Requirements for round and square bar not less than 10 mm diameter or across flats; rectangular bar not less than 2.5 mm minor dimension and extruded round tubes and sections for electrical conductors in aluminium in two conditions and aluminium alloy in one condition. Tolerances on dimensions and corner radius, chemical composition, mechanical properties and electrical resistivity. Preferred sizes for rectangular bar, extruded tube and round bar are given.Cross References:BS 18:Part 1BS 1499BS 1728BS 3239 BS 3660Partially replaced by Parts 3-6 of BS EN 755 but remains current.Incorporates the following:AMD 3379 published 30 June 1980