One significant element of power system design is to select the right distribution equipment. Based on the design of the power system and different other criteria one amongst the switchgear and switchboard is chosen. Switchgear and switchboard both of these two systems are used to redistribute electricity to other electrical equipment or power circuit, but their structures are fabricated and tested to different standards. The type of the circuit breakers used in the system marks the key difference between the switchgear and switchboards.
The three different sorts of circuit breakers are available in several interrupting ratings. However, initial installation cost also pays a crucial role in the selection process, the price between a high-end distribution switchgear and low-end switchboard differs a lot and requires to be assessed against issues of reliability, maintainability, and downtime.
An insight on switchboards
Electric switchboard directs electric current from one end to another source. Each of the panels is integrated with switches that allow electricity to be redirected. The switchboard is immensely helpful in protecting the technician and other operators from possible electrocution or shock. The switches control the amount of current that passes into the switchboard and they are fed from generator featuring AC frequency as well as load sharing controls. Prior to open the switchboard for maintenance, it is crucial to separate the power, as the busbars are bare. The electrolyzed busbars are a strong source of power and while working on energized live switchboard, taking important precautionary measure is highly essential. Hence, the technicians must be ready with the protective equipment like gloves, thick rubber mats while working on an open switchboard.
Now let’s have a look at different sorts of circuit breaker out there in the market
Molded case circuit breakers
This sort of breakers is commonly referred as MCCBs and widely used in panel boards and switchboards. The voltage ratings in this type of circuit breakers generally range from 15-3000 amps. Here the breaker mechanism is completely sealed within the external molded case. When the breaker has problem or failure, it needs to be replaced. The breakers are usually bolted onto the bus or may be integrated with plug-in designs. The addition or removal of MCCBs to a switchboard must be performed after turning off the power source of the switchboard.
Insulated case circuit breakers
Insulated case breakers or ICCBs is designed to offer features usually available in power circuit breakers. The voltage ratings range from 400-5000 amps. This sort of breakers is available as additional options in switchboards and designed to the similar standards as MCCBs, they offer access to replaceable parts like contacts.
Power circuit breakers
Here the voltage ratings range from 800-5000 amps, the power circuit is tested under different standards from the ICCBs and MCCBs. They are connected to the bus in a draw out design enabling the breakers to be withdrawn fully or partially while the entire switchgear is powered on. PCBs is integrated with numerous components which can be replaced, inspected like pole assemblies, contacts, and arc chutes.
Complexity and project type often dominates the selection; naturally, a manufacturing facility is much different in comparison to the office facility. However, the most viable way of selecting the right switchgear system is to consult with high voltage engineers.