Differences Between Metal Enclosed and Metal Clad Switchgear
In the world of electrical power systems, air insulated switchgears are two commonly used types as metal enclosed and metal clad switchgears. While they may appear similar, there are significant differences in terms of their design, functionality and applications. Understanding these differences is crucial for engineers and professionals working with electrical systems. The switchgears are defined in the IEC 62271-200 standard.
In this comprehensive guide, we will explore the distinctions between metal enclosed and metal clad switchgears, their features and the factors to consider when choosing the right type for your specific needs.
Metal Enclosed Switchgear
Definition
According to the standard set by the International Electrotechnical Commission (IEC) a metal enclosed switchgear typically denotes a form of distribution or switching equipment that comprises a metal enclosure housing the components for power distribution or switching operations. This enclosure is crafted to house. Safeguard the components from environmental elements like dust, moisture and physical harm while also ensuring personnel safety by preventing inadvertent contact with live parts.
Metal enclosed switchgear consists of circuit protection devices such as circuit breakers, power fuses, fusible switches as control and metering equipment. These devices can be installed in shared compartments without requiring barriers or compartmentalization as needed in metal clad switchgear.
Features
Metal enclosed switchgear is designed to provide a cost-effective solution for medium-voltage applications. Metal-enclosed switchgear is a type of electrical distribution equipment that comprises various components such as circuit breakers, disconnector switches, busbars, and associated control, monitoring and protection devices. These components are housed within a grounded metal enclosure, typically made of steel sheet.
The metal enclosed swithcgears have AFL internal arc classification, PI partition class and LSC-2A loss of service continunity class according to IEC 62271-200 Standard.
Metal Clad Switchgear
Definition
Metal clad switchgear, a subset of metal enclosed switchgear, is also enclosed in a metal shell on all sides. However, it differs from metal enclosed switchgear in that all internal components are individually clad in metal and compartmentalized. Each component may be insulated and grounded individually, offering enhanced safety features and the ability to access specific compartments without affecting the overall system.
Metal clad switchgear provides additional safety features due to its compartmentalization. Operators can access each component individually, minimizing the risk of injury. The failure of one part of the system does not affect other parts, ensuring system reliability. While maintenance in metal clad switchgear takes longer due to the individual compartmentalization, it allows for targeted maintenance without shutting down the entire system.
Features
The metal clad swithcgears have AFLR internal arc classification, PM partition class and LSC-2B loss of service continunity class according to IEC 62271-200 Standard.
Differences between Metal Enclosed and Metal Clad Switchgear
Understanding the differences between metal enclosed and metal clad switchgear is essential for choosing the most suitable option for your specific application. The following factors distinguish these two types:
Enclosure Configuration
Metal clad switchgear has separate enclosures for each component, while metal enclosed switchgear has a single enclosure for all components. Metal clad switchgear’s compartmentalized design allows for individual access to components, enhancing safety and reducing the risk of system failures.
Compartmentalization
There are cablo connections, circuit breaker, current and/or voltage transformers, earthing switch in the switching compartmet of metal enclosed switchgears. So accessible once the panel is opened to the switching compartment. In contrast, metal clad switchgear compartmentalizes each component in the different compartment. So allowing for targeted access and maintenance without affecting the overall system.
Accessibility
Metal enclosed switchgear provides easy access to all components when the panel is opened. In metal clad switchgear, operators can access individual compartments, avoiding potentially dangerous components while working on others.
Service Continuity
The metal enclosed swithcgears have AFL internal arc classification, PI partition class and LSC-2A loss of service continunity class according to IEC 62271-200 Standard.
Under the LSC2A classification the circuit breaker busbar compartment or single bar system can remain energized even when an accessible compartment is open. However to reach the circuit breaker compartment safely the power to the cables must be grounded. This precaution ensures that personnel can work within the compartment without any risk of shock or harm.
On the hand the LSC2B classification requires a level of service continuity and involves at least three compartments; one for the main switching device one for connection purposes and one for the busbar. In this configuration circuit breakers housed in their compartments can undergo maintenance without having to disconnect cable connections. This setup ensures continuity while adhering to safety standards.
Available Fault Current
The available fault current is another important consideration when choosing between metal enclosed and metal clad switchgear.
Metal enclosed switchgear is suitable for systems with smaller loads and lower fault currents. Low voltage power circuit breakers and metal enclosed interrupters are ideal for these applications, providing adequate protection for transformers.
Metal clad switchgear is designed for systems with higher available fault currents. The circuit breakers used in metal clad switchgear allow for better coordination within the electrical system, offering enhanced protection and control.
Safety Aspects
Safety is a critical factor when selecting switchgear for electrical systems. Both metal enclosed and metal clad switchgear offer different safety features.
Metal enclosed switchgear provides protection against accidental contact with live parts by enclosing each compartment in a metal housing. The circuit breaker compartment is usually separate from the busbars, ensuring safety during maintenance and operation.
Metal clad switchgear offers additional safety features due to its compartmentalized design. Operators can access individual compartments without exposing themselves to hazardous components. Furthermore, the compartmentalization protects other parts of the system in case of a failure, minimizing potential risks.
Area of Use
Metal clad switchgear is specifically designed to operate efficiently in demanding environments, where factors such as high electrical loads, harsh weather conditions, and the presence of dust, moisture, or corrosive elements can pose operational challenges. This specialized switchgear is constructed with sturdy and durable materials, ensuring its resilience in the face of these challenges, making it an ideal choice for applications in power plants, transportation and mining industries, utility substations, and industrial facilities.
Metal-enclosed switchgear is well-suited for systems characterized by smaller loads and lower fault currents, making low-voltage power circuit breakers the ideal choice for such applications. Meanwhile, metal-enclosed breakers are typically employed in medium-voltage setups, particularly in simpler systems where a combination of switchgear and fuses suffices to ensure adequate protection for transformers.
On the other hand, metal-clad equipment is specifically designed to accommodate systems with higher fault currents. Within metal-clad switchgear, circuit breakers offer enhanced coordination capabilities within the electrical system, ensuring efficient and reliable operation even under demanding conditions.
Metal enclosed and metal clad switchgear are two distinct types with unique features and applications. When selecting the right switchgear for your electrical system, consider factors such as available fault current, safety requirements, maintenance procedures, and space limitations. Metal enclosed switchgear is suitable for lower loads, while metal clad switchgear is ideal for higher loads and increased safety. Alternatively, a hybrid approach combining both types can offer a customized solution.
Consult with an expert, Aktif Elektroteknik, to determine the most suitable switchgear for your specific needs.
