Electric Power Distribution

Natural Gas Distribution, Water Supply and Irrigation Systems, Sewage Treatment Facilities, Steam and Air-Conditioning Supply, Water and Sewer Line and Related Structures Construction

Hydroelectric Power Generation

Water Supply and Irrigation Systems, Sewage Treatment Facilities, Steam and Air-Conditioning Supply, New Single-Family Housing Construction (except Operative Builders), New Multifamily Housing Construction (except Operative Builders)

New Single-Family Housing Construction (except Operative Builders), Residential Remodelers, Masonry Contractors, Air-Conditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration Equipmen

Water Supply and Irrigation Systems, Sewage Treatment Facilities, New Single-Family Housing Construction (except Operative Builders), New Multifamily Housing Construction (except Operative Builders), New Housing Operative Builders