The U.S. National Electrical Code for Switchboards

Electrical switchboards are power supply equipment and are a major component used in power distribution. The main purpose of this component is to transfer power from one power supplying source to another. It is made up of a number of panels. Each of these panels contains switches that distribute power to electronic devices. The U.S. National Electrical Code, NEC, specifies that each switchboard must be a single large panel or a combination of panels. Each of these panels should contain switches, buses and other controlling devices mounted on front or back of the panels. Switches mounted on these panels are basically used to redirect power to other power distribution channels. Switches also let the consumer control the flow of power. Other uses of switches include regulating power supplied to the devices, protecting electrical devices from damage caused by high voltage.

Generators to the Switchboard

Power is supplied to electric switchboards by a power generator or some other power source. Internally switchboards contain several busbars made up of copper and covered by insulators. These copper strips play an important role in distributing power from switchboards. The power supplied to and distributed from an electric board must be balanced. The amount of power supplied to the board from a power generator should be equal to the amount of power distributed by the switchboard. Load sharing buses, plus gauges and other devices mounted on the board help in controlling this supply and distribution process.

Switchboard Classifications and Ratings

switchboards are classified into several types depending on interrupt rating, insulating medium, voltage, current rating, operating methodology, construction, and type of application. An important function of the electric board is to supply correct amount of power to each and every electrical device connected to the board. The amount of power required by the device is calculated based on the device. The board receives power from a major source like a generator and is supplied to various devices connected to the board. The amount supplied depends on the status of the device connected. If the device is turned off, less amount of power should be supplied to prevent any damages from electrocution. Whenever the connected device becomes active, full power should be supplied to the device.

Switchboard ratings are important in letting an installer or operator know what the max current requirement is. This is also an indicator of the available fault current. The most commonly utilized rating method is known as the full rating method. This method is more expensive because it requires the use of circuit breakers with ratings which are higher or equal to the available fault current.

Proper precautions must be taken before working on maintenance of switchboards. Bare busbars are a major source of power supply and may cause electrocution when not handled properly. It is always advised to use gloves, glasses, rubber mats, and shoes if you plan to work on a live switchboard.