This consolidated version of IEC 60061-1 is based on the third edition (1969) and its supplements A(1970), B(1971), C(1972), D(1972), E(1972), F(1975), G(1977), H(1977), J(1980), K(1983), L(1987), M(1989), N(1992), P(1994) Q(1994), R(1995), S(1996), T(199