Save money on intrinsically safe installations. How? Here are three ways:

  1. Use a general enclosure with intrinsically safe apparatus; permitted by 504.10(B).
  2. Rather than use special wiring methods, use any of the wiring methods suitable for unclassified locations when installing intrinsically safe apparatus [504.20].
  3. Don’t seal enclosures that contain only intrinsically safe apparatus (except as required by 501.15(F)(3)); permitted by [504.70].
Where you can't save money:
  1. You must separate intrinsically safe conductors from nonintrinsically safe conductors [504.30(A)]. About half of Art. 504 is devoted to covering the details of how to do this.
  2. You must connect intrinsically safe apparatus, enclosures, and raceways (if metallic) to the equipment grounding conductor [504.50].
  3. Bond all metallic objects of an intrinsically safe system, per 250.100 [504.60].
  4. Ensure all intrinsically safe circuits are identified at terminal and junction locations in a manner that prevents unintentional interference with the circuits during testing and servicing [504.80].