# S.I. No. 154/2020 - European Communities (Units of Measurement) (Amendment) Regulations 2020

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I, HEATHER HUMPHREYS, Minister for Business, Enterprise and Innovation, in exercise of the powers conferred on me by
section 3
of the
European Communities Act 1972
(No. 27 of 1972) and for the purpose of giving effect to Council Directive 80/181/EEC of 20 December 1979 | ||||||||||||||||||||||||||||

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1. (1) These Regulations may be cited as the European Communities (Units of Measurement) (Amendment) Regulations 2020. | ||||||||||||||||||||||||||||

(2) These Regulations come into operation on 13 June 2020. | ||||||||||||||||||||||||||||

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2. In these Regulations— | ||||||||||||||||||||||||||||

“Principal Regulations” means the European Communities (Units of Measurement) Regulation 1992 ( S.I. No. 255 of 1992 ); | ||||||||||||||||||||||||||||

3. Section 1.1 of Schedule 1 of the Principal Regulations is replaced by the following— | ||||||||||||||||||||||||||||

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Definitions of SI base units: | ||||||||||||||||||||||||||||

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The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency Δ | ||||||||||||||||||||||||||||

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The metre, symbol m, is the SI unit of length. It is defined by taking the fixed numerical value of the speed of light in vacuum | ||||||||||||||||||||||||||||

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The kilogram, symbol kg, is the SI unit of mass. It is defined by taking the fixed numerical value of the Planck constant | ||||||||||||||||||||||||||||

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The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge | ||||||||||||||||||||||||||||

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The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant | ||||||||||||||||||||||||||||

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The mole, symbol mol, is the SI unit of amount of substance. One mole contains exactly 6,022 140 76 * 10 | ||||||||||||||||||||||||||||

The amount of substance, symbol | ||||||||||||||||||||||||||||

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The candela, symbol cd, is the SI unit of luminous intensity in a given direction. It is defined by taking the fixed numerical value of the luminous efficacy of monochromatic radiation of frequency 540 * 10 | ||||||||||||||||||||||||||||

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Celsius temperature T and T_{0} where T_{0} = 273,15 K. An interval or difference of temperature may be expressed either in kelvins or in degrees Celsius. The unit “degree Celsius” is equal to the unit “kelvin”.’ | ||||||||||||||||||||||||||||

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GIVEN under my Official Seal, | ||||||||||||||||||||||||||||

01 May, 2020. | ||||||||||||||||||||||||||||

HEATHER HUMPHREYS, | ||||||||||||||||||||||||||||

Minister for Business, Enterprise and Innovation. | ||||||||||||||||||||||||||||

EXPLANATORY NOTE | ||||||||||||||||||||||||||||

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These Regulations are made to give effect to Council Directive No. 2019/1258/EU of the European Parliament and of the Council of 23 July 2019 on the approximation of the laws of Member States relating to units of measurement. | ||||||||||||||||||||||||||||

The main changes in the Regulations provide for new definitions of the SI base units. The new definitions are based on the new principle of fixed numerical values of the defining constants and are expected to improve the long-term stability and reliability of the SI base units as well as the accuracy and clarity of measurements. | ||||||||||||||||||||||||||||

1 Council Directive 80/181/EEC of 20 December 1979 on the approximation of the laws of the Member States relating to units of measurement and on the repeal of Directive 71/354/EEC (OJ L 39, 15.2.1980, p. 40) |