Contractors and supervisors in machining, metal forming, shaping and erecting trades and related occupations supervise and coordinate the activities of workers classified in the following unit groups: Machinists and machining and tooling inspectors (72100), Tool and die makers (72101), Sheet metal workers (72102), Boilermakers (72103), Structural metal and platework fabricators and fitters (72104), Ironworkers (72105), Welders and related machine operators (72106) and Machining tool operators (94106). They are employed by structural, platework and related metal products fabrication, manufacturing and erecting companies and machine shops. Contractors may be self-employed.

Contractors and supervisors in electrical trades and telecommunications occupations supervise and coordinate the activities of workers classified in the following unit groups: Electricians (72200), Industrial electricians (72201), Power system electricians (72202), Electrical power line and cable workers (72203), Telecommunications line and cable installers and repairers (72204) and Telecommunications equipment installation and cable television service technicians (72205). They are employed in a wide range of establishments; places of employment are indicated in the above unit group descriptions. Contractors may be self-employed.

Contractors and supervisors in pipefitting trades supervise and coordinate the activities of workers classified in the following unit groups: Plumbers (72300), Steamfitters, pipefitters and sprinkler system installers (72301) and Gas fitters (72302). They are employed by construction companies, mechanical, plumbing and pipefitting trade contractors and maintenance departments of industrial, commercial and manufacturing establishments. Contractors may be self-employed.

Contractors and supervisors in carpentry trades supervise and coordinate the activities of workers classified in the following unit groups: Carpenters (72310) and Cabinetmakers (72311). They are employed by construction companies, carpentry contractors, maintenance departments of industrial establishments, and custom furniture and fixture manufacturing or repair companies. Contractors may be self-employed.

Contractors and supervisors, other construction trades, installers, repairers and servicers supervise and coordinate the activities of various tradespersons, installers, repairers and servicers classified in the following minor groups: Bricklayers and Insulators (7232), Concrete finishers, tilesetters and plasterers (7310), Roofers, Glaziers, Painters, decorators and floor covering installers (7311) and Building maintenance installers, servicers and repairers (7320). They are employed by a wide range of establishments; places of employment are indicated in the unit group descriptions. Contractors may be self-employed. This unit group also includes prefabricated product installation and service contractors and proprietors of some repair and service establishments.