National Electrical Code Top Ten Tips:
Article 513, Aircraft Hangers

1. Article 513 covers any structure used for storing or servicing aircraft containing Class I (flammable) or Class II (combustible) liquids whose temperatures are above their flashpoints [513.1].
    
2. Article 513 does not cover unfueled aircraft [513.1].
    
3. Article 513 provides four classifications of locations: Below floor level, Areas not cut off or ventilated, Vicinity of aircraft, and Areas suitably cut off and ventilated [513.3].
    
4. When installing equipment in a location that is in, may be in, or may be operated in, a Class I location, comply with the applicable provisions of Articles 501 and 505 [513.4(A)].
    
5. If the location isn't Class I but is a hanger, then you must install the wiring in metal raceways unless the area is "suitably cut off and ventilated." Alternatively, you can use Type MI, TC, or MC cable [513.7(A)].
    
6. If wiring runs under or in the hangar floor, it must comply with Class I, Division 1 requirements [513.8(A)].
    
7. You can't use standard cords for pendants. The flexible cord must be identified for hard usage or extra-hard usage. And it must have a separate equipment grounding conductor [513.7(B)]
    
8. If a receptacle is in an area where it might be used for electrical diagnostic equipment, electrical hand tools, or portable lighting equipment, it must be GFCI-protected [513.12].
    
9. 513.16(A) contains confusing language. The subtitle of 513 refers to grounding and bonding. What it means is bonding (see Article 100 definition). Nothing in this passage has anything to do with grounding. You accomplish nothing by grounding a raceway. What you want to do is bond it.
    
10. Maintain the continuity of the bonding conductor (which, in the NEC, is incorrectly referred to as the equipment grounding conductor or EGC in direct conflict with Article 100 definitions) [513.16(B)(1)].