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A distribution board (also known as panelboard, circuit breaker panel, breaker panel, electric panel, fuse box or DB box) is a component of an electricity supply system that divides an electrical power feed into subsidiary circuits while providing a protective fuse or circuit breaker for each circuit in a common enclosure.
The ring is fed from a fuse or circuit breaker in the consumer unit. Ring circuits are commonly used in British wiring with socket-outlets taking fused plugs to BS 1363 . Because the breaker rating is much higher than that of any one socket outlet, the system can only be used with fused plugs or fused appliance outlets.
The energy is mainly dependent on current and time for fuses as well as the available fault level and system voltage. Since the I 2 t rating of the fuse is proportional to the energy it lets through, it is a measure of the thermal damage from the heat and magnetic forces that will be produced by a fault end.
In electrical engineering, IEC 60269 is a set of technical standards for low-voltage power fuses. [1] The standard is in four volumes, which describe general requirements, fuses for industrial and commercial applications, fuses for residential applications, and fuses to protect semiconductor devices.
Conversion of per-unit quantities to volts, ohms, or amperes requires a knowledge of the base that the per-unit quantities were referenced to. The per-unit system is used in power flow, short circuit evaluation, motor starting studies etc. The main idea of a per unit system is to absorb large differences in absolute values into base relationships.
Because of the presence of a neutral fuse, and in the event that it blew, the neutral conductor could not be relied on to remain near ground potential; and, in fact, could be at full line potential (via transmission of voltage through a switched-on light bulb, for example). [5] Modern electrical codes generally do not require a neutral fuse.
Eventually cubits and strides gave way to "customary units" to meet the needs of merchants and scientists. The preference for a more universal and consistent system only gradually spread with the growth of international trade and science. Changing a measurement system has costs in the near term, which often results in resistance to such a change.
In an electrical power distribution system, a ring main unit (RMU) is a factory assembled, metal enclosed set of switchgear used at the load connection points of a ring-type distribution network. It includes in one unit two switches that can connect the load to either or both main conductors, and a fusible switch or circuit breaker and switch ...