Question 9006 of 844 · Washington 01 Journey Level Electrician Exam
Zone 20, Zone 21, and Zone 22 classifications are used for which hazard?
Exactly one answer is correct.
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Correct answer to question 9006
- D: Combustible dusts and ignitible fibers or flyings
Explanation
Article 506 applies the zone system to combustible dust and ignitible fibers and flyings, using Zones 20, 21, and 22. Flammable gases and vapors use Zones 0, 1, and 2 under Article 505.
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