517.30(C)(3) and Seismic Design Category
- Thread starter roger
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- Logan, Utah
Roger,
In Utah, which is mostly a seismic design category D2, I have never seen anyone prohibit a HCF grade AC cable or 6 foot FMC whip with an insulated copper EGC from being used as a fixture whip for the essential system.
Chris
In Utah, which is mostly a seismic design category D2, I have never seen anyone prohibit a HCF grade AC cable or 6 foot FMC whip with an insulated copper EGC from being used as a fixture whip for the essential system.
Chris
Roger,
What has been your experience with this and inspections? Are you typically allowed to run whips to light fixtures? I have always thought it came down to the one word "necessary". The idea of 517.30 in my opinion is to ultimately protect the circuit, but if seismic design conditions come into play that may be an issue. How would seismic design go against the NEC?
Chris and LIM, until recently HFC, AC, or FMC whips have been the norm here and was never a problem, now I hear DHSR (NC's Healthcare AHJ) seems to apply the wording as it is written and require non flexible wiring methods to lay in fixtures in grid ceilings.
In this case as far as NC is concerned, most if not all of counties are in Design Category C and lay in fixtures are prohibited form being hard piped which does in fact bring 517.30(C)(3)(3)(4) into play, I just haven't had to bring it up yet.
I was just wondering if other areas AHJ's required hard pipe to fixtures in grid ceilings for Critical or Life Safety Branches.
Roger
In this case as far as NC is concerned, most if not all of counties are in Design Category C and lay in fixtures are prohibited form being hard piped which does in fact bring 517.30(C)(3)(3)(4) into play, I just haven't had to bring it up yet.
I was just wondering if other areas AHJ's required hard pipe to fixtures in grid ceilings for Critical or Life Safety Branches.
Roger
Ok, I am from NC also. What code do I find the prohibition for Design Category C and hard pipe. This could be a useful tool.
Ok, I am from NC also. What code do I find the prohibition for Design Category C and hard pipe. This could be a useful tool.
Here you go, the first link is to a CISCA Handbook which covers the codes and the second is where you will find the Seismic Design Categories, page 4 of the PDF (page 22 0f the document)
http://www.soundconceptscan.com/docs/Seismic_0-2_Guidelines.pdf
http://ecodes.biz/ecodes_support/free_resources/2012NorthCarolina/Residential/Part_I_Residential/PDFs/03_NC_Res_2012.pdf
Note that the handbook uses the term "rigid conduit" but that is not referring to RMC, it is referring to a "rigid" pipe or tubing. The key is that all grid ceilings are supposed to move in a seismic event, notice they are called islands and should not be rigidly attached to the structure. The Grid is supposed to float on the "L" molding that is attached to the wall
Roger
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