Thomas Percival Pask, son of Thomas Pask and his wife Elizabeth Cole, qualified as electrical engineer and journeyman and immigrated to South Africa in 1895. For some time he worked in the electrical department of the Cape Government Railways before moving to Johannesburg, where he joined the staff of the May Consolidated Gold Mining Company. In May 1897 he became a foundation member of the South African Society of Electrical Engineers and served as its first secretary. Many years later he published a valuable "Historical note of 1897" (Transactions of the South African Institute of Electrical Engineers, 1930, Vol. 21, pp. 240-243) on the affairs of this society.
With the outbreak of the Anglo-Boer War (1899-1902) Pask moved to Durban as a refugee. There he became associated Mr F.W. Mills, then chief electrical engineer of the Natal Government Railways, and assisted him with the installation of searchlights on an armoured train. Subsequently he installed X-ray apparatus in field hospitals in Natal until just before the end of the war. After an overseas visit he was appointed in 1903 as assistant chief electrical engineer of the Natal Government Railways, stationed in Pietermaritzburg. He was transferred to Durban in May 1905 and, after the formation of the Union of South Africa in 1910, was appointed assistant superintendent (electrical and telegraphs) for Natal in the South African Railways. In 1913 he was transferred to Johannesburg and in 1918 was promoted to superintendent. In 1925 he succeeded F.W. Mills as chief electrical engineer, a position he held until his retirement in 1929. After his retirement he joined the Victoria Falls and Transvaal Power Company.
Pask was a member of the South African Institute of Electrical Engineers and took a keen interest in all its work, particularly in the study of lightning and its effects. One of his papers published in its Transactions, 'An introduction to the study of electric traction in Natal' (1926), won the institute's gold medal award. In a paper read before the institute in April 1930, 'An approach to the study of lightning and allied phenomena' he advocated the establishment of a lightning research laboratory. Later that year the institute established a Lightning Investigation Committee, with Pask as chairman, a position he held until 1932. The committee's work eventually led to the formation of the Bernard Price Institute of Geophysical Research. Meanwhile Pask moved to the Cape Peninsula for health reasons.
Pask joined the (British) Institution of Electrical Engineers as an associate member in 1902 and became a member in 1920. He was also for many years a member of the Roentgen Ray Society. In November 1903 he married Ethel Millicent Algar, with whom he had a daughter.