutral wire could carry current and create a potential safety hazard.
To address this concern, the National Electrical Code (NEC) in the United States was updated in the late 1990s to require dryers to have a separate grounding conductor. The updated code mandated the use of a 4-prong plug, which includes two hot wires, a neutral wire, and a dedicated grounding wire.
The grounding wire, typically green or bare copper, provides a direct path for any electrical faults or excess current to safely flow into the ground, reducing the risk of electrical shock. By separating the grounding function from the neutral wire, the 4-prong plug configuration enhances the safety of the dryer's electrical system.
If your home has an older 3-prong outlet, it is generally recommended to upgrade the outlet to a 4-prong one and use a matching cord for your dryer to comply with current electrical codes and ensure optimal safety.