66 Modern Commercial Wiring Copyright Goodheart-Willcox Co., Inc. 5.1.4 Temporary Installations The provisions of Article 590 of the Code are spe- cifi cally tailored to apply to temporary electri- cal wiring methods, which may be less exacting than a permanent wiring system. Temporary wiring installations are allowed for the purpose of providing power and lighting to facilities during construction. Temporary wiring can also be used for testing, experimental, and develop- mental purposes. Upon completion of the activ- ity, the temporary lighting must be removed. Bear in mind that Article 590 simply modifi es Code requirements, and that except for those specifi cally modifi ed under that article, all other requirements of the Code apply. Some of the modifi cations and specifi c requirements for temporary wiring are as follows: • All lamps for general lighting will be protected from breakage by a guard over or around the lampholder. • Splices in conductors do not require junction or splice boxes if the conductors are part of a multiconductor cable or open conductors. • Ground-fault circuit-interrupters are required for all 125-volt, single-phase, 15- and 20-amp receptacles that are not fed from permanent wiring circuits. • Regularly scheduled maintenance checks will be performed on equipment grounding conductors. The checks will be performed at not more than three month intervals and will verify continuity, any damaged condition, and proper polarity relative to the grounding electrode conductor. CODE ALERT Temporary Holiday Lights According to Section 590.3(B), temporary electri- cal power and lighting for holiday decoration and similar purposes is allowed for a period not to exceed 90 days. 5.2 Wiring Methods There are three broad classes of wiring meth- ods: cable, raceways, and cable trays. All of the methods are used to connect the power supply, devices, and switches in an electrical circuit. Cable consists of several conductors wrapped by a fl exible outer covering. Raceways are enclo- sures installed between equipment or devices that are to be connected by conductors. The con- ductors or cables are placed inside the raceway, which protects and supports the wiring. Unlike raceways, cable trays are not enclosed they are simply trays on which cables are laid. 5.2.1 Multiconductor Cable Multiconductor cables are fl exible assemblies of conductors having an overall protective cov- ering. There are essentially four major types of multiconductor cable assemblies: • Service-entrance cable • Armored cable • Nonmetallic-sheathed cable • Metal-clad cable. Service-Entrance Cable (SE, USE, and ASE) Service-entrance cable has conductors that can be used not only for service-entrance wiring, but also for indoor applications. Type SE, as shown in Figure 5-6, is unarmored, moisture resistant, and fl ame retardant. It can be composed of two or three insulated conductors and an additional bare conductor. It is readily available in AWG sizes 12 AWG through 4/0 AWG. Type USE is basically the same as type SE except the outer jacketing is better suited for direct burial. It is highly moisture and corro- sion resistant. Type ASE has an armored jacket, which provides additional protection. As already noted, service-entrance cable can be used for interior wiring or for service- entrance cable between the utility supply and