Article 500 vs. 505

[tim janof]

Can somebody please explain what the general idea of Article 505 is? What does it do that Articles 500-504 don't? Is it less restrictive or something? Is it only to be used by certain industrial institutions? Thanks.

 

[dana1028]

Re: Article 500 vs. 505

somewhere Mike Holt gives a real good explanation - but ...in a nutshell...this section is for companies/corps that are multi-national....Europe uses the Zone system...so the NEC is recognizing this system in 505...for those corps who want just one system of identifying these classes/zones, they use Art. 505

 

[rbalex]

Re: Article 500 vs. 505

Originally posted by tim janof:
Can somebody please explain what the general idea of Article 505 is? What does it do that Articles 500-504 don't? Is it less restrictive or something? Is it only to be used by certain industrial institutions? Thanks.

Art 505 recognizes electrical area classification using a method similar - not identical - to the International Electrotechnical Commission (IEC) "Zone" system for Class I locations. Art 505 definitions for Zones are significantly different than the IEC's. Art 505 recognizes specific protection techniques suitable for locations classified by NEC Zones.

Art 505 does not cover Class II or III locations (Arts 502 & 503).

Locations that would be probably be classified as "Division 1" in Art 500 would be classified as either "Zone 0" or "Zone 1" in Art 505 depending on the length of time a location is likely to be hazardous. Zone 0 protection techniques are very restrictive - only intrinsically safe systems are permitted. Zone 1 protection techniques are generally less restrictive than Division 1.

Zone 2 and Division 2 are comparable in the Code .

Any institution may use either method; however, the systems are different enough that the Code currently requires a P.E. to make or supervise the creation of electrical area classification documents.