The following guidelines should be followed when calculating the lighting load:

• Use NEC Table 220.12, shown in this text as Table 3-1, to find the value of volt-amperes per square foot (or per square meter) for general lighting loads, or use the actual volt-amperes if that value is higher.
• For show window lighting, allow 200 voltamperes per linear foot (660 volt-amperes per linear meter), or use the connected load if that value is higher; see NEC 220.14(G).

The NEC defines a show window in Article 100 as: Any window used or designed to be used for the display of goods or advertising material, whether it is fully or partly enclosed or entirely open at the rear and whether or not it has a platform raised higher than the street floor level