© National Terms of Connection (Great Britain)
and ENA 2013

Supply Characteristics

For information


As required by law, the electricity delivered to your premises through our distribution system will normally be at one of the voltages set out below and will have the technical characteristics stated there:

  • At 230 volts nominal: normally a single-phase supply, with a permitted range of voltage variation from plus 10% to minus 6%.
  • At 400 volts nominal: normally a three-phase supply, with a permitted range of voltage variation from plus 10% to minus 6%.
  • At either of the above voltages: the supply frequency will be 50 hertz, with a permitted nominal variation of plus or minus 1%.