The end-of-line resistor is the cheapest part on the truck and the one that opens the most loops when it goes missing. Here is how to pick the right one.
Why the value is not universal
There is no single EOLR value that works everywhere. The correct value depends on the panel and the circuit type — Class A vs. Class B, conventional vs. addressable supervisory. Using the wrong value can leave a circuit in trouble or, worse, defeat supervision.
The values worth keeping on the truck
We stock the common values — 47K, 4.7K, 3.9K, and 10K — so you can match whatever your panel specifies instead of improvising. When you are replacing one, match the value marked on the resistor you are removing or the value called out in the panel documentation.
Don’t let a 10-cent part open a loop
A missing or wrong end-of-line resistor is one of the most common and most avoidable inspection findings — it shows up right alongside dead panel batteries on the typical punch list. See the most common fire alarm inspection failures for the full list, then browse our fire alarm parts and keep the full set of resistor values on hand.
