Interconnecting Smoke Alarms using Powerline Carrier
 

Most building Codes now require the installation of Smoke Alarms in single family as well as multiple family residences. In fact many municipalities mandate 120VAC Alarms with battery back up, that are interconnected, especially for multiple family residences such as apartment houses, condominiums, etc. This means that when one of the interconnected Smoke Alarms senses smoke or fire, they all will sound the alarm. This is to satisfy the Audibility Requirement Statistics show that this arrangement saves people from being killed in case of fire.
 

Virtually all Codes have an Audibility Requirement for the smoke alarms. This is to insure that the occupants hear the alarm. This is true in multiple family residences such as apartment, condos, etc., where the noise from TVs, radios, air conditioners, and other appliances, can be substantial. The best way to insure the audibility requirement, in light of the background noise that can exist in multiple family housing, is with Interconnected Multi Station Smoke Alarms.
 

Therefore Codes usually require that the alarms be interconnected so that if one is triggered, they all sound the alarm. This interconnection is usually done by an additional (third) wire between the units.

The need for interconnected Smoke Alarms to satisfy the Audibility Requirements is greatly diminished when the 120VAC power is out. Since when the power goes, so go the attendant background noises caused by TVs, radios, air conditioners, and other appliances.

When it becomes necessary to interconnect smoke detectors, adding the third wire between the units is not always an easy thing to do, and can be prohibitively expensive.
 

The Model TR-SAI, Smoke Alarm Interconnect Module allows you to interconnect 120VAC, multi-station Smoke Alarms without adding a third wire between them. They communicate with each other through the Interconnect module via Powerline Carrier .
 

This means that when the 120 VAC power is out, the Smoke Alarms are no longer interconnected, and each Smoke Alarm functions as a Single Station Smoke Alarm, i.e., each Smoke Alarm activates independently as it senses smoke or fire. As was pointed out, the need for interconnected Smoke Alarms is greatly reduced if the 120 VAC power is out.
 

Interconnected Smoke Alarms are required to satisfy the Audibility Requirement of the Code, therefore this requirement is greatly reduced when the 120 VAC power is out. For this reason, Cepco Products Powerline Carrier is approved for Smoke Alarm Interconnection (UL 217).

Article by,

Paul Belcher
Cepco Products  (818) 998-8569
http://www.cepcoproducts.com
pbelcher@cepcoproducts.com