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Smoke Detector & Arc Fault Circuit Interrupter Requirements & Frequently Asked Questions

For one- and two-family dwellings - consult the National Electric Code - 2002 Edition Current N.C. Amendments.

What is the function of a smoke detector?
A smoke detector/alarm is a device used to measure amounts of smoke and signa an audible sound announcing a potential hazardous condition.

When and where are smoke detectors required to be installed?

1. On the ceiling or wall outside of each separate sleeping area in the vicinity of bedrooms.
2. In each room used for sleeping purposes.
3. In each story within a dwelling unit, including basements and cellars but not including crawl spaces and uninhabitable attics.
4. The units shall be interconnected such that the activation of one alarm will activate all alarms.
5. When primary power is interrupted the smoke alarm shall receive power from a battery.
6. The smoke alarm shall be supplied by a single branch circuit serving one or more of the required lighting outlets and permanently connected ahead of the switching devices.

Where can I find more information about the requirements of smoke detectors?
Additional information can be found in the 2002 or current edition of the National Electrical Code Section 210.71.

What does "in existing areas" mean?
Where construction does not result in the removal of wall or ceiling finish (to expose the building structure). Otherwise a batter operated device shall be allowed to meet these requirements. This exception is to be applied only if the finish surface is not removed in the area where smoke alarms are required. An alarm is not required to be hardwired if wall or ceiling finishes are not removed. If the work is requiring a smoke alarm to be installed, openings in the wall or ceiling, the alarm must be hardwired and if not, the alarm may be battery operated.

Is a permit required to install smoke alarms?
Electrically operated (hardwired) smoke alarms require a $25.00 permit. Battery operated smoke alarms do not require a permit and the owner is responsible for maintaining compliance.

Additional Information
The smoke alarm must be approved and listed and shall be installed in accordance with manufacturer's instructions.

An Arc Fault Circuit Interrupter is:
A device intended to provide protection from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit when an arc fault is detected.

NEC 210.12(B)
All branch circuits that supply 125-volt, single-phase, 15- and 20- ampere outlets installed in dwelling unit bedrooms shall be protected by an arc-fault circuit interrupter listed to provide protection of the entire branch circuit.

Using microprocessor technology, the device senses fluctuations in electrical waves that indicate arcing or sparking along the conductors. The AFCI's will open a circuit inside walls that have been damaged by nails, screws, staples, and many other ways. It may take a year or even ten years before it becomes a fire. The new circuit breaker (microchip) senses the slow build-up of heat from the damaged conductor or loose connection and opens the circuit before it turns into a damaging fire.

General Questions about AFCI

Does a lighting outlet installed in a closet that has entry from a bedroom have to be protected?
Yes, see NEC 210.12b.

Must the smoke detector be AFCI protected?
Yes, NEC.

Are AFCI required in the following applications?

1. Room air conditioner plug connect Bedroom. Yes.
2. Burglar alarm system in basement plug connected. No, 210.8.a.5. exc. #3.
3. All bedroom outlets. Yes.
4. Smoke detectors installed in bedroom. Yes.