By Jennifer Mireles on January 31 2018 11:52:12
A set of wiring diagrams may be required by the electrical inspection authority to approve connection of the residence to the public electrical supply system. Wiring diagrams will also include panel schedules for circuit breaker panelboards, and riser diagrams for special services such as fire alarm or closed circuit television or other special services.
Some components and symbols of wiring diagram are: Capacitor, used to store electric charge. Toggle Switch, stops the flow of current when open. Push Button Switch, momentarily allows current flow when button is pushed in, breaks current when released. Battery, stores electric charge and generates a constant voltage .Resistor, restricts current flow. Ground wire, used for protection. Circuit breaker, used to protect a circuit from an overload of current. Inductor, a coil that generates a magnetic field. Antenna, transmits and receives radio waves. Surge protector, used to protect a circuit from a spike in voltage. Lamp, generates light when current flows through. Diode, allows current to flow in one direction indicated by an arrowhead or triangle on the wire. Microphone, converts sound into electrical signal. Electrical motor. Transformer, changes AC voltage from high to low or vice versa. Headphone. Thermostat. Electrical outlet. Junction box.
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.
Modern non-metallic sheathed cables, such as (US and Canadian) Types NMB and NMC, consist of two to four wires covered with thermoplastic insulation, plus a bare wire for grounding (bonding), surrounded by a flexible plastic jacket. Some versions wrap the individual conductors in paper before the plastic jacket is applied.