Arc Splitters / Deion Plates

Arc splitters, also known as deion plates, are metallic components installed inside the arc chute or arc extinguishing chamber of electrical switching devices such as circuit breakers and contactors. Their primary function is to rapidly extinguish the electric arc that forms when contacts separate under load. They achieve this by physically splitting the arc into multiple shorter and cooler series arcs, which increases the total arc voltage beyond the system voltage, forcing the current to zero. Simultaneously, the plates act as heat sinks, cooling the arc plasma, and provide surfaces that promote recombination of ions and electrons, effectively deionizing the arc path to prevent re-strike. These plates are typically made from galvanized steel, stainless steel, or copper alloys, and are available in thicknesses ranging from 1.5 to 3.0 mm with dimensional tolerances of ±0.1 mm. They are designed for rated voltages from 400 to 690 V AC and rated currents from 16 to 630 A, with breaking capacities up to 50 kA. Arc extinguishing times typically range from 10 to 30 ms. The plates operate within a temperature range of -40°C to 120°C and a humidity range of 5% to 95% RH (non-condensing). Insulation resistance is at least 100 MΩ at 500 V DC, and dielectric strength is at least 20 kV/mm. The material grade for insulating parts is DMC/SMC per GB/T 1303.2. These values are reference ranges and must be verified for the specific model and application with the legal manufacturer or supplier. Standards such as IEC 60947, IEC 60664, IEC 60068, IEC 60112, IEC 60243, and ISO 2768 are referenced for testing and verification.

When an arc is drawn between separating contacts, it is driven into a stack of closely spaced metallic plates (the arc splitters). The arc root attaches to a plate, then splits and re-forms across the gaps to the next plate, creating a series of shorter arcs. Each split arc has its own anode and cathode voltage drop, summing to a total arc voltage that exceeds the system's recovery voltage. The metal plates absorb thermal energy, cool the arc plasma, and provide a conductive path for charged particles to recombine, extinguishing the arc.