that's helpful. Thanks. And just as a clarification, when I said EOLR I meant end-of-line-relay, which i do indeed have configured for power supervision on each zone (i realize that's a confusing acronym, as sometimes the "R" is for resistor, but in this case, I meant relay. Each of the smokes is a GE 541NCXE, with a built in relay). Knock on wood, no problems so far after 4 years of operation, but I understand your warnings. Thanks again for explaining