ROP for selective coordination to 0.1 sec

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elec_eng

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I am trying to find old ROP/ROC that proposed to change the selective coordination to 0.1 sec instead of 0.01sec (or total coordination) but got rejected by the committee.

I remember it was discussed in the forum before I could not find that. Anyone has link to old ROP/ROC or old thread that has the link to this ROP/ROC?
 
Here is what is posted on NFPA's website in the ROC for the 2014 NEC in regards to 517.31(G) (2017 numbering)

15-58 Log #438 NEC-P15 Final Action: Accept in Principle
(517.30(F))
________________________________________________________________
Submitter: Neil F. LaBrake, Jr., National Grid USA
Comment on Proposal No: 15-66
Recommendation: Accept in principle in part to eliminate Exception 2 and
delete the term “selective” from “selective coordination” in the title and delete
the word “selectively” from “selectively coordinated” in the first sentence of
the proposed new section. This proposal should read in legislative text as:
(F) Selective Coordination. Overcurrent protective devices serving the
essential electrical system shall be selectively coordinated for the period of
time that a fault’s duration extends beyond 0.1 second.
Exception No. 1: Between transformer primary and secondary overcurrent
protective devices, where only one overcurrent protective device or set of
overcurrent protective devices exists on the transformer secondary.
Exception No. 2: Isolated power systems inherently comply with this selective
coordination requirement.
Exception No. 23: Between overcurrent protective devices of the same size
(ampere rating) in series.
Substantiation: This comment is the work of the Task Group on 2014
NEC/2012 NFPA 99 Correlation with the following representation: Larry Todd,
CMP-15; Don Talka, CMP-15; Jim Duncan, CMP-15; Sam Friedman, CMP-
15; Walt Vernon, NFPA 99; Dave Dagenais, NFPA 99; James Costley, NFPA
99; Chad Beebe, NFPA 99; Jim Dollard, NEC Correlating Committee; and Neil
LaBrake, Jr., NEC Correlating Committee (Chair). As directed by Mr. Michael
J. Johnston, NEC Correlating Committee Chair on June 8th, 2012, the Task
Group acted on correlation matters and conformance with the Standard Council
direction on “Installation vs. Performance” to resolve any conflicts or
inconsistencies resulting from proposed revisions in the A2013NEC Report on
Proposals (ROP) related to the 2012 NFPA 99. However, this Task Group did
not make a determination on any proposal with respect to “installation vs.
performance” except on Proposal 15-66 regarding the Standards Council
direction on the term “selective coordination”.
Exception 2 does not appear in NFPA 99-2012. The term “selective
coordination” is a defined term in Article 100 and used in several articles in the
NEC. This term is under the NEC Committee’s purview. Also, the term
“selectively coordinated” needs to be changed under this same concern. The
NFPA 99 term used in performance requirements of protective coordination
needs to be changed to remove any conflict with the NEC defined term
“Coordination (Selective)”.
Panel Meeting Action: Accept in Principle
Revise the text to read as follows:
(F) Selective Coordination. Overcurrent protective devices serving the
essential electrical system shall be selectively coordinated for the period of
time that a fault’s duration extends beyond 0.1 second.
Exception No. 1: Between transformer primary and secondary overcurrent
protective devices, where only one overcurrent protective device or set of
overcurrent protective devices exists on the transformer secondary.
Exception No. 2: Isolated power systems inherently comply with this selective
coordination requirement.
Exception No. 23: Between overcurrent protective devices of the same size
(ampere rating) in series.
Informational Note: The terms “Coordination” and “Coordinated” as used in
this section do not cover the full range of overcurrent conditions.
Panel Statement: The word “selectively” is removed in the first sentence to
make the wording of the section consistent with the removal of the word
“selective”. An informational note was added to clarify the meaning of the
terms “Coordination” and “Coordinated”.
Number Eligible to Vote: 14
Ballot Results: Affirmative: 13 Negative: 1
Explanation of Negative:
KRUPA, G.: While I agree-in-principle, I have serious reservations about the
changed definition of “Selective Coordination” made by a different committee;
this change has serious implications, especially for design engineers trying to
balance competing requirements of Art 517 with NFPA 99.
Comment on Affirmative:
SAMPSON, M.: Claiming jurisdiction of overcurrent coordination as a
design issue, the ELS committee of NFPA 99 is systematically diminishing the
effectiveness of the essential electrical system by limiting the coordination to
overload conditions only.
The ELS committee would have us believe that fully coordinated distribution
systems - where continuity of power is critical - are effective for elevators, fire
pumps and critical operation power systems, but oddly, will not work in a
hospital.
A properly designed selectively coordinated overcurrent protection
arrangement that localizes any overcurrent condition - short circuits and
overloads - to the conductors or equipment in which the overload or fault
condition occurs is a critical safety element that will be lost by this provision.
Click to expand...

I sat in on some of the discussion in regards to this issue at the NEC meeting. It was the health care facility engineers that pushed for the .1 second limitation to corridination.

Chris
 
raider1 said:
Here is what is posted on NFPA's website in the ROC for the 2014 NEC in regards to 517.31(G) (2017 numbering)

I sat in on some of the discussion in regards to this issue at the NEC meeting. It was the health care facility engineers that pushed for the .1 second limitation to corridination.

Chris
Click to expand...

Chris,

Thanks for the excerpt but I am actually looking for the 0.01 sec (total) requirement for 700 load. I believe there have been several tries to change that to 0.1 sec but got rejected. I need that ROP/ROC. I should have been clearer on my question.

I am reviewing a coordination study for a project where has several 700 and 701 loads and the engineer did not provide a total coordination (down to 0.01 sec). He only provided the coordination down to 0.1 sec. I ask him to provide total coordination per 700 and he disagreed with me and said the selective coordination doesn't mean a total coordination (0.01sec). I pointed out the definition of "Selective coordination" in art 100 but he insisted that the code did not say the selective coordination is required down to 0.01 sec.

I am trying to show him that's not what the NEC committee's intention.
 
There is no specific requirement for 0.01 second in 700.32.

As you mentioned the Definition of Selective coordination;
Coordination, Selective (Selective Coordination). Localization
of an overcurrent condition to restrict outages to the circuit or
equipment affected, accomplished by the selection and installation
of overcurrent protective devices and their ratings or
settings for the full range of available overcurrents, from overload
to the maximum available fault current, and for the full
range of overcurrent protective device opening times associated
with those overcurrents.
Click to expand...

Indicates that it should include the "Full range of overcurrent protective device opening times associated with those overcurrent."

Most trip curve data goes down to the 0.01 time frame so that would fall within the full range.

I was on CMP 10 at the time this was put into the code so I was part of the discussion when we changed the definition to include this language and it was intended to cover the lowest time on the time current curve.

Chris
 
Here is the Panel Statement we made for rejecting the 0.1 argument.

Panel Statement: The wording “accept in principle” accepted by CMP 10
during ROP meeting, clearly does not contain a requirement for when or where
selective coordination is required. It does however clarify the definition of
“Coordination, Selective”.
The NEC needs to remain the quintessential document for the electrical system
safety issue, and while the existing definition has served us well for many
years, it is now necessary to clarify the definition, not change the meaning. The
proposed changes add the specific clarity that is needed.
The wording accepted by CMP 10 is necessary to distinguish between the word
“Coordination” and the phrase “Selective Coordination”. The word
“Coordination” is often used to describe the isolation of downstream
overcurrent conditions over limited ranges of time and currents, but selective
coordination is used to describe the isolation of downstream overcurrent
conditions over the complete range of available overcurrents and the times
associated with those overcurrents.
The 0.1 second limit for isolation of downstream overcurrent conditions,
referred to in the substantiation of the submitter, actually describes
“Coordination” down to 0.1 seconds, not “Selective Coordination” down to 0.1
seconds.
The submitter is correct in that some Code Making Panels have agreed that
they need “total” coordination for certain life-safety related loads, and it is for
these life-safety related loads that they have chosen to use the phrase “selective
coordination” or “selectively coordinate”, rather than simply the word
“coordination” or “coordinate”. See NEC 620.62, 700.27, 701.27, and 708.54.
“Total Coordination” is synonymous with the phrase “Selective Coordination”.
The words “coordinate” or “coordination” alone are simply not sufficiently
specific enough to describe the concept as utilized by CMPs 12, 13, and 20.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12
Click to expand...

Chris
 
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