(19)

(11)

EP 0 489 834 A1

(12)

(43) Date of publication: 17.06.1992 Bulletin 1992/25 (21) Application number: 90913501.0 (22) Date of filing: 31.08.1990

(51) International Patent Classification (IPC):  H05B 3/ 00( . ) H05B 3/ 74( . ) H05B 3/ 44( . ) (86) International application number: PCT/GB1990/001346 (87) International publication number: WO 1991/003915 (21.03.1991 Gazette 1991/07)

(84) Designated Contracting States: BE CH DE ES FR GB IT LI NL (30) Priority: 31.08.1989 GB 19890019700 (71) Applicant: Electricity Association Services Limited London SW1P 4RD (GB)	(72) Inventors: BLUNDY, Robert, William Clwyd CH7 4QW (GB) DRISCOLL, John, Lionel South Wirral L66 1HQ (GB) EATON, Donald, James Heswall Merseyside L61 9PP (GB) JONES, William Clwyd CH7 1XL (GB) (74) Representative: Cross, Rupert Edward Blount, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)