Work in Hazardous (Classified) Locations
Hazardous (classified) locations are covered by the National Electrical Code in articles 500 through 516. Any equipment installed in such an area must be protected using one of the protection methods in sections 500.7 or 505.8, such as the intrinsically safe (IS) protection method provided in 500.7(E) and 505.8(C). How well do you understand these protection methods?
1. Which of the following is a component of the fire triangle?
2. All intrinsically safe (IS) apparatus and associated ones are required to be listed.
3. Generally, how many services are permitted for a building or structure?
Each building or structure served shall be supplied by one service. Note there are several allowances for more than one, but the question deals with general rules.
4. Suitability of identified equipment shall be determined by which of the following?
5. Which of the following wiring methods are suitable for intrinsically safe circuits?
6. A control drawing is required for IS apparatus, associated apparatus and IS system wiring.
Section 504.10(A) requires use of the associated control drawing.
7. If there is no separating partition or barrier, what is the minimum distance for IS conductors from noncircuits?
8. If two or more services are installed at a building or structure as may be permitted in 230.4(A), they are all required to connect to the same grounding electrode system.
9. All equipment and conductors required by the NEC must be listed.
10. The special occupancy requirements in Chapter 5 of the NEC shall not modify or supplement the general requirements in chapters 1 through 4.
Section 90.3 is clear that chapter 5 could modify the requirements in chapters 1 through 4. Often this is the case in chapter 5 and in many instances, the modifications or supplements are more restrictive.
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