170 Modern Commercial Wiring Copyright Goodheart-Willcox Co., Inc. 12.2.5 Conductor Color Code Grounded conductors of branch circuits are identifi by color. If the grounded conductor fied is 6 AWG or smaller, it is white, gray, white with a color stripe, or has three continuous white stripes on any color other than green insulation. If wires from different systems are contained in the same raceway, the neutrals of different sys- tems are distinguished from one another. For example, the neutral of one system would be white, the neutral of another system would be gray, and the neutral of a third system would be white with a colored stripe. The equipment grounding conductor must be green, green with yellow stripes, or bare (without any insulation). Hot conductors can be any color except white, gray, green, and white with a color stripe. Nor- mally, hot conductors are black, blue, and red. In a three-phase, four-wire delta system with a neutral connected at the midpoint of a winding, the “high leg” phase conductor should be iden- tifi with orange markings. fied 12.3 Branch-Circuit Loads The Code places load limitations on branch cir- cuits with continuous loads (loads with a dura- tion longer than three hours, such as lighting). The continuous load must not exceed 80% of the circuit rating allotted for it. If the overcurrent protective device is listed for continuous opera- tion at 100% of its rating, the 80% factor is not used. Branch-circuit loads are classifi into five fied fi fi categories: • Lighting loads • Receptacle loads • Equipment loads • Heating and cooling loads • Motor loads. NOTE Motor loads lo are e discussed e e d in Chap pt er 13, M Mo tors. 12.3.1 Lighting Loads In the broad sense, lighting loads may be cat- egorized as follows: • General lighting • Show-window lighting • Track lighting • Sign and outline lighting • Other lighting. Each lighting load is computed separately and then combined to determine the total light- ing load. General Lighting General lighting is the overhead lighting within a building. Its intensity should be adequate for any type of work performed in the area. The general lighting load is the overhead lighting within a building determined by the load per area method or the actual full-load current of the fi xtures used. Determining the general fi lighting load can be based on either the load per area method or the actual full-load current of the fi xtures used, whichever is greater. Within fi a structure, there are normally several differ- ent types of areas—storage, offi hallways, fice, and cafeterias—and these must be considered separately. Most commercial structures have continuous lighting loads and the branch circuits must be adequate for carrying 125% of the calculated load. Code requirements for general lighting loads are found in several sections: • Section 220.12—Lighting Load for Specifiedfi Occupancies • Section 220.14—Other Loads—All Occupancies • Section 220.16—Loads for Additions to Existing Installations • Section 220.18—Maximum Loads. — Table 220.12 of the Code contains minimum general lighting loads (in VA/ft2) for various types of buildings. A condensed version of this table is shown in Figure 12-3. The general light- ing load is calculated by multiplying the floor fl area (in ft2) by the unit load (in VA/ft2). If the