{
  "url": "https://openlegislation.uk/weights-and-measures-act-1985/schedule-1/part-VII",
  "json_url": "https://openlegislation.uk/weights-and-measures-act-1985/schedule-1/part-VII.json",
  "legislation": "ukpga/1985/72",
  "legislation_title": "Weights and Measures Act 1985",
  "legislation_url": "https://openlegislation.uk/weights-and-measures-act-1985",
  "path": "schedule/1/part/VII",
  "kind": "part",
  "number": "VII",
  "heading": "Measurement of Electricity",
  "text": "1.\n(a) AMPERE\nfor 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.\n(b) OHM\nis 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.\n(c) VOLT\nis 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.\n(d) WATT\nis the power which in one second gives rise to energy of 1 joule , where the second has the meaning given in the definition of “AMPERE”.\n2.\nKilowatt\n= 1000 watts.\nMegawatt\n= one million watts.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [
    {
      "type": "F",
      "label": "F1",
      "text": "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)"
    },
    {
      "type": "F",
      "label": "F2",
      "text": "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)"
    }
  ],
  "outstanding_effects": [
    {
      "type": "omitted",
      "affecting": "ukpga/2025/20",
      "affecting_title": "Product Regulation and Metrology Act 2025"
    }
  ],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/ukpga/1985/72/schedule/1/part/VII",
    "retrieved_at": "2026-10-29T09:59:41.980135+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}