Applies to twist on connecting devices for connecting two or more unprepared rigid/and/or flexible copper conductors (the total cross sectional area of the connected conductors not exceeding 35 square mm). Covers low voltage circuits up to 1,000 V a.c. and 1,500 V d.c. where electrical energy is used for household and similar purposes. Coverage includes definitions, marking, construction, mechanical strength, and resistance to heat.