An electrician in Lisbon is a tradesman specializing in electrical wiring of buildings, stationary machines and related equipment. Electricians may be employed in the installation of new electrical components or the maintenance and repair of existing electrical infrastructure. Electricians may also specialize in wiring ships, airplanes, and other mobile platforms. Electricians are typically not allowed to perform work for the public unless under the employment of an electrical contractor. The job of an electrician is a regulated trade for safety reasons due to the many hazards of working with electricity, requiring testing, registration, or licensing. Licensing of electricians is controlled through government and/or professional societies in Lisbon.