Service entrance equipment, also known as service entrance devices (SED), is an essential part of an electrical system that connects a building or structure to the electrical utility’s power distribution network. It serves as the entry point for electrical power into a residential, commercial, or industrial facility. Here are the key components and functions of service entrance equipment:
- Service Drop: The service drop is the overhead electrical line that connects a building to the utility’s power lines on the utility pole or overhead lines. It typically consists of conductors supported by a messenger wire or cable.
- Service Lateral: In some cases, especially for underground electrical distribution, the service lateral is used instead of a service drop. The service lateral is an underground electrical line that runs from the utility’s distribution network to the building’s service entrance.
- Service Entrance Conductor: These are the electrical conductors that run from the point of connection (service drop or lateral) to the service entrance equipment on the building. The size and type of conductors are determined by the electrical load requirements of the building.
- Weatherhead: The weatherhead is a weatherproof fitting mounted on the exterior of the building where the service drop enters. It protects the service entrance conductors from environmental factors like rain and wind.
- Service Entrance Mast: In some installations, a service entrance mast is used to support the weatherhead and service entrance conductors. It extends above the roofline to provide clearance and secure attachment for the service drop.
- Meter Base: The meter base houses the electrical utility’s electric meter, which measures the amount of electricity consumed by the building. It provides a secure and weatherproof enclosure for the meter.
- Main Service Panel (Load Center): The main service panel, also known as a load center or distribution panel, is a large electrical enclosure located inside the building. It contains circuit breakers or fuses that protect individual branch circuits and serves as the main point of distribution for electrical power to various parts of the building.
- Main Disconnect Switch: In some installations, a main disconnect switch is installed between the meter base and the main service panel. This switch allows for the complete disconnection of electrical power to the building in case of emergencies or maintenance.
- Grounding Electrode System: The grounding electrode system ensures electrical safety by providing a path for electrical faults and lightning to dissipate safely into the ground. It typically includes ground rods or other grounding electrodes and conductors.
- Service Entrance Cable or Conduit: The service entrance conductors are typically routed through a service entrance cable or conduit. This protects the conductors from physical damage and provides a clean, organized installation.
- Service Entrance Bonding: Proper bonding and grounding of the service entrance equipment are crucial for electrical safety and to prevent electrical shock hazards. Bonding ensures that all metal components are at the same electrical potential.
- Utility Demarcation Point: The demarcation point is the point of separation between the utility’s responsibility and the building owner’s responsibility for electrical service. It is usually located at the service drop or lateral connection.
Service entrance equipment is a critical part of any electrical system, as it ensures safe and reliable electrical power distribution to a building while complying with local electrical codes and regulations. Proper installation, maintenance, and inspection of this equipment are essential to electrical safety and reliable service.