By Ashley Rojas on February 02 2018 02:33:37
The environment of the installed wires determine how much current a cable is permitted to carry. Because multiple conductors bundled in a cable cannot dissipate heat as easily as single insulated conductors, those circuits are always rated at a lower "ampacity". Tables in electrical safety codes give the maximum allowable current based on size of conductor, voltage potential, insulation type and thickness, and the temperature rating of the cable itself. The allowable current will also be different for wet or dry locations, for hot (attic) or cool (underground) locations. In a run of cable through several areas, the part with the lowest rating becomes the rating of the overall run.
In North American practice, an overhead cable from a transformer on a power pole to a residential electrical service usually consists of three twisted (triplexed) conductors, with one being a bare neutral conductor, with the other two being the insulated conductors for both of the two 180 degree out of phase 120 V line voltages normally supplied. The neutral conductor is often a supporting "messenger" steel wire, which is used to support the insulated Line conductors.
The wiring diagram lets you define the different installation components and locations (cabinets, control panels, consoles, connection boxes, etc.) and gives you a synoptic, functional view of the installation. The terminal strips and cabling connections between locations can be defined at the beginning, during or at the end of the project design. The length of the pathways can also be defined by the user and thus serve as a default value, for all cables within the given pathway.
Use wiring diagrams to assist in building or manufacturing the circuit or electronic device. They are also useful for making repairs. DIY enthusiasts use wiring diagrams but they are also common in home building and auto repair.