Panic Wire Length in Foundry Mini Panel (UFMP)
Question
What is the maximum wire length and quantity of the devices listed below that can be used for an emergency contact input with an EBDK (Emergency Bypass Detection Kit)?
- Echo Relay Panel (ERP) Mains Feeds
- Echo Relay Panel Feedthrough (ERP-FT)
- Sensor IQ (SIQ)
- Echo Room Controller (ERMC)
- Foundry Mini Panel (UFMP)
Answer
These all have about 3.5VDC on their emergency contact line, making them susceptible to voltage drop. With 16AWG wire, an emergency contact line can have about 1000’ of total wire length. Note that for wire length calculations, you must use the length of both conductors used for the contact. If you had 275’ of cable length, the total wire length would be twice that at 550’. Emergency contact voltage may not be reliable under 3VDC.
- Use 16 AWG and keep total wire length under 1000'
- 12 or 14 AWG wire can be used to reduce voltage drop and increase the maximum wire length.
- If you have issues correctly triggering any emergency contacts, measure voltage at the far end and make sure it is 3VDC or greater.
UL924 requires that only devices of the same type may share an emergency contact line. Do not mix device types on a single EBDK output.
