Читать книгу Maintaining Mission Critical Systems in a 24/7 Environment - Peter M. Curtis - Страница 64

One of the first steps in accomplishing the paradigm shift to DC is developing some consensus as to what DC voltage level is best for distribution, given the need to keep current levels and conductor ampacity within reason. The schools of thought range from 48 to 550VDC. These voltage levels that are under consideration fall under the National Electrical Code, ANSI/NFPA 70, which defines low voltage as any voltage up to 600 V. The grounding of DC systems is also covered in the NEC in section 250‐3 and 250‐22. Once the preferred voltage level is established, more specific codes and standards will have to be developed. Codes and Standards development is in progress overseas. The European Standard ETSI EN 300 132‐3 v 1.2.1 (2003‐08) covers DC systems up to 400V.