The Electrician lays out, installs and tests electrical fixtures, and installs electrical wire systems, systems used to provide heat, light, power, air conditioning and refrigeration in homes, office buildings, factories, hospitals, and schools. An Electrician also installs conduit, greenfield and other materials, and connects electrical machinery, equipment and controls in high-rise buildings and installations. Electricians may be required to work at great heights; or may be required to dig deep trenches and cuts for underground installations. The electrical trade is unique in that it is mechanical, technical, and professional. It must select individuals who have a natural aptitude for using tools, and who are gifted enough to master the intricacies of electrical science. They must keep up with the progress of the industry and master a knowledge of the thousands of installation and maintenance procedures.