What Is an Explosion-Proof Connector?
Explosion-proof connectors are connectors for electrical connections used in explosive or hazardous environments.
Explosion-proof refers to a structure that prevents explosions or flames. Explosion-proof equipment must be used in factories that handle explosive gases or flammable or volatile liquids. Explosion-proof connectors are designed to prevent sparks or strong electromagnetic radiation that could cause an explosion.
They have the ability to limit sparks in the connector even in the event of explosive gas leakage. Special materials are used to ensure robustness and high durability in explosive environments. Explosion-proof connectors are required to meet specific standards and safety criteria. International standards include ATEX (European), NEC (US), and IECEx (International).
Applications for Explosion-Proof Connectors
Explosion-proof motors are used in chemical plants, mining industry, military, etc.
1. Manufacturing Industry
Explosion-proof connectors are often used in environments under explosive gases generated in the manufacturing process of chemicals and petroleum products. Explosion-proof connectors ensure safe electrical connections to electrical equipment and measuring devices.
2. Mining Industry
In the mining industry, explosive gases and dust may be generated during mining and refining operations in mines. Explosion-proof connectors are therefore required. They are used for lighting, communication systems, motor controls, etc. in mines.
3. Military Facilities
Military facilities often handle explosives. Explosion-proof connectors are therefore widely used. To prevent accidents and fires caused by explosive materials, high safety is required in electrical connections and communication systems.
Principle of Explosion-Proof Connectors
Explosion-proof connectors have a sealed enclosure to prevent the intrusion of explosive gases and dust from the outside. The enclosure is often made of stainless steel or other metal alloys.
It also has a contact area for the transmission of electrical signals. It consists of metal pins and sockets and is characterized by signal stability and low contact resistance. Contacts in explosion-proof connectors use explosion-proof gaps or other means to minimize the risk of explosion.
They may also be equipped with shielding features to prevent external electromagnetic interference and electrostatic effects. In addition, cable grounds are often placed at the connector and cable connections. This controls electrostatic discharge and reduces the risk of explosion.
To prevent sparks and discharges due to incomplete connections, they often have an interlock mechanism. If the connector is not connected properly, the electrical circuit is broken, ensuring safety.
Types of Explosion-Proof Connectors
Explosion-proof connectors’ explosion proof performance is defined by domestic and international standards. They are also classified from Zone 0 to Zone 2 in order of increasing hazard according to the type and amount of hazardous materials handled. The explosion-proof construction required for each area is specified.
The four main explosion-proof structures used are “intrinsic safety explosion-proof structure,” “explosion-proof structure,” “internal pressure explosion-proof structure,” and “safety-enhanced explosion-proof structure.”
1. Intrinsic Safety Explosion-Proof Construction (Symbol I)
This is a structure that has been confirmed not to be an ignition point for explosive spaces in the event of sparks or high temperatures during normal operation or malfunctions.
In Zone 0 areas, control panels and other equipment that are difficult to make intrinsically safe are often installed outside the explosion-proof area. An explosion-proof connector is used for an electrical connection from the control panel.
2. Explosion-Proof Construction (Symbol D)
A sealed structure that withstands the pressure of an external explosion without risk of further ignition. A robust metal casing is used.
3. Internal Pressure Explosion-Proof Construction (Symbol F)
This is a structure in which a protective gas is sealed inside to eliminate the possibility of ignition. Nitrogen gas is used as the storage gas.
4. Safety-Enhanced Explosion-Proof Construction (Symbol E)
This structure is designed to prevent sparks, arcs, and high temperatures. It can be used in Zone 3.