What are underground installations typically composed of?

Underground installations are broadly composed of various types of utilities designed to provide essential services. This includes not only sewer and water lines, which are critical for sanitation and water supply, but also electric lines for power, gas pipelines for fuel, and telecommunication lines for communication services. By encompassing all these utilities, the answer recognizes the diverse range of installations that may be found underground. Understanding this comprehensive definition is important for excavator operators, as it highlights the need for caution and awareness when digging, as multiple types of utilities could be present, leading to potential hazards if they are unintentionally disturbed.