What is the significance of 'zone 2' or hazardous location classification in B28?

• A. It defines areas where flammable vapors may be present and determines electrical equipment requirements
• B. It indicates safe, non-hazardous zones
• C. It relates to noise control
• D. It defines temperature limits only

Answer: (A)

Zone classification is about where flammable vapors may be present and how that affects electrical equipment. Zone 2 means flammable vapors are not normally present in the area, but they could appear during abnormal conditions such as leaks or equipment malfunction. Because of that, electrical components and wiring must be rated and installed to prevent ignition in those circumstances. In a flammable-refrigerant system, this leads to using equipment certified for hazardous locations (Zone 2), with appropriate protection like approved enclosures or ignition-proof devices and proper installation practices. It’s not about safe zones under normal operation, nor about noise control or temperature limits alone.