Internal arc power testing in electrical panels

In industrial facilities, where reliable power supply is essential, electrical safety becomes a cornerstone of operational continuity. Among the various risks present in low and medium voltage systems, internal arc flash is one of the most dangerous phenomena, capable of generating temperatures exceeding 20,000 °C, releasing destructive pressure waves, and endangering both equipment and the physical integrity of people.

To ensure that electrical panels can withstand these extreme conditions, type tests are performed, with the internal arc test being one of the most important. These tests simulate, in a controlled manner, critical situations that may occur in the field, validating the robustness of the design and ensuring the protection of the most important asset: human life.

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What are type tests?

Type tests are standardized procedures performed on prototype electrical panels to verify that they meet the requirements established in national and international technical standards. Unlike routine tests, which individually verify each piece of equipment before delivery, type tests evaluate the overall performance of the design under electrical, thermal, and mechanical stress conditions.

Among the most common tests are those for temperature rise, dielectric strength, short circuit, degree of protection, and the internal arc test, which stands out precisely because of its relevance in protecting people.

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What is an Inner Arch rehearsal?

The internal arc test is a test performed to evaluate the ability of an electrical panel to contain the destructive effects of an electric arc generated within its structure. During the simulation, extremely high fault currents are applied, causing an arc to form inside the panel.

The objective of the test is to verify if the equipment can contain the thermal and mechanical effects, preventing doors from being projected, metal parts from being thrown, or hot gases from reaching the external environment. To validate the safety of nearby people, fabric markers are used around the panel, representing operators.

If these markers are not burned and the casing maintains its integrity, the panel is considered approved.

This type of test follows technical recommendations such as IEC TR 61641, applied to low-voltage assemblies, and IEC 62271-200, aimed at medium-voltage panels.

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What generates an internal arc?

An internal arch can originate from different factors, including:

• Loosening of electrical connections over time, caused by thermal expansion;

• Accumulation of dust or conductive particles inside the panels;

• Electrical insulation failures due to material aging;

• Entry of foreign objects or animals into industrial environments;

• Operational errors or inadequate maintenance.

Regardless of the cause, the consequences can be serious: ranging from irreversible damage to the panel to direct risks to the lives of professionals near the equipment.

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Safety in electrical operation

Performing internal arc tests ensures that electrical panels meet the safety levels required for critical industrial operations. This means that, in the event of a fault, the effects of the arc will be contained within the panel, preserving the integrity of operators and minimizing damage to the electrical system.

Tested and certified panels not only increase operational reliability, but also bring greater peace of mind to engineers and managers, who know they are dealing with equipment designed to withstand extreme conditions.

Furthermore, relying on tested solutions is also a regulatory compliance requirement, ensuring adherence to international standards and avoiding legal or technical liabilities that could compromise operations.

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Internal arcing is one of the most critical occurrences in low and medium voltage electrical systems, but its risks can be controlled with technology, quality engineering, and properly tested equipment.

Internal arc type testing represents a safety milestone for any industrial project, proving that the panels are capable of withstanding extreme events and, above all, protecting lives.

At BTM, we develop tested and certified electrical panels that undergo rigorous validation processes in leading laboratories, such as CEPEL. In this way, we guarantee that each solution delivered to our clients meets not only technical requirements, but above all, our commitment to safety, reliability, and efficiency in electrical operations.

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