A: The code has changed in recent years in terms of the way smoke alarms must be wired. In today’s electrical code it is required that each level of a home contain a smoke alarm.  When an event causes a single alarm to sound, all the smoke alarms in the home must sound. This has recently happened in my home. A friend left something on the burner to cook and came upstairs to chat. About ten minutes went by and all of a sudden the alarm went off next to where we were visiting. I had no idea what caused the alarm but followed the friend downstairs to discover 10″ of smoke on the ceiling. I was grateful my alarms were tied together.  I always recommend having at least one battery alarm as well and to place the alarms near cooking areas and in hall ways outside bedrooms. Remember you can never have too many smoke alarms. Be safe!