Class 1 Div 2 Non Arcing, Sparking or Heat Producing

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lpfink

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Location
San Diego, CA, USA
(Using 2014- NEC)

I have been reading these forums for hours now and have come across many threads stating that an explosion proof box is not required or said another way that a general purpose box is acceptable for non arcing, sparking or heat producing components in a Class 1 Div 2 hazardous location. This includes terminal blocks and I'd imagine power distribution blocks too? So what about when it comes to the requirement of these non arcing, sparking or heat producing components themselves to be rated for a hazloc? What section of the NEC guides us on that? So I could put a general purpose enclosure with only UL listed (UL 1059 Terminal Blocks Standard) and other only listed parts in this enclosure as long as they aren't considered arcing, sparking or heat producing? And assume I'm wiring with MC-HL.

Also, how would one categorize their equipment to understand requirements using section 501- "III Equipment " when these sections seem to be pretty specific and I noticed they mostly about enclosures of the equipment. Why would there be no section for non arcing, sparking or heat producing with a few examples?

Thanks and I know it's a lot mixed up questions, shows my confusion!
 
rbalex

rbalex

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Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
Section 500.7 lists various protection techniques and where they are appropriate.

Basically, if a Division 1 or 2 protection technique is required, the text will say so; otherwise, a "general purpose" installation is acceptable.

There are some caveats:

  • The installation must still be suitable for the environment; for example, it may still need weather or corrosion protection.
  • Grounding/bonding still needs attention, even with general purpose wiring and equipment. [Section 501.30]
  • Section 500.8 also addresses some issues that may affect general purpose enclosures. Unfortunately, it must be gleaned from the text.
  • Intrinsically safe installations are wholly in the scope of Article 504. Articles 501 to 503 don't apply.
  • Section 90.1(A) always applies.

MC-HL is fine but usually unnecessary. It was primarily developed for Class I, Division 1.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
rbalex said:
Section 500.7 lists various protection techniques and where they are appropriate.
Section 500.8 also addresses some issues that may affect general purpose enclosures. Unfortunately, it must be gleaned from the text.
Click to expand...

Just out of curiousity what things have to be "gleaned"?
 
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