No, not as you are describing. ALL new wiring must meet new codes, even extensions, proper equipment grounds, and grounding type receptacles.

NEC 382.10 & 382.12

http://freenec.com/T200.html

NEC 250.130 (C)

http://freenec.com/T94.html

NEC 406.3 (D)

http://freenec.com/T235.html

NEC 250.118

http://freenec.com/T91.html

NEC 250.2

http://freenec.com/T72.html

NEC 250.122

http://freenec.com/T93.html

Do you have some parts of the house that have NM-B (with a ground) running all the way back to the breaker box? If you can properly ground the smoke detector's NM-B at the junction I believe it would be acceptable. You could run a separate ground wire back to the breaker box or to the nearest receptacle or junction box that is properly grounded.

Bruce

"You could run a separate ground wire back to the breaker box or to the nearest receptacle or junction box that is properly grounded."

Then you would just run new nm-b from the panel or extend from the properly grounded circuit with nm-b for the smoke detectors... one would think... why would you want to make it difficult by involving two circuits for something as simple and benign as smoke detectors?

To begin from the start of the circuit. Main breaker panel 14-2 NMB with ground on a 15 amp 120 volt circuit breaker to the 1st smoke detector each additional smoke detector will be fed by 14-3 NMB with ground (jumper wire) for a total of 10 openings. Using the 14-3 NMB with ground links all the smoke detectors into a chain if one goes off they all go off. With most name brand smoke detectors on today's market the offending smoke detector that tripped and make the alarm sound will be flashing red instead of a solid green indicator light. www.dbelectric.us

By having a dedicated circuit breaker or breakers for the smoke detectors allows you to turn the circuit off when a needless oven broil smokes the house up Just remember to turn it back on when the smoke clears. And look for 120 volt smoke detectors with 9 volt dc battery backup in case all power is lost.