Supervised Wiring with Classic Alarms

Use supervision with Classic Alarms to detect cut and shorted wiring

This article is a guide for classic Alarms. Refer to this article if you have new Alarms. See New Alarms vs Classic Alarms if you are unsure which version of Alarms you have.

---

In an unsupervised circuit, a cut wire on a sensor wired normally open or a shorted wire on a sensor wired normally closed is not detected as an alarm trigger. Supervision enables the Verkada BP41 alarm panel to detect these events and trigger a notification or alarm.

---

Supervision types

The BP41 alarm panel supports 2 types of supervision:

• Single End of Line Resistor (EOLR) (1 resistor)

• Double EOLR (2 resistors)

These two types of supervision can be applied to sensors wired normally open (NO) or normally closed (NC). Reference resistance values for each type are shown below.

Single EOLR supervision (1000Ω resistors)

Resistance	Normally Closed (NC)	Normally Open (NO)
0 Ω	Shorted circuit; trouble condition	Shorted circuit or closed event; alarm activated
1000Ω	Normal state	Normal state
Infinite Ω	Cut wire or open event; alarm activated	Cut wire; trouble condition

Double EOLR supervision

Resistance	Normally Closed (NC)	Normally Open (NO)
0 Ω	Shorted circuit; trouble condition	Shorted circuit; trouble condition
1000Ω	Normal state	Closed event; alarm activated
2000Ω	Open event; alarm activated	Normal state
Infinite Ω	Cut wire; trouble condition	Cut wire; trouble condition

---

Wire EOLRs to your BP41 alarm panel

Resistors are installed at the end of the circuit, as close to the sensor as possible for single and double EOL resistors. Installing EOL resistors at the panel inhibits the purpose of supervision.

Single EOLR	Double EOLR