The Weights and Measures Act 1985 (Amendment) and Units of Measurement Regulations 1986 (Amendment) Regulations 2019 No. 1211

Amendment of the Weights and Measures Act 1985

2.  In the third column of the table in Part 7 of Schedule 1 to the Weights and Measures Act 1985(1) (definitions of units of measurement of electricity)—

(a) for the definition given for “AMPERE” substitute—

“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 Δv_Cs, 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) in the definition given for “WATT”, after “joule”, insert “, where the second has the meaning given in the definition of “AMPERE””.

(1)

1985 c.72.