conduit vs romex

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Back from taking my wife out to diner.
I tried to access reports on the NFPA web site, but it seems my membership has lapsed. I will have to fix this problem before I can search for the report.
 
I have heard that Chicago, that does not allow NM, has a reduced amount of electrical fires.
But only heard and no evidence of this.
 
Call me a skeptic, but I highly doubt that 10% of fires are caused by premises wiring.
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The AFCI people used statistics that show ~40% of dwelling unit fires originated in the building wiring system....not that I have ever believed anything the AFCI people have said.
Don
 
Tom,
I have heard that Chicago, that does not allow NM, has a reduced amount of electrical fires.
But only heard and no evidence of this.
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A former chief electrical inspector from Chicago submitted a comment on 210.12 that said:
2-132 Log #1741 NEC-P02 Final Action: Accept in Principle
(210.12(B) Exception)
_____________________________________________________________
Submitter: Timothy Arendt, Shamrock Electric Co.
Comment on Proposal No: 2-142
Recommendation: Replace the existing exception with the following revised
language.
Exception: AFCI protection shall not be required for that portion of the
branch circuit continuously enclosed in metal raceway with metal outlet and
junction boxes. Outlet-type or combination-type AFCI protection shall be
required for that portion of the branch circuit not enclosed in metal raceway.
Substantiation: The action of CMP 2 to require AFCIs on all dwelling unit
branch circuits is too broad and will lead to a move away from a ?without
amendments? use of the NEC. The term ?dwelling unit? includes not only one
and two family homes but also condominiums and apartments. Dwelling units
in condominiums and apartments - especially in hi-rises - usually have fire
resistive construction and more stringent wiring method requirements which
override the need for whatever benefit combination type AFCIs may provide.
My experience as past Chief Electrical Inspector for the City of Chicago
leads me to believe that an exception where metal raceway is used would be
appropriate and would provide an option that may make this requirement easier
for jurisdictions to accept.
In Chicago for the past 50 plus years 100% of legally constructed dwelling
type structures have used metal raceway and metal boxes as the wiring method
for the fixed wiring in dwellings. I have attached substantiation in the form of
NIFRS Data that compares Chicago vs National residential electrical fires. The
data shows that Chicago, which uses metal raceway exclusively for dwelling
occupancies, has (4) times fewer residential electrical fires as a percentage
of total residential fires, than found nationally. Moreover, there are nearly
(3) times fewer fires caused by the distribution, which includes the fixed or
installed wiring. The requirement for AFCI protection where NM Cable is used
will certainly lead to a reduction in fires. Unlike arc faults in combustible NM
cable, arc faults either series or parallel within non-combustible steel raceway
become enclosed short-circuits and ground faults. These short circuits and
ground faults are completely isolated from the fuel load and are handled very
well by conventional circuit breakers or fuses. The cost of requiring AFCI
protection to circuits already protected by non-combustible steel raceway is not warranted. In fact, my fear would be that the additional AFCI cost would
result in less use of metal raceway, which is a superior wiring method for
dwellings. All of the benefits of being able to add circuits or replace damaged
or aged conductors would be lost. The benefits of metal raceway in reducing
dwelling electrical fires was documented at the October 18-19, 2006 NFPRF
Symposium on Aging Electrical Wiring Systems.
This revised exception would also have the much desired effect of
encouraging device manufacturers to develop and reintroduce their outlet-type
AFCIs for protecting extensions to the fixed branch circuits. The combination
of metal raceway with outlet-type AFCIs should be an option for those desiring
this increased level of safety and protection.
Note: Supporting material is available for review at NFPA Headquarters.
Panel Meeting Action: Accept in Principle
Panel Statement: See panel statement on Comment 2-129.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 11 Negative: 1
Explanation of Negative:
BROWN, L.: Please see NAHB?s Ballot Comment on Comments 2-79 and
2-95.
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don_resqcapt19 said:
Tom,
A former chief electrical inspector from Chicago submitted a comment on 210.12 that said:
Click to expand...


Nice! I especially like the point about AFCIs driving up costs and making ECs cut corners in other areas.
 
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