5 Must-Have Features in a low voltage switchgear

28 Apr.,2025

 

LV/MV Switchgear : Ultimate Guide - D&F Liquidators

Switchgear refers to an amalgamation of electrical switching devices whose function is to switch, control, meter, regulate, isolate, and protect electrical circuits and equipment. Some of the products encompassed within the switchgear include switches, circuit breakers, switch fuse units, contractors, H.R.C. fuses, offload isolators, and earth leakage circuit breakers (E.L.C. Bs). These devices are assembled in a logical manner to form the switchgear. The switchgear may be used to clear faults downstream as well as de-energize equipment so that work can be done. This equipment has direct linkage reliability of the supply of electricity.

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Components of Switchgear

Switchgear comprises protecting and switching devices that include fuses, switches, circuit breakers, isolators, control panels, relays, current transformers, potential transformers, control panels, and other associated equipment.

Some of the equipment is designed to operate under abnormal and normal conditions. Some of the equipment is also designed only to serve the role of switching; hence cannot sense faults. Switchgear facilitates switching generators, distributors, transmission lines as well as other electrical equipment on or off.

In the event of failure on any part of the system such as a short circuit, heavy current flows through the equipment, thus posing a potential threat to the equipment as well as causing interruption of service. When this happens, the switchgear will detect the existing fault before disconnecting the unhealthy section from the rest of the system.

Evolution of the Switchgear

The switchgear is mainly used to interrupt and switch currents under abnormal or normal operating conditions. The simplest form of switchgear that you can find is the tumbler switch that is not only used in controlling and protecting lights but other equipment in the office or at home as well. In the case of circuits that have a higher rating, a high rupturing capacity (H.R.C.) fuse and a switch may be used to protect and control the circuit. Even then, switchgear may not be profitable in high voltage systems of up to 33kV because of two reasons:

  • The fuse cannot interrupt large fault currents resulting from faults within the system successfully.
  • If the fuse blows, replacement may take a longer time resulting in interruption of service to consumers.

In advanced power systems, the equipment and lines carry high current and operate at high voltage; thus, the occurrence of a short circuit can lead to massive damage. As such, the heavy currents are interrupted by heavy fault currents.

Essential Features of Switch

Here are some of the critical features of switchgear:

  • Complete reliability – Continued interconnection as well as an increase in the capacity of the generating stations call for installation of reliable switchgear. The inclusion of switchgear is paramount to improving reliability. Thus, when there is a fault in the power system, the switchgear must work on segregating the section that is faulty from the rest of the circuit.
  • Quick operation – When faults occur on any section of the power system, the switchgear must operate quickly to prevent damage by short-circuit currents to the transformers, generators as well as other equipment. When a fault is not cleared quickly, it can spread to other healthy areas, thereby endangering the systems to a complete shutdown.
  • Provision for manual control –Reliable switchgear needs to have provision for manual control whereby the important operation can be executed via manual control whenever there is a failure in electrical controls.
  • Absolutely certain discrimination – Whenever there is fault on any part of the power system, the switchgear should be able to differentiate between the healthy section and the faulty section. Consequently, it should be able to segregate the faulty section from the system without having an effect on the healthy section to ensure the continuity of power supply.

Classification of Switchgear

Switchgears are classified according to the voltage level. Thus, there are three main categories of switchgear as follows:

  • High voltage (H.V.) switchgear
  • Medium voltage (MV) switchgear
  • Low voltage (LV) switchgear

Switchgear and Protection

Fuses that can be rewired and low voltage switches are used to close and open the electrical circuit manually in the home where the electrical fuse protects the household’s electrical circuit from short circuit faults as well as over current.

Consequently, electrical circuits that include high voltage electrical power systems require protective devices and switching. However, in extra-high-voltage and high voltage systems, the protective and switching schemes can get too complicated for the high fault current interruption securely and safely.

Additionally, from a commercial viewpoint, electrical power systems require measuring, regulating, and control arrangement. This entire system is collectively referred to as the switchgear and protection of the power system. Thus, electrical switchgear has developed in various forms.

Switchgear protection plays an essential role within the modern network of the power system from generation to transmission and distribution. The device that is used to switch or interrupt the flow of current in the switchgear protection system is referred to as a circuit breaker that may also be operated manually. The circuit breaker senses faulty conditions in the system through protection relay where the relay is actuated by a faulty signal from the voltage transformer or current transformer.

Apart from the power system network, switchgear may also be required in industrial projects, industrial works, commercial and domestic buildings.

LV Switchgear

Low voltage switchgear refers to electrical switchgear that is rated to 1kv. Thus, the term LV switchgear collectively refers to H.R.C. fuses, low voltage circuit breakers, offload electrical isolators, switches, earth leakage circuit breakers, molded case circuit breakers (MCCB) and miniature circuit breakers (M.C.B.). That is, all accessories that are required in protecting the LV system. The LV switchgear is mainly used in the LV distribution board. The system is made up of the following parts:

  • Incomer
  • Sub-incomer
  • Feeders

The Basic Functions of LV Switchgear

The role of the LV switchgear includes the following:

  • Electrical protection – This guarantees protection of the elements of the circuit against mechanical and thermal stress. It also offers protection of persons in case of insulation failure. It protects appliances as well as apparatus that are being supplied with electricity.
  • Isolation of parts of installation – This aims to de-link the circuit apparatus from the rest of the system that is energized to allow the isolated part to be worked on while ensuring safety.
  • Remote or local switching – Switchgear control function gives room for modification of a loaded system by the operating system personnel according to the laid down requirements. It includes functional control, maintenance operations on the power system, and emergency switching.

Working of LV Switchgear

How to inspect, test and measure LV switchgear

Here are some general inspection and maintenance timelines for low voltage switchgear:

  • General inspection should be done annually, paying attention to all the components
  • Motor and starter feeders (outgoing), incomers, and windings should be inspected every four years
  • Voltmeter correctness should be inspected every four years
  • Inspection of compartments of busbars should be done every eight years
  • Ammeter correctness should be done every four years
  • Outdoor equipment conditional assessment should be done every two years

For testing and maintenance of low voltage switchgear, the following timelines must be observed:

  • Feeders (incoming, switches, busbars)
    The operating systems, controlling equipment, interlocks, and protection equipment need to be tested every four years.
  • Busbar systems
    Insulation resistance, bolts for torque resistance, and ductors should be tested every eight years
  • Feeders for the motor
    • Cable tightness and draw out interlocks – every four years
    • Earth fault and thermal fault protection – every four years
    • Thermal protection of category ‘e’ – every 3 years
    • Restarting – every four years
    • Insulation resistance – every four years
  • Feeders (Plain)
    • Tripping – every four years
    • R.C.D. on fixed load (to look out for overheating) – every four years
    • Draw out interlock, cable tightness – every four years

MV Switchgear

A switchgear system that is capable of handling between 3kv and 36kv is referred to as medium voltage switchgear. These come in many types, such as metal-enclosed outdoor type, metal-enclosed indoor type, as well as an outdoor type without metal enclosure, among others.

The mode of interruption of this switchgear can be S.F., oil, and vacuum with the main requirement of the medium power network being interrupting current whenever there is a fault condition regardless of the type of C.B. that is used by the MV switchgear system.

The Functions of MV Switchgear

Medium voltage switchgear should be able to perform the following functions:

  • Short circuit current interruption
  • Switching capacitive currents
  • Switching the inductive currents
  • Performing normal ON/OFF switching
  • Other special applications

Ultimately, all the functions mentioned must be undertaken with a high degree of reliability and safety.

Working of MV Switchgear

How to inspect, test and measure MV switchgear

Different components that make up the MV switchgear need to be inspected as part of the routine maintenance. Usually, the inspection and maintenance take place after a defined period as follows:

  • General inspection – All components need to be checked annually
  • Compartments of busbars – Every eight years
  • Internal cable boxes, internal fuse contractors, internal C.B.’s – Every four years
  • The correctness of voltmeter – Every four years
  • The correctness of the ammeter – Every four years
  • Other measuring systems – After four years

Testing and Maintenance

In terms of testing and maintenance, the acceptable durations after which the system should be subjected to testing and maintenance is as follows:

  • Ductor test – Four years
  • Dielectric strength – Eight years
  • Distance between the contacts (SF6, vacuum) – Four years
  • Category ‘e’ thermal protection – Three years
  • Dielectric oil test – Four years
  • Restarting – Four years
  • Insulation resistance – Four years

Busbar Systems

  • Checking correctness of Kvar, kW and measuring the maximum demands of the system – Four years
  • Insulation resistance, torque resistance, doctors and dielectric strength – Eight years

Restoration

  • Replacement, oil filtering as well as replacing components – When the need arises
  • Greasing all the components of the equipment – Four years

Importance of Routine Checks and Regular Maintenance of Switchgear

When switchgear is installed in an environment that is air-conditioned, well ventilated, and clean, it does not need much maintenance. However, significant inspections are necessary when the plant is shut down. Inspections usually include:-

  • Checking interlock operations
  • Identifying contact wear
  • Observing the overload settings
  • Checking the size of fuses used
  • Looking out for possible overheating
  • Checking for the presence of corrosion or dirt on the components of the switchgear.

A lot of concentration must go into checking protective devices, contact distances of the vacuum bottles, and the oil levels within the circuit breaker to ensure that they are all in line with the specifications of the manufacturer.

Even then, exemptions may be given to the switchgear that operate frequently and whose maintenance is dependent on the overall hours of operation. Additionally, care must be taken to ensure that the MV switchgear insulation and the contractual circuits are in place. The gas-insulated switchgear is another exemption that should be maintained according to the specifications of the manufacturer. Consequently, extensive maintenance should be supervised by the manufacturer. If the switchgear is aged, conditional assessment needs to be done to determine if the devices can operate further.

Where LV/MV switchgear applications are used

Switchgears may be used in different areas that include the following:

  • Industrial power distribution in factories and plants where attention must be paid for overload and surge protection. The switchgear help in ensuring organized and better power distribution in machines within the industrial unit.
  • Solar power generation where regulation of surge and voltage is mandatory as it regulates the flow of electric current from the main unit.
  • Power stations – Main and sub-power distribution units that need protection for the varied electrical connections.
  • Residential power distribution – Switchgears may be installed in residential complexes or places where there is a combination of metal-enclosed and metal-clad switchgear.

Overall, electric energy is a vital part of life. Therefore, electricity distribution must be done in a manner that is secure and safe. Security levels can be maintained at the different distribution units as well as substations through the installation of safety mechanisms and devices. Although numerous mechanisms can help safeguard electrical connections in industrial and residential areas, the use of switchgear is recommended because of its features and functions.

Low Voltage Switchgear Guide: Functions, Structure, Maintenance ...

An electrical switchgear describes a set of electrical devices and appliances that perform the functions of controlling, protecting, and isolating electrical circuits from one another. It does this by removing or mitigating power faults like short circuits and overloads.

The article helps explain the importance of switchgear, its types, low voltage switchgear, its functions, maintenance practices, selection features and criteria, distinguishing features, and more. So, keep learning!

Figure no 1 Low voltage switchgear

1) What is Switchgear?

Switchgear is a set of electrical devices that control, protect and isolate power systems. It consists of Circuit Breakers, Switches, Relays, and Fuses that manage the flow of electricity, mitigate faults, and ensure operational safety. Switchgear is critical in power distribution systems, industrial plants, and commercial buildings for protection against overloads, short circuits, and for ensuring uninterrupted power delivery.

Types of Switchgear

i) Low Voltage (LV) Switchgear: They are used for all types of fuses, circuit breakers and electronic relays in all systems where the voltage does not exceed 1kV, such as in homes and small businesses.

Figure no 2 Voltage switchgear

ii) Medium Voltage (MV) Switchgear: Operates at voltages from 1kV to as high as 36 kV. Its application is in substations and in industrial plants. Including, for example, vacuum circuit breakers and protection relay devices.

iii) High Voltage (HV) Switchgear: Operates at over 36 kV and is used in large power substations and power grids. It allows long-distance transmission of electric power.

Classification Based on Insulating Medium

  • Air Insulated Switchgear (AIS): This type of switchgear is not over-insulated as a result of which its manufacturing cost is low and is widely accepted in many distribution systems.
  • Gas Insulated Switchgear (GIS): This type of switchgear utilizes gas as insulation which allows for a compact and reliably insulated design most suitable for the high voltage market.

Switchgears are very important for every power system because they guard all breakup devices from problematic circumstances, therefore minimizing the outage time. With the appropriate switchgear on, safety as well as efficiency is greatly improved be it in households or factories.

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2) What Is Low Voltage Switchgear?

Switchgear low voltage (LV) is employed for monitoring, protecting, and distributing electrical energy for systems that work below 1 kV. It provides safety and efficiency in industrial, and commercial buildings and infrastructure projects by avoiding overloads, short circuits, and system failures.

Figure no 3 Low voltage switchgear

Honestly speaking, Saipwell’s Indoor AC Switchgear is perfect for all 3.6kV, 7.2kV, and 12kV low-voltage systems, managing 630A to A running at 50Hz frequency. It also takes in three-phase and four-wire or five-wire arrangements for complex power loading. Being IP3X rated, it also blocks dust ingress along with protection against accidental touching to a certain degree, guaranteeing safety and stable operation at the same time.

This switchgear is specially designed for simple installation and maintenance, making it fit for use in industrial plants, powerhouses, and big buildings. It operates in different environments effortlessly for high efficiency while greatly reducing the risk of electrical fires.

3) Main functions and fundamental roles of low voltage switchgear

Low voltage (LV) electrical switchgear is one of the basic requirements for the management and protection of any electrical system with voltage levels lower than 1kV. It enables effective and safe power distribution in different industrial plants, commercial offices, and power stations.

LV switchgear is specialized in the following key aspects:

  • Power Control and Distribution: Supplies power to many residential and commercial circuits with constant voltage.
  • Fault Protection: Automatically disconnects faulty circuits in response to overloads and short circuits, which assists in damage control. They may support three-phase systems as well as four-wire and five-wire systems for easy management of electrical load.

Figure no 4 Functions of low-voltage gear

  • System Isolation: Permits system repairs and maintenance work without bringing down the entire system.
  • Efficient Energy Management: Improves the system’s performance by optimizing power distribution and reducing the loss of energy.

You will find all these features in Saipwell’s switch gears. All of Saipwell’s products are tailored to make your power control safe, reliable, and at the same time cost-effective. Maintaining and managing the power system efficiently makes it helpful and trusted for a variety of applications.

4) Internal structure and components of low voltage switchgear

Structures of low voltage (LV) switchboards are built out of an assembly of parts that perform specific functions for the management and safeguarding of electrical power distribution. Each of them is critical for safety and efficiency.

Main Components

a) Breakers Circuit: These guard the system by breaking the flow of power when there is a short circuit, overload, or any defect in the system.

b) Busbars: They are bars for conductivity for the distribution of power within the switchgear.

c) Manual & powered Switches: Devices for controlling a circuit remotely or at the switchboard.

d) Protection with Relays: Assignment of detecting faults, and ordering a circuit breaker to operate to restrict an area of damage.

e) Control Panel: Users can monitor and control the switchgear through the control panel.

f) Enclosure: Offers physical security. With the help of enclosures dust and unintentional contact are out of reach.

These components enable proper and efficient power distribution among industrial and commercial buildings without compromising safety or stability.

5) Features and advantages of low voltage switchgear

Features:

  • Overcurrent and Short Circuit Protection: Disables power during fault conditions to protect equipment from damage.
  • System Compatibility: Accepts one-phase or three-phase power supply for multiple applications.
  • Enclosure Protection: Frequently constructed IP-rated enclosures protecting from dust ingress, moisture, and unintended contact.
  • High Current Capacity: Withstands current levels of up to A, suitable for industrial and commercial purposes.
  • Modular Design: Expansion, installation, and maintenance are easier with the modular design.
  • Remote Monitoring and Control: Switchgear integrates smart functionalities enabling remote monitoring and control.

Advantages:

+ Increased Safety: Helps in the protection of electrical equipment from faults. This minimizes the risk of fire or damaging equipment.

+ Reliable Performance: Provides seamless power distribution in Industrial and commercial environments.

+ Reduced Downtime: Rapid detection and isolation of faults leads to uninterrupted system performance.

+ Energy Efficiency: Makes better use of electricity and so reduces waste.

6) Maintenance and upkeep of low-voltage switchgear

Over time, low-voltage switchgear requires good maintenance if it is to continue supplying power safely and efficiently. Preventive maintenance works to avoid breakdowns, improve life span, and ensure a dependable performance.

Figure no 5 Maintenance of low voltage switchgear

Key Maintenance Practices

! Routine Inspection: Consistent monitoring helps avoid improper wear and tear, overheating, and the accumulation of dirt. The smooth operation of the equipment and less maintenance is key to minimizing faults.

! Tightening Connections: Overheating and equipment failure tend to occur in machines whose terminals are loose. The tightening of all power-supplied connections promotes uninterrupted and stable production output.

! Cleaning And Dust Removal: Ensuring enclosures are monitored increases protection, but dust collection can cause damage to electrical components and warrants a periodic cleaning to prevent damage.

! Testing And Calibration: Set out schedules for the testing of circuit breakers and protection relays to uphold the reliability of the system during irregularities in electricity.

! Replacing Worn Components: Aging and faulty components should be replaced immediately to avoid switchgear system failures and prolong their lifespan.

Maintaining the low-voltage switchgear regularly will, in turn, eliminate inefficiencies, and unforeseen downtimes, and increase the safety level in an electrical distribution system.

7) Differences Between Medium Voltage and Low Voltage Switchgear

Switchgear is categorized based on the power range they control, as LV and MV switchgear. LV switchgear comprises devices that operate a voltage range from 0-V. MV switchgear comprises devices that operate a voltage range from 1kV to 36kV. Even though both serve the same purpose in energy management, they have differences in their usage, architecture, and maintenance procedures.

Low-voltage switchgear is ideal for industries and commercial setups where safety and reliability are crucial. It ensures efficient power distribution, prevents faults, and provides a stable electrical network. If you want to buy low-voltage switch gears, Saipwell’s switch gears are the best option ever. You can contact us just by a single click here.

Medium voltage switchgear, on the other hand, is used for larger-scale applications where power demand is significantly higher. Choosing the right switchgear depends on system voltage, load requirements, and safety considerations.

8) Differences Between Switchgear and Distribution Panel

Both switchgear and distribution panels have their respective place and use in electrical systems. Switchgear is primarily meant for control, isolation, and protection of electric power, while a distribution panel is meant for submetering electrical energy in a building or other facility.

  • Key Differences
  • Operation: Switchgear brings out protection by isolating and opening the faulty circuit through automatic action. A distribution panel, on the other hand, simply distributes power to different electrical loads.
  • Reasoning for Use: Switchgear can handle low, medium and high voltages, therefore, it is suited for use in large industries. Distribution panels, on the other hand, are used mainly for low-voltage systems.
  • Parts: Switchgear appliances include circuit breakers, fuses, relays, disconnecting switches, etc, which means more safety measures. Distribution panels generally consist of circuit breakers or fuses for several circuits.
  • Reliability and Safety: Switchgear must have more features when it comes to safety before maintenance. Distribution panels offer basic protection and aid against overloads or short circuits, but not to that extent.
  • Applications: The distribution of power in homes and offices takes place via distribution panels as switchgear is heavily utilized in industrial plants, power stations, and substations. These places require a higher and more powerful control.
  • Maintenance: Switchgear needs reliability checks after a set period of time while distribution panels are low maintenance.

Distribution panels and switchgear are both vital components of an electricity system. However, switchgear is more about control and protection while distribution panels are all about power distribution. It is a matter of choosing to focus more on the safety requirements, the voltage levels, or system needs.

9) FAQ

1. How can I extend the life of my switchgear?

Ensuring a reliable environment while actively cleaning, and routinely inspecting connections and components will serve switchgear life the most.

2. How to choose the right low-voltage switchgear for your application?

Safety regulations aside, evaluate the space offered for installation, the provided protection features, voltage rating, and current capacity. You need to take into account the requirements set by your premise’s power distribution and control system to ensure both safety and efficiency.

3. What is the standard for low-voltage switchgear?

The standard that guarantees performance and safety regarding low-voltage switchgear endurance is IEC , and ANSI/NEMA. These set the limits and parameters for construction, testing, and operational standards for reliable protection and power distribution.