Special Occupancies and Equipment Flashcards
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Read the first 7 Special Occupancies and Equipment flashcards as text
Under NEC Article 501 for Class I locations, seals in conduit systems are required within how many inches of an arcing or sparking device enclosure?
Answer: 18 inches
NEC 501.15(A)(1) requires sealing fittings within 18 inches of an enclosure containing ignition-capable equipment in Class I, Division 1 locations.
NEC Article 553 covers floating buildings. What is the minimum size service conductor permitted for a floating building service?
Answer: Size per calculated load; no separate minimum
NEC 553.5 requires floating building services to be sized per the load calculation; no separate minimum conductor size beyond standard load-based sizing applies.
For signs and outline lighting covered by NEC Article 600, all metal parts of sign enclosures must be grounded. What is the maximum ground conductor resistance permitted?
Answer: No resistance limit specified; must meet bonding requirements
NEC Article 600 does not specify a maximum resistance value; it requires metal parts to be bonded in accordance with standard grounding and bonding requirements in Article 250.
In a place of assembly under NEC Article 518, which wiring method is specifically permitted in areas where the building is of fire-rated construction?
Answer: MI cable and metal-enclosed wiring systems
NEC 518.4(A) requires metal-enclosed wiring methods such as MI cable, metal raceways, or metal-clad cable in fire-rated construction within places of assembly.
Per NEC 547.9, the disconnecting means for agricultural buildings must be located outside the building or inside near the point of entry. What is the maximum number of disconnects permitted as the service disconnecting means?
Answer: 6
NEC 230.71 permits a maximum of six disconnects as the service disconnecting means, which also applies to agricultural buildings under Article 547.
Under NEC Article 626, electrolytic cells used in industrial processes must have their DC power supply disconnecting means able to de-energize the cell circuits within what maximum time?
Answer: Instantaneous
NEC 626.12 requires that the disconnecting means for electrolytic cell lines be capable of de-energizing them quickly enough to protect personnel, which means it must operate instantaneously.
NEC Article 501.105 specifies that luminaires in Class I, Division 1 locations must be marked to show the maximum wattage lamp permitted. Why is this marking required?
Answer: To prevent overheating that could ignite the surrounding atmosphere
Overlamping a hazardous location luminaire can raise surface temperatures above the ignition temperature of flammable gases, so maximum wattage marking prevents this hazard.