AFCI Applications in Dwelling units

[stanxp]

There seems to be a lot of confusion on the 2008 Code interpretation regarding the application of AFCI's in single family dwellings.
Article 210.12(B) states all 15A and 20A branch circuits supplying outlets installed in dwelling units (list of rooms given) are to be protected by a listed AFCI combination type breaker.
Question: Does this articles apply (AFCI combination type protective device) to seperate lighting branch circuits and seperate smoke detector chain circuits for the rooms listed?

 

[charlie b]

The rule is stated in terms of outlets. A light fixture and a smoke detector are outlets. So yes, it would apply. Welcome to the forum.

 

[stanxp]

AFCI Applications

AFCI Applications

Thanks Charlie,,
Can you point me to where the code defines light fixtures and smoke detectors as "outlets" in a family dwelling unit

 

[charlie b]

Sure. Just take a look at the article 100 definition of the word, "outlet." A light fixture, for example, takes current from the premises wiring system, since its wires are connected to building wires inside the box to which the light fixture is mounted. A smoke detector does the same thing. Both therefore meet the definition of "outlet." This is true in any type of building, not just a dwelling unit.

 

[Cavie]

Thanks Charlie,,
Can you point me to where the code defines light fixtures and smoke detectors as "outlets" in a family dwelling unit

The term outlet is the same in commercial and residential. Look up deffinition of outlet. Outlet does not mean receptical.

 

[stanxp]

AFCI Applications in Dwelling Units

AFCI Applications in Dwelling Units

Here are a couple suggestions that might help eliminate the confusion and miss-interpretation of the changes made in the 2008 NEC regarding the definition of an ?outlet? as it pertains to the application of AFCI?s.

1. Drop this definition in its current form and simply address the type of OCPD to be applied in branch circuits that include specific types of loads and equipment in specific locations of a family dwelling unit.

2. The current definition of an ?outlet? in the 2008 NEC code is misleading and applies to any termination point in a series or parallel circuit where current is taken or supplied to utilization equipment. In electrical engineering terminology these intermediate locations are referred to as ?nodes? or ?node points?. OCPD?s are typically not understood to be protecting node points ? hence suggestion # 1 above.

3. AFCI?s have sensitive characteristics and are susceptible to nuisance trips. Although this may be a fail safe situation for certain safety conditions, it does not seem to be a logical application for potentially life saving systems such as smoke detectors in family dwelling units. It can be argued that AFCI?s in smoke detector branch circuits in family dwelling units is an unreliable condition coupled with the fact that battery back-up is strictly human factor dependent which again is not a reliable condition, evidenced by the thousands of dwelling fires where lives were lost only to discover the smoke detector circuit or back-up batteries were non-functioning.

4. Drop the requirement in article 760.41 which states AFCI?s shall be installed in dwelling smoke detector branch circuits as covered by the requirements of article 210. However, maintain the same OCPD requirements as for fire alarm systems that recognizes for the reasons stated in 3 above.

 

[Dennis Alwon]

Stan, IMO, there is no problem with the way it is written. I have never had an issue understanding this requirement.

 

[480sparky]

Here are a couple suggestions that might help eliminate the confusion and miss-interpretation of the changes made in the 2008 NEC regarding the definition of an ?outlet? as it pertains to the application of AFCI?s. ..........

If you feel strongly about this, submit a proposal for the 2014.

........1. Drop this definition in its current form and simply address the type of OCPD to be applied in branch circuits that include specific types of loads and equipment in specific locations of a family dwelling unit......

Now you're treading into design issues, which are outside the realm of the NFPA and NEC, which deal with safety.

.....2. The current definition of an ?outlet? in the 2008 NEC code is misleading...........

It's pretty simple to understand what an 'outlet' is. You're reading far too much into it.

3. AFCI?s have sensitive characteristics and are susceptible to nuisance trips. ..........

"Nuisance" trips are typically an arc fault detection. If not, then it's a ground fault, which an AFCI can detect and react to. The AFCI is simply doing what it is designed to do.

4. Drop the requirement in article 760.41 which states AFCI?s shall be installed in dwelling smoke detector branch circuits ..........

Smoke detectors are not covered by 760. 760 is for Fire Alarm Systems, resi smoke detectors are appliances.