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Single phase power transmission took many years to develop. The earliest developments were based on the early alternator inventions of 19th century Parisian scientist Hippolyte Pixii, which were later expanded upon by Lord Kelvin and others in the 1880s. The first full AC power system, based on single phase alternating current, was created by ...
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 volt-ampere (SI symbol: VA, [1] sometimes V⋅A or V A) is the unit of measurement for apparent power in an electrical circuit. It is the product of the root mean square voltage (in volts) and the root mean square current (in amperes). [2] Volt-amperes are usually used for analyzing alternating current (AC) circuits.
Single-pole circuit breakers feed 120 V circuits from one of the 120 V buses within the panel, or two-pole circuit breakers feed 240-volt circuits from both buses. 120 V circuits are the most common, and used to power NEMA 1 and NEMA 5 outlets, and most residential and light commercial direct-wired lighting circuits.
Central heating differs from space heating in that the heat generation occurs in one place, such as a furnace room or basement in a house or a mechanical room in a large building (though not necessarily at the geometrically "central" point).
An electric heater is an electrical device that converts an electric current into heat. [1] The heating element inside every electric heater is an electrical resistor , and works on the principle of Joule heating : an electric current passing through a resistor will convert that electrical energy into heat energy.
For example, if the load power factor were as low as 0.7, the apparent power would be 1.4 times the real power used by the load. Line current in the circuit would also be 1.4 times the current required at 1.0 power factor, so the losses in the circuit would be doubled (since they are proportional to the square of the current).
Furnaces, electric water heaters, heat pumps, central air conditioning units, electric dryers, electric stoves or cooktops, and built-in microwave ovens must be on dedicated circuits. The code provides rules for sizing electrical boxes for the number of wires and wiring devices in the box.