Table 220.55 of the National Electrical Code (NEC) provides a standardized method for calculating the demand load for electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances. In this lesson, we will discuss how to use Table 220.55 to determine the demand load for cooking appliances.

Determine the Rating of the Cooking Appliance The first step in using Table 220.55 is to determine the rating of the cooking appliance. This can be found on the nameplate of the appliance or in the manufacturer’s specifications. The rating is typically given in kilowatts or amperes.

Determine the Type of Cooking Appliance Once the rating has been determined, the next step is to determine the type of cooking appliance. Table 220.55 is divided into three sections based on the type of appliance: electric ranges, wall-mounted ovens and counter-mounted cooking units, and other household cooking appliances.

Locate the Appropriate Column and Row Using the rating and type of appliance, locate the appropriate column and row in Table 220.55. The columns correspond to the rating of the appliance, while the rows correspond to the number of appliances.

Determine the Demand Load Once the appropriate column and row have been located, the demand load for the cooking appliance can be determined. This information is listed in the table and corresponds to the rating and number of appliances.

It is important to note that Table 220.55 provides the maximum demand load for the cooking appliances and that the actual load may be less. For example, if two cooking appliances are used at the same time, the actual load may be less than the maximum demand load listed in the table.

In addition, Table 220.55 is only one method for calculating the demand load for cooking appliances and may not be appropriate for all types of installations or situations. It is important to consult the specific requirements of Article 220 of the NEC and to use professional judgment when calculating the demand load.

Overall, Table 220.55 provides a standardized method for calculating the demand load for electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances. By following the steps outlined above, it is possible to use Table 220.55 to determine the demand load for a given cooking appliance or set of appliances.

It is important to note that Table 220.55 is updated every three years with each new edition of the NEC. Therefore, it is important to use the most current version of the table to ensure accurate calculations.

In summary, using Table 220.55 of the NEC involves determining the rating of the cooking appliance, determining the type of appliance, locating the appropriate column and row in the table, and determining the demand load. It is important to use professional judgment and consult the specific requirements of Article 220 of the NEC when calculating the demand load.