Power Distribution System Flashcards
Automatic Transfer Switch
The automatic transfer switch in a secondary selective system will sense a loss of power from either source and will automatically transfer essential loads and emergency lighting to the hot side.
Branch Circuit
The circuit conductors between the final overcurrent device protecting the circuit and the outlets.
Disconnect
A device which the conductors of a circuit can be disconnected from their source of supply.
Feeder
All circuit conductors between the service equipment or the source of a separately derived system and the final branch circuit overcurrent device.
Grounding Conductors
A conductor used to connect equipment on the grounded circuit of a wiring system to a grounding electrode. The grounding conductor must be bare, green, or green with one or more yellow stripes.
Grounded Conductor
A conductor that is intentionally grounded.
Grounding Electrode Conductor
The conductor used to connect the grounding electrode to the equipment grounding conductor and/or grounded conductor of the service equipment.
Panel/Panelboard
A single panel or group of panel units designed for assembly in the form of a single panel, including buses; automatic overcurrent devices; and with or without switches for the control of light, heat, or power circuits; designed to be placed in a cabinet or cutout box placed in or against a wall or partition and accessible only from the front.
Service
The conductors and equipment for delivering energy from the electrical supply system to the wiring system of the premises served.
Switchgear
Electrical switching devices to energize, deenergize, or “change over” to other paths either manually or automatically.
Tie Breaker
A keyed device that separates the two transmission systems of a secondary selective system. The tie breaker must have two keys and is switched over manually.
Three-Wire / Edison Three-Wire System
A third wire known as the neutral wire is added to the basic two-wire circuit that carries unbalanced current unless the other loads take the same current then it carries no current.
Edison 3-Wire (Single-Phase Power Distribution)
This system has three service entrance conductors with two ungrounded “hot” conductors and the grounded neutral conductor.
Four-Wire Wye
The fourth wire of the four-wire wye system is called the neutral wire and it is electrically connected to ground.
Multiwire Branch Circuits
Circuits that use one grounded conductor (neutral) for two or more, out of phase, ungrounded conductors (Hot wires).
