By Alma Krause on January 30 2018 03:33:50
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.
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.
Insulated cables are rated by their allowable operating voltage and their maximum operating temperature at the conductor surface. A cable may carry multiple usage ratings for applications, for example, one rating for dry installations and another when exposed to moisture or oil.
A wiring diagram is a simplified conventional pictorial representation of an electrical circuit. It shows the components of the circuit as simplified shapes, and the power and signal connections between the devices. A wiring diagram is often used to troubleshoot problems and to make sure that all the connections have been made and that everything is present.