AFCI in Conduit (TREC SOP)

[Michael R. Boyett]

I would like to solicit opinions on one proposed Texas new SOP topic that I need interpretation help on. In the Electrical section, the proposed SOP states that the inspector is not required to “report the lack of arc-fault circuit interrupter protection when the circuits are in conduit;” (see pg1 of the attachment). After quizzing one of the Inspector Committee members on this he said that was supported by the 2008 NEC 210.12 exception rules 1 & 2 (see pg2 of the attachment). Well, I don’t read that rule nor exceptions that way and I would like your opinion. I read NEC 210.12 and the exceptions to say that AFCI is required even if conduit is used except in the case of a fire alarm branch circuit. It seems to me that the proposed SOP oversimplifies the rule & exceptions to the point of being in error. If not in error, then it will most certainly result in confusion for the inspector in the days to come. May I have your thoughts on this? If I’m wrong then so be it, if I’m right then I’d like to attempt to get that section clarified prior to it being adopted by TREC.

I’ve attached the proposed SOP wording (pg1) and a page from www.NECPlus.org (pg2) that describes the rule and exceptions in more detail.

afci-conduit.doc

[Greg Fretwell]

Conduit does not relieve the necessity of AFCI protection. The conduit rule only reflects the use of a device type AFCI and requires conduit on the line side of the AFCI.
Most of the exposure to arc is still on the customer side of the receptacle.

[Barry Adair]

Michael,

I've gone Desi, "'splain to me Lucy, how he justifies his interpretation"

I believe a thorough reading of this may change his mind and would be intrigued to see where in Texas this is or would apply in residential construction.
All of the steel framed houses I've inspected us NM cable...

2005 NEC—210.12
Arc-Fault Circuit-Interrupter Protection.
(B) Dwelling Unit Bedrooms. All 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets installed in dwelling unit bedrooms shall be protected by a listed arc-fault circuit interrupter, combination type installed to provide protection of the branch circuit.
Branch/feeder AFCIs shall be permitted to be used to meet the requirements of 210.12(B) until January 1, 2008.

FPN: For information on types of arc-fault circuit interrupters, see UL 1699-1999, Standard for Arc-Fault Circuit Interrupters.

Exception: The location of the arc-fault circuit interrupter shall be permitted to be at other than the origination of the branch circuit in compliance with (a) and (b):
(a) The arc-fault circuit interrupter installed within 1.8 m (6 ft) of the branch circuit overcurrent device as measured along the branch circuit conductors.
(b) The circuit conductors between the branch circuit overcurrent device and the arc-fault circuit interrupter shall be installed in a metal raceway or a cable with a metallic sheath.

2008 NEC—210.12
Arc-Fault Circuit-Interrupter Protection.
(B) Dwelling Units. All 120-volt, single phase, 15- and 20-ampere branch circuits supplying outlets installed in dwelling unit in family rooms, dining rooms, living rooms, parlors, libraries, dens, sun rooms, recreation rooms, closets, hallways, or similar rooms or areas shall be protected by a listed arc-fault circuit interrupter, combination type installed to provide protection of the branch circuit.

FPN: For information on types of arc-fault circuit interrupters, see UL 1699-1999, Standard for Arc-Fault Circuit Interrupters.

Exception No. 1: Where RMC. IMC, EMT or steel armored cable, Type AC, meeting the requirements of 250.118 using metal outlet and junction boxes is installed for the portion of the branch circuit between the branch circuit overcurrent device and the first outlet, it shall be permitted to install a combination AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.

The action in these proposals deleted the phrase “supplying outlets” and the word “bedrooms” now requiring AFCI protection for all 120-volt, single-phase, 15- and 20-ampere branch circuits in family rooms, dining rooms, living rooms, parlors, libraries, dens, sun rooms, recreation rooms, closets, hallways, or similar rooms or areas. In addition, the last sentence, permitting branch/feeder AFCI devices until January 1, 2008, has been deleted, and the effect is to now require only listed combination AFCI branch circuit protection.


A new exception has been added permitting RMC, IMC, EMT or steel AC cable to protect the branch circuit to the first outlet with the 6-foot length deleted.


The NEC is an ever-changing, ever-improving document, and these are only some of the most important changes for the 2008 version. For more information, see “Stallcup’s Illustrated Code Changes, 2008 edition”. EC
ODE is a staff engineering associate at Underwriters Laboratories Inc., in Research Triangle Park, N.C. He can be reached at 919.549.1726 or at mark.c.ode@us.ul.com. James G. STALLCUP is the CEO of Grayboy Inc., which develops and authors publications for the electrical industry and specializes in classroom training on the NEC and OSHA, as well as other standards. Contact him at 817.581.2206. James W. STALLCUP is vice president and senior editor at Grayboy.

[Mike Whitt]

Let’s take a quick look at a GFCI protected receptacle before looking at the metal raceway and AFCI.

A GFCI protected receptacle in a kitchen area can have the first receptacle be a GFCI device that protects all the other receptacles on that same circuit or a GFCI can be installed at each and every receptacle outlet.
Using these installations can be covered with one GFCI overcurrent device being installed in the panel.
Either of the three will protect persons using each of these receptacles.

Metal raceways and Arc-Fault;

Conductors installed in a metal raceway will have some protection from arcs due to the nature of the raceway. In other words should there be some sort of arcing taking place in a metal raceway then one of two things will happen. One the arc will fault to ground due to the bonding of the metal raceway and open the overcurrent device and second any fire involved would be contained in the metal raceway.

The exception will allow metal raceways to the first outlet where the AFCI would be installed to protect everything downstream just as the GFCI protects everything downstream.

I disagree with the proposal and would use the scenario as outlined above as my support.

[Barry Adair]

Originally Posted by Mike Whitt

Let’s take a quick look at a GFCI protected receptacle before looking at the metal raceway and AFCI.

A GFCI protected receptacle in a kitchen area can have the first receptacle be a GFCI device that protects all the other receptacles on that same circuit or a GFCI can be installed at each and every receptacle outlet.
Using these installations can be covered with one GFCI overcurrent device being installed in the panel.
Either of the three will protect persons using each of these receptacles.

Metal raceways and Arc-Fault;

Conductors installed in a metal raceway will have some protection from arcs due to the nature of the raceway. In other words should there be some sort of arcing taking place in a metal raceway then one of two things will happen. One the arc will fault to ground due to the bonding of the metal raceway and open the overcurrent device and second any fire involved would be contained in the metal raceway.

The exception will allow metal raceways to the first outlet where the AFCI would be installed to protect everything downstream just as the GFCI protects everything downstream.

I disagree with the proposal and would use the scenario as outlined above as my support.

This assumes the entire install is/was done correctly, very seldom seen on this planet, anyway.

[Greg Fretwell]

The only reason they added the device type AFCI is for panels that will not accept the breaker type (old models and fuses). You could still do it with a modern panel but the added expense and labor of the metal wiring method would be more than just buying the AFCI breaker ... assuming the device style is cheaper in the first place like the GFCI. I have never seen one.