Actually…Russell if you are speaking of the 2008 NEC in regards to 210.12, the it will read this as it stands right now.
**210.12 Arc-Fault Circuit-Interrupter Protection.
(A) Definition: Arc-Fault Circuit Interrupter (AFCI).
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 deenergize
the circuit when an arc fault is detected.
****(B) Dwelling Units. ****All 120-volt, single phase, 15- and
20-ampere branch circuits installed in dwelling units shall
be protected by a listed arc-fault circuit interrupter, combination
type installed to provide protection of the branch
circuit. [ROP 2–105, 2–142, 2–111]
FPN No. 1: For information on types of arc-fault circuit
interrupters, see UL 1699-1999,
Standard for Arc-Fault
FPN No. 2: See 11.6.3(5) of NFPA 72®-2007, National
Fire Alarm Code® for information related to secondary
power supply requirements for smoke alarms installed in
dwelling units. [ROP 2–118a]
FPN No. 3: See 760.41 and 760.121 for power supply
requirements for fire alarm systems.
*Exception: The location of the arc-fault circuit interrupter
shall be permitted to be at other than the origination of the
branch circuit where the arc-fault circuit interrupter is installed
within 1.8 m (6 ft) of the branch circuit overcurrent
device as measured along the branch circuit conductors.
**[ROP 2–147, 2–137]