Weights and Measures Act 1985 (c. 72)

SCHEDULES

SCHEDULE 1 U.K. Definitions of Units of Measurement

Part VII U.K. Measurement of Electricity

1.	(a) AMPERE	[F1 for which the symbol “A” is used, is the SI unit of electric current, defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 × 10-19 when expressed in the unit C, which is equal to A s, where the second is defined by taking the fixed numerical value of the caesium frequency ΔvCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s-1.]
	(b) OHM	is the electric resistance between two points of a conductor when a constant potential difference of 1 volt, applied between the two points, produces in the conductor a current of 1 ampere, the conductor not being the seat of any electromotive force.
	(c) VOLT	is the difference of electric potential between two points of a conducting wire carrying a constant current of 1 ampere when the power dissipated between these points is equal to 1 watt.
	(d) WATT	is the power which in one second gives rise to energy of 1 joule [F2 , where the second has the meaning given in the definition of “AMPERE”].
2.	Kilowatt	= 1000 watts.
	Megawatt	= one million watts.

Textual Amendments

F1 Words in Sch. 1 Pt. 7 substituted (13.6.2020) by The Weights and Measures Act 1985 (Amendment) and Units of Measurement Regulations 1986 (Amendment) Regulations 2019 (S.I. 2019/1211), regs. 1(b), 2(a)

F2 Words in Sch. 1 Pt. 7 inserted (13.6.2020) by The Weights and Measures Act 1985 (Amendment) and Units of Measurement Regulations 1986 (Amendment) Regulations 2019 (S.I. 2019/1211), regs. 1(b), 2(b)