Closed Transition AIC Rating
Closed Transition AIC Rating
(OP)
I recall several NEC code cycles ago, there was a proposal made to add an clarification/exception to Section 110.9 or 110.10 where short periods of closed transition (maybe 20 ms) would not be required to be included in the short circuit calculations and the resulting withstand or AIC selections of the equipment.
I cannot locate this information or the final reply from the code making panel.
The proposal was knocked down, but I'm trying to find the actual wording from the CMP.
NFPA does not have all of the ROP/ROC's on the website. Does anyone else recall this?
What is your position when performing a study?
I cannot locate this information or the final reply from the code making panel.
The proposal was knocked down, but I'm trying to find the actual wording from the CMP.
NFPA does not have all of the ROP/ROC's on the website. Does anyone else recall this?
What is your position when performing a study?






RE: Closed Transition AIC Rating
When doing a study, I consider it an NEC violation (assuming the fault duty exceeds the breaker rating, which not always the case) and note in the report.
RE: Closed Transition AIC Rating
Go to this page:
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Click on "Proposals: Annual 2010 (2011 Edition) Proposals Before Panel Action" near the bottom of the page and when that opens scroll down to the Article 110 ROP for the 2002 code. I think the proposal you are looking for is 1-211.
Note to all: You can find all of the ROPs and ROC for teh 2002 through the 2008 code on this page as well as the propsals, without panel action, for the 2011 code.
RE: Closed Transition AIC Rating
Plus I am not aware of a setup that will perform a closed transition transfer in 20 ms.
RE: Closed Transition AIC Rating
(i.e. A closed transition transfer switch where the normal and alternate system is only paralleled a few cycles to insure sync then transfers)
JIM
RE: Closed Transition AIC Rating
Thanks. It was the references to the 1998 proposal that I was thinking of, but the one you sent completely covers it as it seems to be the original writer.
RE: Closed Transition AIC Rating
The submitter of the one that I linked to is a moderator on the Mike Holt forum and this topic came up over there too. He has posted a comment on this issue at
http://forums.mikeholt.com/showthread.php?t=110459
RE: Closed Transition AIC Rating