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Cranes and Hoists, Part 1

Cranes and Hoists, Part 1Cranes and hoists are essential to modern industrial facilities and construction operations. Because they present their own set of potential hazards, the NEC devotes Article 610 to the requirements for installing the electrical equipment associated with them.

The first thing to note is there are special requirements for hazardous locations [610.3(A)]. Refer to Article 501, 502, or 503 as appropriate, plus Article 500.

So what if you’re not installing a crane or hoist in a Hazardous Location but it’s going to operate over combustible materials? In that case, you need to ensure the resistors are in a cabinet, cage, or cab composed of noncombustible material [610.3(B)]. If it’s an electrolytic line, you need to refer to 668.32.

Part II of Article 610 is pretty much the “meat” of the Article. It’s all about the wiring. Some things to note about conductors for cranes and hoists are that they have their own:

  • Ampacity table and correction factors [Table 610.14(A)].
  • Demand factors [Table 610.14(E)].
  • Secondary conductor rating factors [Table 610.14(B)].
  • Two other highlights of Part II:
  • Flexibility is factored in. There are requirements for flexible connections to motors [610.11(C)] and to moving parts [610.11(E)]. Any flexible cord or cable must be listed (and used with proper take-up devices or reels as necessary) [610.13(C)].
  • Conductors leaving raceways or cables must be routed through separately bushed holes [610.01(A)]. Or, in lieu of a box, through a bushing [610.12(B)].

Part 2 » | Source: Mark Lamendola | Mindconnection