Understand commonly used terms for electric and gas utilities

The following are common terms for overhead electric systems.

Cross arm. Usually made of wood, horizontal brackets mount on the power pole. Wires are then attached to conduct electricity.

Insulator. Glass or porcelain fixtures atop the pole that insulate conductors and the current they carry from returning to the ground.

Primary distribution line extension. The high voltage or input side of a transformer. It includes the circuit that feeds into the transformer.

Riser. Pole-installed, this piece connects underground distribution facilities to overhead facilities.

Secondary distribution line extension. The output side of a transformer and its connected circuit. The voltage it delivers is between 0 and 750 volts. It is also known as service delivery voltage.

Service drop. The wire that connects the weather head on your roof to the electric pole. PG&E maintains the service drop; you maintain your weather head.

Transformer. Device that takes the high voltage from distribution and turns it into lower voltage that you can use. Most overhead transformers are secured to wood poles. Overhead high voltage cables connect them to your service meter. We use green steel cabinets for underground transformers, mounted to concrete pads. They’re connected to your service meter by underground high voltage cables.

Weatherhead. Periscope-like structure on your roof that’s made of metal conduit. It’s where your electric service and our overhead service drop line connect.

PLEASE NOTE: Voltage regulators, capacitor banks and reclosers are not transformers.

The following are common terms related to residential overhead electric systems.

Circuit breaker. Device that shuts down the flow of electricity if you unexpectedly overload your circuit, and the current goes over its preset limit.

Electric panel. Located on your property this service center contains fuses, breakers and meters.

Ground Fault Circuit Interrupter (GFCI or GFI). Device that can prevent electric shock when you have wall plugs close to water, like in a bathroom, garage or kitchen. They are available as outlets or breakers.

Main switch. Device designed to protect your equipment installed past the meter.

Weatherhead. This periscope-like structure, made of metal conduit, is where your electric service and our overhead service drop line connect. It’s typically located on your rooftop.

The following are common terms for temporary overhead electric service.

Customer-owned temporary service pole. Poles that PG&E does not own, operate or maintain.

Weatherhead. This periscope-like structure, made of metal conduit, is where your electric service and our overhead service drop line connect. It’s usually on your rooftop.

The following are common terms for residential gas service.

Branch service. Another source of supply for your service, other than a gas main.

Gas houseline. Measuring 1 to 3/4 inch in diameter, small pipes that run out of the meter and onto your property, carrying natural gas to home appliances.

Service delivery point and gas meter. Exact location on your property where PG&E supplies service. An example is your electric meter or gas meter.

Service line or pipe. Pipelines, valves and fittings that carry natural gas from the main distribution to a building’s gas meter.

The following are common terms for residential underground electrical equipment.

Cabling. The conductors, connectors and switches for primary, secondary, and service installations. Cabling may also include cable-in-conduit.

Circuit breaker. Device that shuts down the flow of electricity if you unexpectedly overload your circuit and the current goes over its preset limit.

Conduit. Ducts, pipes or tubes made from a variety of approved materials used to protect electric wires and cables during installation. PG&E uses a variety of conduit. We may also use pull wires and concrete encasement.

Electric panel. Located on your property, a service center that contains fuses, breakers and meters.

Electric Service Extension. Extension of electric service from the main energy supply line to your facility.

Ground Fault Circuit Interrupter (GFCI or GFI). Device that can prevent electric shock when you have wall plugs close to water, like in a bathroom, garage or kitchen. They are available as outlets or breakers.

Main switch. Device designed to protect your equipment installed past the meter.

Service delivery point and electric meter. The exact location on your property where PG&E supplies service. Examples are your electric meter or gas meter.

Splice box. Device found in underground systems that is used to enclose splices in cables, making them readily available for repair.

The following are common terms for temporary electrical service.

Cabling. The conductors, connectors and switches for primary, secondary, and service installations. Cabling may also include cable-in-conduit.

Conduit. Ducts, pipes or tubes made from a variety of approved materials used to protect electric wires and cables during installation. PG&E uses a variety of conduit. We may also use pull wires and concrete encasement.

Electric panel. Located on your property, this service center contains fuses, breakers and meters.

Ground rod. Grounding that provides an electrical connection between non-current-carrying metallic parts of equipment and the earth to prevent or limit an overload of power from lightning, line surges and contact with higher voltage lines. Installation follows the National Electric Code (NEC).

Splice box. Device found in underground systems that is used to enclose splices in cables, making them readily available for repair.

A franchise area is our legal right to occupy public streets, roads, highways and other public places under franchise agreements in place with the agency that has jurisdiction. Following are common terms for franchise area electrical equipment.

Electric distribution lines. Overhead and underground lines including the poles, power lines, substations and transformers that belong to PG&E, supplying at least two services to homes and businesses.

Gas distribution mains. Mains, service connections and equipment that carry or control the supply of natural gas from the local supply point to and including the meter.

Protective structures. Fences, sound barriers, retaining walls, posts, barricades and other structures installed to help protect our distribution equipment.

Transformer. Device that takes the high voltage from distribution and turns it into lower voltage that you can use. Most overhead transformers are secured to wood poles. Overhead high voltage cables connect them to your service meter. We use green steel cabinets for underground transformers, mounted to concrete pads. They’re connected to your service meter by underground high voltage cables. 

Trench. To dig or excavate with the purpose of providing more than one service. Trenching may involve these services:

• Gas
• Electricity
• Cable television
• Telephone

Find more technical information about connecting to the PG&E system. Visit Electric and Gas Service Requirements.

Learn more about setting up new service for electric or gas. Visit Application for Service Process.