Electrical code Electrical code An electrical code is a set of regulations for the design and installation of electrical wiring in a building. The intention of a code is to provide standards to ensure electrical wiring systems that are safe for people and property. Such wiring is subject to rigorous safety standards for design and installation. Wires and electrical cables are specified according to the circuit operating voltage and electric current capability, with further restrictions on the environmental conditions, such as ambient temperature range, moisture levels, and exposure to sunlight and chemicals. Associated circuit protection, control and distribution devices within a building's
Electrical telegraph Electrical telegraph An electrical telegraph is a telegraph that uses electrical signals, usually conveyed via dedicated telecommunication circuit or radio. The electrical telegraph, or more commonly just telegraph, superseded optical semaphore telegraph systems, thus becoming the first form of electrical telecommunications. In a matter of decades after their creation in the 1830s, electrical telegraph networks permitted people and commerce to transmit messages across both continents and oceans almost instantly, with widespread social and economic impacts. From early studies of electricity, electrical phenomena were known to travel with great speed, and many experimenters worked on the application of electricity to communications