A Beginner's Guide to Low Voltage Switchgear - Electrical Cabinet

Low-voltage switchgear is a crucial component of electrical systems, providing both safety and control. Understanding the fundamentals is critical for anyone working in electrical engineering or maintenance.

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This guide is intended to provide newcomers with an overview of the essential ideas, components, functions, and applications of low-voltage switchgear, laying the groundwork for further learning.

What is low-voltage switchgear?

A low-voltage switchgear (LV) is a three-phase power distribution unit that can supply electric power at up to 1,000 volts and current at up to 6,000 amps. Often used indoors, these are enclosed in a metal case containing copper conductors and a combination of circuit breakers and isolators. 

Electrical Switchgear Types

There are three different classes of switchgear systems: low-voltage, medium-voltage, and high-voltage.

• High Voltage Switchgears: High-voltage switchgears (HV) are those that control 75KV of power or more. Because these breakers are designed for high-voltage use, they often include improved safety features.
• Medium Voltage Switchgear: Medium-voltage switchgear(MV) is utilized in systems ranging from 1 KV to 75 KV. This switchgear is commonly found in systems that include motors, feeder circuits, generators, and transmission and distribution lines.
• Low Voltage Switchgear: Low-voltage switchgear(LV) is designed to regulate systems up to 1KV. These are often found on the low-voltage sides of power distribution transformers and are employed in a wide range of industries.

Main Components of Low Voltage Switchgear

Low voltage switches, earth leakage circuit breakers, HRC fuses, electrical isolators, air circuit breakers (ACB), moulded case circuit breakers (MCCB), and tiny circuit breakers (MCB) are examples of low voltage switchgear with a 1KV rating.

• Breaker compartment: Devices that automatically cut off electrical flow in the case of an overload or short circuit. Types include tiny circuit breakers (MCBs) and molded case circuit breakers (MCCBs).
• Switches: Mechanical devices for opening and closing electrical circuits. They can be operated manually or automatically.
• Bus compartment: The bus compartment is located behind the circuit breaker compartment and is likewise separated from it by solid barriers.
• HRC fuses: When the current surpasses a certain threshold, safety devices melt and break the circuit. Fuse types include cartridge fuses and plug fuses.
• Enclosures: Protective cases that house the switchgear components, ensuring safety and compliance with standards such as IP ratings for dust and water resistance.
• Cable compartment: The cable compartment, which is located behind the switchgear section, can be divided from the bus compartment using either vented or unvented barriers.
• And other accessories necessary to protect the system

Basic Functions Of Low-Voltage Switchgear Areas

Application of Low Voltage Switchgear

• Power stations
• Transformer stations
• Automotive industry
• Infrastructure
• Machine construction
• Chemicals and petrochemicals
• Pharmaceutical industry
• Oil and gas industry
• Pulp and paper industry
• Cement industry
• Mining industry and steel mills
• Waste disposal
• Water management
• Steel and metal industry
• Glass industry
• Plant construction
• Data centres
• and many more

Benefits of Low Voltage Switchgear

• Keep safe and sound:One of the best things about low voltage switchgear is that it makes things safer by stopping electrical problems and accidents.
• Speed and dependability: It makes sure that electricity systems work well, which cuts down on downtime and boosts efficiency.
• Efficient use of money: Low voltage switchgear saves money in the long run because it keeps equipment from getting damaged and lowers the cost of upkeep.

Low Voltage Switchgear FAQs

What Is The Difference Between Switchgear And Switchboards?

Because switchgear and switchboards may be configured in almost infinite ways, each with features that the other cannot have, it is impossible to compare costs directly across systems that are identical in size and function. Having stated that, an engineer may infer that switchboards are often a far less expensive alternative based on the larger size and quantity of material needed for switchgear with divided compartments, even accounting for the expense of additional functionality and control wire.

Read More:Electrical Switchboard vs. switchgear

Is Low-Voltage Switchgear Easy to Use?

As a switchgear manufacturer, we create custom switchgear that is tailored to the specifications of the building or application for which it is intended, and is often installed in a ‘controlled environment’ such as a plant or switch room.

Some systems are simple to operate while others are quite complicated. We usually recommend that people receive training before operating any LV Switchgear, as making a mistake may be costly or have disastrous repercussions if done properly. We urge that only competent, trained, and certified individuals handle live switchgear, and that personal protection equipment (PPE) be worn when switching devices for one’s own safety.

Low voltage withdrawable switch Cabinet GCK

Enecell is Famous China GCK Low Voltage Withdrawable Switchgear Cabinet Manufacturers,Supplier, GCK series low voltage withdrawable switch cabinet is designed according to the needs of the majority of users. It has the characteristics of compact structure, beautiful appearance, good electrical performance, high protection level, safety and reliability, and convenient maintenance. It is an ideal power distribution equipment for low voltage power supply systems in metallurgy, petroleum, chemical industry, electricity, machinery, textile and other industries. It is listed as a recommended product for two-network transformation and energy-saving product by the state.

GCK combined assembly structure, the cabinet frame is made of hot-rolled steel STHC, FA profiles are positioned by angle plates, bolted, non-welded structure, and the forming dimensions, opening dimensions, and equipment clearances of parts are modularized.

Product Overview

GCK low-voltage withdrawable complete set of equipment is suitable for power supply systems with AC 50-60Hz, rated working voltage up to 660V, and rated current A and below. It is widely used in low-voltage distribution systems in power plants, substations, industrial and mining enterprises, high-rise buildings, etc., as power receiving, feeding, reactive power compensation, power metering, lighting and motor control center, etc., for power conversion, distribution and control.

This product complies with relevant standards such as IEC-1, GB.1 "Low-voltage complete switchgear and control equipment" and GB/T "Low-voltage withdrawable complete switchgear and control equipment".

Product model meaning

Normal Use Environment Conditions

1. The ambient air temperature is not higher than +40℃, not lower than -5℃, and its average temperature within 24 hours is not higher than +35℃. The equipment should be used at reduced capacity when it exceeds the above environment.
2. The relative humidity does not exceed 50% when the maximum temperature is +40℃. A higher relative humidity is allowed at a lower temperature, such as 90% at +20℃. The influence of condensation that may occur accidentally due to temperature changes should be considered.
3. The installation site is usually installed at an altitude of no more than m. For places above m, the capacity should be reduced accordingly.
4. Install in a place without fire, explosion hazard, severe dust, chemical corrosion, severe vibration and impact.
5. If the above conditions cannot be met, the user and the manufacturer should negotiate to resolve.

Main Technical Parameters

With competitive price and timely delivery, AOKEYER sincerely hope to be your supplier and partner.

Note: It is recommended to use a cabinet depth of mm.

Structural Features

This equipment is a combined assembled structure. All the structural parts of the cabinet frame are galvanized (or coated with aluminum zinc plate), equipped with the required doors, baffles, partitions, drawers, mounting brackets, busbars and various electrical components, etc., to assemble a complete control center equipment. Because of the flexible and convenient assembly and the strong versatility of parts, it can meet the requirements of shorter construction period and power supply continuity. The equipment is designed to be operated in front of the cabinet, with outlets behind the cabinet, and maintenance in front and behind the cabinet. According to needs, the cabinet body can be composed of drawer cabinets, fixed cabinets, mixed cabinets, fixed partition cabinets and other combinations.

1. Area division

According to different requirements, each equipment is divided into three compartments, namely functional unit room, busbar room, and cable room. The compartments are separated from each other by steel plates and are independent of each other to effectively prevent accidents caused by arcing caused by faults of switching elements and short circuits between busbars.
1.1 The functional unit room is located in each independent compartment on the front side of the cabinet, which is used to install drawer units or fixed partition units.
1.2 The busbar room is divided into the main busbar room and the distribution busbar room. The main busbar room is located on the top of the cabinet, and the distribution busbar room is located in an independent compartment on the left side behind the cabinet.
1.3 Due to the design of the outlet at the back of the cabinet, the cable room is located at the back of the cabinet.

2. Cabinet

2.1 The basic frame is composed of C-profiles. The C-profile is made of steel plates or aluminum-zinc plates with E=25mm modular mounting holes, which are bent and connected by high-strength bolts. It can be assembled into various forms of cabinets without special tools, and has high strength and flexibility.
2.2 The internal dimensions, component dimensions, and compartment dimensions of the cabinet are modularized. According to different cabinet types or actual needs, the structure and withdrawable units can be arbitrarily combined into cabinets of different specifications and uses.
2.3 The compartments are separated by steel plates, and the upper and lower drawers are separated by partitions with ventilation holes to ensure safety and effective heat dissipation.
2.4 A variety of inlet and outlet cable options are available (upper inlet and upper outlet, lower inlet and lower outlet, upper inlet and lower outlet, lower inlet and upper outlet).
2.5 According to the needs of system control, a control busbar can be set up and installed in a dedicated compartment, which can be laid in the entire system.
2.6 The cable room is used for laying power cables and control cables. It is equipped with primary and secondary wiring terminals and corresponding cable fixings for rear-outlet wiring (the primary and secondary wiring terminals of the rear-outlet solution can be laid out separately to avoid cross wiring). According to the cable specifications and entry and exit methods, entry and exit holes are reserved on the bottom plate or top plate. The compartment design makes it very convenient for cables to enter and exit from top to bottom.

3. Busbar system

3.1 The main busbar can be arranged in an independent busbar room. Each phase consists of a single or multiple copper bars, which are installed horizontally on the top of the cabinet and supported by a high-strength busbar frame, with good dynamic stability.
3.2 The distribution busbar is used to connect the functional unit and the main busbar. Rectangular busbars are selected and distributed in the vertical metal busbar channel. 3-phase or 4-phase distribution busbars can be installed as needed. After the drawer unit is pulled out, the protection level of the vertical busbar can reach IP20.
3.3 Neutral busbars and main grounding busbars are installed in the cabinet, which are installed under the cabinet. The length of the busbar is determined by the transportation unit of the equipment. The neutral and grounding branch busbars are installed vertically in the cable room behind the cabinet, and are equipped with standard modulus holes for cable connection.
3.4 The busbars are all made of TMY-T2 series hard copper bars. The surface of the copper bar can be tinned, silvered and anti-oxidized as needed to improve the dynamic thermal stability of the busbar and improve the temperature rise of the contact surface.

4. Functional units

4.1 Drawer-type functional units
4.1.1 The height of a single-layer drawer unit is 200mm, and it is divided into five size series: 8E/4, 8E/2, 8E, 16E, and 24E. The rated current of the unit circuit is 630A or less.
4.1.2 Each drawer cabinet can be installed with a maximum of 9 single-unit drawers, 18 8E/2 unit drawers, or 36 8E/4 unit drawers.

Drawer unit size

4.1.3 The drawer unit has 5 positions, including closing (connection) position, opening position, test position, withdrawal/advance position, and isolation position. The drawer unit can be accurately positioned by the operating handle (8E/4, 8E/2) or the operating handle (8E and above). Each position has a corresponding mark, which is simple and intuitive. The operating handle can be equipped with a padlock to lock it in the corresponding position to avoid misoperation.
4.1.4 Each drawer unit is completely independent and the drawers are completely isolated. When the drawer unit is withdrawn, the main power supply of the equipment does not need to be cut off. The drawer can be pushed/pulled out without powering off the adjacent drawer units, and there will be no risk of electric shock.
4.1.5 The drawer unit adopts a JG type rotary push operating mechanism, which uses a spiral trajectory to move along the positioning piece to complete the push and pull of the drawer unit, and realizes four-position display and mechanical interlocking at the same time. It is equipped with a micro switch that can be electrically interlocked in the test position to avoid personal injury or equipment accidents.
4.1.6 During operation, it is possible to set parameters or check the internal conditions of the drawer unit. If the drawer panel needs to be opened, the front panel of the drawer unit can be opened with the corresponding tools.
4.1.7 The drawer changes only in height, and its depth remains unchanged. The same drawer unit has complete interchangeability. The drawer unit plug capacity configuration is detailed in the table below.

4.1.8 The drawer unit is equipped with an instrument panel for installing metering, measuring, operating, indicating and other devices
A: The operation of the main switch of the 8E/4 and 8E/2 drawer units is achieved by a handle installed on the instrument panel.
B: The instrument panel of the 8E and above drawer units remains in place when the front panel is opened and closed.
4.1.9 The primary outlet side is directly connected to the fixed outlet adapter, and the secondary outlet side is connected through a dedicated secondary connector. The number of secondary connectors of the 8E/4 drawer unit is up to 16 cores, the number of secondary connectors of the 8E/2 drawer unit is up to 20 cores, and the number of secondary connectors of the 8E and above drawer units is up to 24 cores.
4.1.10 The drawer unit adopts corresponding guide rails to guide the entry, exit and positioning of the drawer unit. The guide rails are equipped with anti-drop devices to effectively prevent the drawer from sliding when pulling the drawer unit.
4.2 Fixed-separation functional unit (based on fixed, plug-in, and withdrawable components)
4.2.1 This functional unit retains the advantages of simple structure and convenient operation of fixed units, and has the characteristics of clear separation and reliable isolation of drawer-type functional units, which is particularly suitable for high-current PC unit applications.
4.2.2 When plug-in or withdrawable components are withdrawn for maintenance or replacement, there is no need to cut off the power supply. The use of such components can ensure that when maintaining the equipment, only the components of the corresponding circuit need to be withdrawn without affecting other circuits of the entire distribution system.
4.2.3 The functional unit is interlocked with the rotary handle on the panel through the operating mechanism, which can ensure that the panel of the functional unit can only be opened when the circuit breaker is in the open state, thereby enhancing the safety of equipment operation.
4.2.4 When the equipment is running, if you need to set parameters or check the internal components of the unit, you can use the corresponding unlocking tool to open the front panel.

Ordering Instructions

When ordering, users should provide the following information:
1. Feng circuit scheme diagram and primary system diagram.
2. Auxiliary circuit electrical schematic diagram and terminal arrangement diagram. If there is no schematic diagram and terminal arrangement diagram, follow the manufacturer's standard.
3. Equipment arrangement and combination diagram and floor plan.
4. Model, specification and quantity of main electrical components in the equipment.
5. Inlet and outlet line mode and cable specifications. If busbar connection is required between equipment or incoming line unit, busbar span, height from the ground and other data should be provided.
6. Surface color of the equipment.
7. Other special requirements should be negotiated with the manufacturer.

Application Case

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