Snell was born in Saltash, Cornwall, the only son of Commander John Skinner Snell, RN and his wife Harriet Cleverton and educated at Plymouth Grammar School, Finsbury Technical College and King's College, London.
After working for four years from 1885 with Messrs. Woodhouse and Rawson he was appointed in 1889 a resident engineer at Messrs. Crompton and Co., where he worked on electrical supply projects in London and Stockholm. From 1892 he worked as assistant to General Charles Edmund Webber on electrical supply projects in Kensington and a number of country houses, before entering municipal service in London in 1893 as assistant electrical engineer in St Pancras during the construction of the Kings Road power station. In 1896 he transferred to Sunderland as Borough Electrical Engineer, additionally becoming Borough Tramways Engineer in 1896 after which he converted the tramway system to electric power.
In 1906, he set up in business as a consulting engineer in Westminster, amalgamating with Preece and Cardew to form Preece, Cardew and Snell. During that time he served as an expert witness for the General Post Office in a case involving compensation payments to National Telephone Company, after which he was given a knighthood (in 1914). He also acted as President of the Institute of Electrical Engineers for 1914.
During the First World War he served on a number of committees, including the Munitions Inventions Committee. After the war he left the consulting company (by then Preece, Cardew, Snell and Rider) to advise the government of matters of electrical supply. He helped to set up the Electricity Commission and served as its first chairman from 1919 to 1938, during which time the Central Electricity Board was established, the national grid created and the supply of electricity standardised. He was made GBE in 1925.
- "John Francis Cleverton Snell". Grace's Guide. Retrieved 13 June 2017.
- Ross, H. M. "Snell, Sir John Francis Cleverton". Oxford Dictionary of National Biography (online ed.). Oxford University Press. doi:10.1093/ref:odnb/36178. (Subscription or UK public library membership required.)
- "Obituary Notices-John Francis Cleverton Snell". Journal of the Institution of Electrical Engineers. 83 (504): 898–899. December 1938. doi:10.1049/jiee-1.1938.0250. Retrieved 13 June 2017.
- "Sir John Snell". Electrical Review. McGraw-Hill Publishing Company: 453. 5 September 1914.
- Leslie Hannah (17 June 1979). Electricity Before Nationalisation. Palgrave Macmillan UK. pp. 76–. ISBN 978-1-349-03443-7.
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