Wrong Wiring on Two Smoke Alarms Indouble Fatal FireRead the full-text online article and more details about "Wrong Wiring on Two Smoke Alarms Indouble Fatal Fire" - Daily Mail (London), December 17, 2008Daily Mail (London)
Take a look at case #1, the easiest to understand. Note that again for simplicity the original Sears drawings did not show a grounding conductor that might be present in your wiring and that should always be present in modern electrical wiring. In Case #1, The lighting circuit feed wire...
A power-limited fire alarm circuit commonly referred to as PLFA, must have the voltage and power limited by a listed power supply that complies with NEC 760.121. Based on this section, a power source can be either (1) a listed PLFA or Class 3 transformer, (2) a listed PLFA or Class ...