A lighting mast is a fixed or portable structure that raises one or more lights above the work area to illuminate a large site. It is used at construction sites, mines, ports, yards, and temporary work areas. Mast height, aiming, stability, power supply, and glare control affect the result. Raising the lights increases the area that can be covered and can reduce shadows from equipment, but it also increases exposure to wind and may create glare over a wider area. The mast and luminaires should be positioned for the task, aimed carefully, and secured for the site conditions. Portable units may include a generator or battery supply.