Smoke detectors on AFB protected circuit

[Ernie Simpson]

Did a new construction today. The smoke and CO detectors were wired on an arc fault protected circuit. This can't be right, can it?

[Rick Cantrell]

Did a new construction today. The smoke and CO detectors were wired on an arc fault protected circuit. This can't be right, can it?
Yes, it is correct.
Newer codes require outlets to be arc fault protected, even smoke detectors.
Think of this
When there is an arc fault on that circuit the arc fault will trip. Since the arc fault tripped, there is no power to the circuit and therefore less chance of a fire. But since the smoke detector has battery backup the smoke detector still works.
This is a nearly perfect plan.

[Jim Port]

It is required by the NEC since shortly after 2000.