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Which type of conduit wiring is used for gas tight explosive proof installation?
Light gauge conduit
Heavy gauge screwed conduit
Both a & b
None of these
Heavy gauge screwed conduit
Heavy gauge screwed conduit is the mandatory standard for hazardous, gas-tight, and explosive-proof electrical installations. These conduits utilize threaded joints that prevent the propagation of arcs or sparks from the electrical circuit to the external explosive atmosphere, ensuring the entire system remains sealed and pressure-resistant.
Heavy gauge screwed conduit is the mandatory standard for hazardous, gas-tight, and explosive-proof electrical installations. These conduits utilize threaded joints that prevent the propagation of arcs or sparks from the electrical circuit to the external explosive atmosphere, ensuring the entire system remains sealed and pressure-resistant.
PburstтАЛ=D2тЛЕSтЛЕtтАЛ тАФ representing the burst pressure capacity of conduit pipe where S is tensile strength, t is wall thickness, and D is diameter.
The principle relies on the 'flame-proof' or 'explosion-proof' enclosure philosophy. By using heavy-gauge steel pipes with precision-cut threads, the conduit forms a continuous, gas-tight mechanical barrier. If an internal ignition occurs, the robust threads and heavy wall thickness dissipate the heat and quench the flame before it reaches the external environment, preventing a secondary explosion.
Used in refineries, chemical plants, and oil storage areas.
Must comply with IS: 2148 / IEC 60079 standards for flameproof equipment.
Threaded joints ensure electrical continuity and mechanical strength.
Eliminates the risk of igniting flammable vapors in hazardous zones.
High mechanical impact resistance
Excellent thermal dissipation for arcs
Prevents internal gas ignition from spreading
High material and installation cost
Requires skilled labor for threading and installation
Significant structural weight
Petrochemical refineries
Grain handling facilities
Hazardous gas storage terminals
| Feature | Light Gauge | Heavy Gauge |
|---|---|---|
Mechanical Strength | Low | High (Rigid) |
Joint Type | Slip-in/Crimped | Threaded/Screwed |
Light gauge conduits are only suitable for domestic and general commercial wiring where mechanical protection requirements are minimal.
Screwed conduits provide better earth continuity compared to grip-type or thin-wall systems.
B is correct тАФ Heavy gauge screwed conduit is essential for hazardous environments as it provides the structural integrity and gas-tight sealing required to contain internal explosions.
In competitive exams, always link 'Gas-tight' or 'Flameproof' requirements to 'Heavy Gauge' and 'Threaded' mechanical interfaces, as these are the defining characteristics of hazardous-zone electrical compliance.