Introduction
-A branch circuit is any segment of a wiring system extending beyond the final automatic over current protective device that is approved for use as branch circuit protection & designated by the NEC as the branch circuit protective device.-Branch circuits generally originate in panel boards, but individual branch circuits to motors commonly originate at individual fused switches or C.B. tapped from bus ways.
-In an electrical system, the branch circuits are the circuits of lowest capacity and current rating. They are the circuits to which load devices (light, motors, etc….) are connected.
-A branch circuit consists of two wires, which carry current at a particular voltage from protective device to utilization device. Although the branch circuit represents the last step in the transfer of power from the service or source of energy to the utilization devices. It is the starting point for modern design procedures.
-Each & every branch circuit , whether for a power or lighting load in a commercial, industrial, or residential building , should be sized for its load, with spare capacity added where possible load growth is indicated .
-The rating of the circuit fuse or C.B. must not be less than 125% of the continuous current load.
General
A branch circuit consists of two wires, which carry current at a particular voltage from protected device to utilization device. Although the branch circuit represents the last step in the transfer of power from service or source of energy to the utilization devices, it is the starting point from modern design procedures.The definition of branch circuit
The circuit conductors between the final over current device protecting the circuit and the outlet (load).
Branch circuit layout
General purposes of branch circuit
Branch circuit that is supplies two or more outlets for lighting and other equipment.Individual branch circuit
Branch circuit that is supplies only one utilization equipment.
An individual branch circuit, which supplies only one utilization equipment via a single receptacle
Multi wire branch circuit
It is consists of two or more ungrounded conductors that have voltage between them and grounded conductor have equal volt between it and each ungrounded conductor in the circuit and it is connected to neutral and the grounding of the system.Rating of branch circuit
The rate of branch circuit can be indicated according to the maximum current of the circuit, and also the over current protective device will be rated according to the maximum current of branch circuit.The wiring conductor must be withstanding the current pass through it The rate of branch circuit based to the rate of over current protective device.
The electrical requirements for place have equipment or devices
Receptacles, switches, lamp-holders, dimmers, pilot lamp and home automatic control the receptacles can be supplied from different nominal voltages which one half of the receptacles supply by line to neutral voltage and another half supply by line to line voltage and this type of receptacle called split wired receptacle The branch circuit which supply the receptacle must have an over current protective device such as two pole circuit breakers or single pole circuit breakers which handle Tie.
Combination receptacle
Combination receptacle and switch
Ungrounded conductors
If multi-wire branch circuit supplied from different nominal voltages the under grounded conductors in multi-wire branch circuit shall be identified by separated colour coding, marking tape, tagging and shall be permanently posted at each branch circuit panelboard.
Multi-conductor armored cable
Branch circuit panelboard
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