What is Metal Clad? What does it do, how does it work and what features does it have?

Metal clad refers to a special switchgear structure used in medium voltage switchgear systems that collects the main electrical components in separate metal compartments. Briefly, the answer to the question of what is metal clad is; It is a medium voltage panel system designed with a focus on security and ease of maintenance, providing physical separation between busbars, breaker, measurement elements and cable connection sections. This structure is widely preferred, especially in critical facilities, as it offers higher partitioning and access control than classical compact solutions.

The best answer to the question of what metal clad is for is not just about turning the energy on and off. These systems; It ensures the protection, control, measurement and safe operation of medium voltage circuits. It also helps limit the effects in the event of a malfunction, controlled access to certain sections during maintenance, and safer decommissioning of equipment. Therefore, the metal clad structure is not just a panel, but a distribution and protection solution with strong security logic.

The most important feature of metal clad systems is the partition structure. In these structures, the main busbar compartment, circuit breaker compartment, cable connection compartment, measurement transformer or auxiliary equipment compartments are separated from each other by metal separators. Thus, work to be done or a problem that may occur in one section does not mean direct open access to other sections. This approach significantly improves both operational safety and maintenance discipline.

To explain the question of how metal clad works simply; The medium voltage energy coming from the network reaches the busbar system, is controlled through the circuit breaker in the relevant cell and is transferred to the cable or load feed on the output side. In this process, measurement transformers, protection relays, auxiliary circuits and cable terminations also serve in the relevant sections. But the important difference is that each critical section is separated from each other, and this separation increases the service security of the system.

When metal clad structure is mentioned, withdrawable circuit breaker system usually comes to mind. In this type of designs, the breaker can be operated in different situations such as service position, test position and reserved position. Thus, the breaker can be moved in a controlled manner without dismantling the entire cell for maintenance or testing operations. This feature is one of the most important practical advantages of metal clad systems and significantly increases the ease of maintenance.

Metal clad and metal enclosed systems are frequently confused. Although they are both metal-enclosed switchgear solutions, the main difference between them is the level of partitioning. In metal enclosed structures, some equipment may be located in common compartments. In metal clad construction, the concept of separate metal compartments is much more evident. Therefore, metal clad solutions are considered to be more advanced in terms of security, maintenance and access control.

This structure is especially preferred in industrial facilities, energy production plants, large commercial buildings, critical infrastructures, facilities with high process dependency and substations. This is due not only to electrical performance but also to operational reliability. Metal clad systems provide serious advantages in places with high short circuit levels, where outages are expensive or where maintenance discipline is important.

In metal clad panels, the protection system is often relay-based. Because the circuit breakers used in these structures are generally medium voltage vacuum or similar switching elements, and their protection logic works with relays, measurement transformers and auxiliary circuits. Therefore, the metal clad system is not just mechanical partitioning; It also means a well-designed protection and control infrastructure.

One of the security advantages of metal clad construction is controlled access. Access to the cable compartment, busbar compartment or breaker compartment is not random. Thanks to door interlocks, mechanical locks, test positions and operating sequences, personnel are prevented from accessing the wrong section at the wrong time. For this reason, metal clad systems stand out especially in facilities where high security discipline is required.

Arc resistant designs, that is, internal arc resistant designs, are also an important topic mentioned together with metal clad systems. Not every metal clad panel is automatically arc resistant; However, this technology is often applied on metal clad structures. The aim is to limit the internal arc energy directed towards the operator and to make the effect of the event more controlled. For this reason, when choosing a project, it is necessary to evaluate the concepts of metal clad and arc resistant without mixing them.

When choosing a metal clad, rated voltage, rated current, short-circuit breaking capacity, short-term withstand current, cell layout, supply structure, busbar system, withdrawable breaker need, protection relay architecture and maintenance approach should be evaluated together. It is not right to make a selection based only on the number of cells. Because the metal clad system must meet both today's loads and future operating scenarios.

In these systems, cable headers, measurement transformers, grounding scheme, auxiliary DC/AC feeds and secondary cabling are at least as important as the main busbar and breaker. Although the metal clad panel looks compact and orderly from the outside, multiple subsystems work together inside. Therefore, a good metal clad solution consists not only of quality cell body; It consists of the harmonious design of all the equipment inside.

In summary, metal clad; It is a panel structure with separate metal compartments developed to provide security, partitioning, ease of maintenance and controlled operation in medium voltage switchgear systems. The withdrawable breaker arrangement is a powerful solution in critical facilities thanks to its relay protection, controlled access logic and high application reliability. If metal clad switchgear selection, MV panel modernization, breaker-relay coordination and field operation safety will be evaluated together in your facility. HV/MV testing, maintenance and repair with LV/MV/HV project design and consultancy services can support the technical decision process.