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NEC standard for Nipple

NEC standard for Nipple

NEC standard for Nipple


I'm a Mechanical Engineer working for the design of an offshore oil & gas platform by the company in South Korea. Since I'm not familiar with the NEC standard, I need help with my problem.

My PKG equipment skid has an explosion-proof instrument and cable is connected via a run of conduit (Reducer - Union - Nipple). Reducer and Union are Crouse-Hind products with UL certificate but Nipple does not have an Ex certificate. I asked C-H Korea if the nipple has an Ex certificate but they said the nipple does not require an Ex certificate for this application as per NEC standard. The project requires to apply NEC 500 / 505 for explosion-proof design and equipment is located on Class I, Zone2 (Div1, Zone2) area. Where can I find a reference that the nipple does not require an Ex certificate when it is used for the Zone2 area?

RE: NEC standard for Nipple

This may help you to drill down.
In the Canadian code the information is implied ih
Section: Hazardous locations.
Sub Section: Zone 1
Sub Section: Installations in Zone 1;
18-102 Wiring methods, Zone 1 (see Appendix B)
(1) The wiring method shall be threaded rigid metal conduit or hazardous location cables with associated cable
glands suitable for the application.
And in the notes to rule 18-102:
The CSA Standard for rigid metal conduit and couplings is CSA C22.2 No. 45.1. This Standard does not require
the markings for the conduit and couplings to indicate specific approval for hazardous locations. Certified rigid
metal conduit and couplings are suitable for hazardous locations without specific area classification marking.
Good question.
Good luck.

"Why not the best?"
Jimmy Carter

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