Charles James Monk, electrical engineer, attended public schools in East London and at Rockcliffe, near Grahamstown, and then trained at the Electrical Training Institution at Faraday House, London, for three and a half years. Subsequently he worked for the mechanical engineering firm Fielding and Platt in Gloucester and the Southport Corporation Electricity Works. From 1907 to 1910 he was employed in the electrical accessories and testing departments of British Insulated and Helsby Cables, Ltd., England.
In June 1910 Monk returned to South Africa to take up the position of assistant testing engineer with the Victoria Falls and Transvaal Power Company. He was promoted to testing engineer in January 1917. In March 1935 he was transferred to head office in Johannesburg as assistant engineer (electrical) and promoted to consumers' engineer in September 1936, a post he held until his retirement at the end of January 1952.
Monk became a member of the South African Institute of Electrical Engineers in March 1907, served as a member of its council from 1924, and was elected president for 1933. In addition to his presidential address and valedictory address he contributed the following papers to the institute's Transactions: 'Relay protective devices' (1917), 'Some aspects of protective apparatus for electrical machinery' (with N.D. Penny, 1924), and 'The use of protective relays on alternating current systems' (1932). In 1933 he and his colleague Frank Edward Rendell were granted a United States patent for the automatic isolation of parallel three-phase electric power transmission lines.
Monk was a strong supporter of the South African Standards Institution and was a member of its Electrical Engineering Committee from its inception until the work of the institution was taken over by the Bureau of Standards during the years 1946-1951. He served as chairman of the committee in 1934.
He was married to Dorothy Natalie Tonkin, with whom he had two daughters. After her death in 1948 he married Elinor Mary Hogan.