The requirements with which electrical equipment has to comply to provide intrinsic safety in explosive atmospheres have been a matter of previous discussion. However, when such equipment has been installed, the question arises as to whether an intrinsically-safe circuit has in fact been ensured. There is no immediate answer to this, and the Author's purpose here is to describe problems that may arise when installing such equipment. The article is mainly arranged under the headings: (1) Problem of circulating currents resulting from circuit inductance. (2) Study of connections between appliances. (3) Installation of safety barriers. (4) Installation containing several barriers. (5) Choice of cables. (6) Electromagnetic coupling (between circuits). It is concluded that, in the design and installation of intrinsic-safety equipment for dangerous zones, the main precautions needed are: (i) the intrinsic-safety circuits should be earthed only when absolutely necessary; (ii) armoured cable should be used only when unavoidable; and (iii) intrinsic-safety equipment should be connected only to instruments that involve no possibility of earthing safety-circuits or of raising them to a dangerous potential. It may be considered that such precautions are unnecessary where the interconnecting earthing network is in perfect condition, but it should be remembered that such networks are expensive and require special attention to maintenance. It is also mentioned that tests suggest that the influence of the inductance of connecting cables in safety circuits in negligible. Order from: BSRA as No. 47,593.

  • Supplemental Notes:
    • This is a special English Issue.
  • Corporate Authors:

    Bureau Veritas

    One Western Union International Plaza
    New York, NY  United States  10004
  • Authors:
    • Cosse, D
  • Publication Date: 1977-10

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00170884
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Mar 14 1978 12:00AM