Voltage power and current, where 1 volt = 1 watt (of power) per 1 ampere (of current). This definition is equivalent to the more commonly used 'joules per coulomb'. Voltage or electric potential difference is denoted symbolically by , but more often simply as "V", for instance in the context of Ohm's or Kirchhoff's circuit laws. Electric potential differences between points can be caused by electric charge, by electric current through a magnetic field, by time-varying magnetic fields, or some combination of these three. A voltmeter can be used to measure the voltage (or potential difference) between two points in a
Electrical wiring in the United Kingdom 1, 1.5, 2.5, 4, 6 and 10 mm. Sizes of 1 or 1.5 mm are typically used for 6 or 10 ampere lighting circuits and 2.5 mm for socket circuits. The earthing conductor is uninsulated since it is not intended to have any voltage difference from surrounding earthed articles. Additionally, if the insulation of a or neutral wire becomes damaged, then the wire is more likely to earth itself on the bare earth conductor and in doing so either trip the RCD or burn the fuse out by drawing too much current. Earthing and Bonding are used together to provide