ABSTRACT
In this chapter we look at the electrical scientifi c principles and competencies required of a qualifi ed electrician.
Very early units of measurement were based on the things easily available – the length of a stride, the distance from the nose to the outstretched hand, the weight of a stone and the time-lapse of one day. Over the years, new units were introduced and old ones modifi ed. Different branches of science and engineering were working in isolation, using their own units, and the result was an overwhelming variety of units.
