In intrinsically safe apparatus, sealing conduits and cables is to minimize passage of gases, vapors, or dusts.

• A. minimize passage of gases, vapors, or dusts
• B. to prevent ignition
• C. to block moisture
• D. to improve signal integrity

Answer: (A)

Sealing conduits and cables in intrinsically safe equipment is about preventing ingress of hazardous atmospheres into the enclosure. By minimizing the passage of gases, vapors, or dusts, you keep any potentially explosive mixture from forming inside the equipment, so the internal electrical components remain in a non-ignitable environment even if the outside atmosphere is hazardous. This specific action supports the overall safety aim of intrinsic safety by reducing opportunities for ignition.

While preventing ignition is the broad safety goal of intrinsic safety, sealing is the particular measure that controls what can enter the enclosure. Blocking moisture isn’t the primary purpose here, and improving signal integrity isn’t related to the safety objective of ingress control.