Low voltage is generally referred to as “LV” in the industry. Low voltage switchgear, considered the heart of electrical systems, ensures the safe, efficient, and controllable management of energy. This product group is indispensable for the continuity and safety of the system in both industrial facilities and residential and commercial buildings.
What is low-voltage switchgear?
Low-voltage (LV) switchgear refers to electrical equipment components used to provide energy distribution, control, and protection in low-voltage electrical systems below 1000 Volts. These components include fuses, circuit breakers, contactors, relays, capacitors, buttons, signal lamps, power analyzers, and similar control elements. They ensure the safe, efficient, and sustainable operation of systems in both residential and industrial settings. LV switchgear is an indispensable part of electrical panels and ensures that energy reaches the correct point in the correct way.
What is low voltage?
Low voltage (LV) encompasses voltage levels of 1000 volts and below. Commonly used single-phase 220 VAC and three-phase 380 VAC or 400 VAC systems in Turkey also fall into this category. Even though solar inverter outputs in solar power plants are 800 VAC, low-voltage equipment is used up to 1000 VAC. All protection, control, and switching equipment used in these systems is called low-voltage switchgear.
Commonly Used LV Switchgear
- Automatic Circuit Breakers (MCBs)
An automatic circuit breaker (also called miniature circuit breakers or automatic switches in the literature) is defined as a circuit element that protects the components it is connected to in a protection circuit against overcurrents and short circuits. In the event of an overcurrent and/or short-circuit current in an electrical circuit, automatic circuit breakers provide reliable protection by interrupting the circuit current.
- Residual Current Devices (RCCB/RCD)
Residual current devices detect leakage currents caused by phase-neutral imbalance in the circuit and reliably protect the electrical equipment connected to them. They interrupt the circuit by detecting leakage currents to ensure safety.
- Compact Circuit Breakers (MCCBs)
They provide protection at higher current capacities than automatic circuit breakers. Compact circuit breakers are used up to 630 Amperes. Compact circuit breakers, which can trip thermally and magnetically, are widely used, especially in industrial transfer panels.
- Open Type Circuit Breakers (ACB)
These are high-power switching elements preferred in applications of 630A and above, especially in main distribution panels and transfer panels. Varieties capable of providing protection up to 6300 Amperes are manufactured.
- Load Disconnectors
Used to mechanically open/close the circuit. These are elements that do not switch under load and provide isolation.
- Contactors
Contactors are devices that remotely switch on and off loads such as fans and pumps powered by electric motors. They usually work in conjunction with a thermal relay. Although the triggering voltage varies, the operating voltage is generally 400 VAC.
- Thermal Relays
Used in conjunction with contactors, they prevent motors from being damaged by overcurrent. They protect the windings of electric motors from overheating and burning out.
- Motor Protection Circuit Breakers
These are switches specifically designed for electric motors and provide thermal-magnetic protection. It provides overcurrent and short-circuit protection for electric motors. Used in conjunction with contactors and thermal relays, it forms protection and control systems for electric motors.
- Timer Relays
They perform switching operations with a programmable delay. Although used in low-voltage panels, they are most commonly used in automation systems.
- Miniature Relays
These are small-sized relays used in electrical distribution panels, automation and signal systems, capable of controlling large loads with low current.
- Reactive Power Relays
These are programmable relays that keep reactive power balanced by automatically switching capacitors on and off in compensation systems.
- Capacitors
They correct the power factor (cosφ) of the system by meeting the reactive power requirement. They are a fundamental element of compensation panels.
- Rotary Switches
These are small switches mounted on the panel, used for manual phase change, direction change, or load redirection.
- Low Voltage Busbar Systems
These are copper or aluminum conductor systems that provide the distribution and direction of electrical current within the panel.
- Power Analyzers
They enable system monitoring by measuring values such as voltage, current, frequency, power factor, active and reactive power. They are crucial for energy efficiency monitoring.
- Signal Lamps and Buttons
Located on the front surface of the panels. Buttons activate and deactivate the systems they control, while signal lamps provide status information via LED lights and provide necessary controls for user intervention.
- Current Transformers
Low-voltage current transformers are measuring elements generally used in systems below 1000 Volts that reduce high current values to lower levels that can be read by measuring instruments. These transformers work together with meters, protection relays, and energy monitoring systems to ensure both consumption monitoring and system safety. They typically provide 5A or 1A output and are suitable for panel mounting. Their compact structure saves space in low-voltage panels, while their accurate measurement is critical for energy management and billing.
Applications of Low Voltage Switchgear
Low voltage switchgear is commonly used in the following areas:
Low voltage power distribution panels
Industrial plant automation
Residential and office fuse boxes
Building and automation systems
Power generation plants
Renewable energy plants
Compensation panels
Generator and UPS output panels