NEC Section 422.16 provides rules on flexible cord connected appliances.

Section 422.16(A) provides the general rules and permits flexible cords a follows:

(1) For the connection of appliances to facilitate their frequent interchange or to prevent the transmission of noise or vibration or

(2) To facilitate the removal or disconnection of appliances that are fastened in place, where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance or repair and the appliance is intended or identified for flexible cord connection.

(3) All cord-and-plug-connected electrically heated appliances that produce temperatures in excess of 121°C (250°F) on surfaces with which the cord is likely to be in contact shall be provided with one of the types of heater cords listed in Table 400.4.

Section 422.16(B) provides specific rules for the following cord connected appliances:

• Electrically Operated In-Sink Waste Disposers
• Built-in Dishwashers and Trash Compactors
• Wall-Mounted Ovens and Counter-Mounted Cooking Units
• Range Hoods

In North Dakota, there is an additional allowance for cord connected fuel-fired furnaces in residential dwellings. Refer to the Laws, Rules and Wiring Standards of North Dakota for additional rules pertaining to cord connected fuel-fired furnaces.