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Electronic Theatre Controls Inc

Panic Wire Length in Echo Relay Panel (ERP) Mains Feed

Question

What is the maximum wire length and quantity of the devices listed below that can be used on Panic Wire 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 (sometimes slightly higher) drive on their Panic line. So it is a lot more susceptible to voltage drop. If using 16AWG wire we could get about 1000’ of total wire length and be safe. As an example let's say it's 75’ to the junction box, then 2 legs of 100’, which totals 275’ of cable length. BUT, the total wire length would be twice that at 550’. This is because the calculation for panic wire length must include both conductors within the same jacket, or both wires if run separately. Panic voltage probably shouldn't drop much under 3vdc.

  1. Use 16 AWG and keep total wire length under 1000'
  2. If you need longer kick up the gauge to 14 or 12
  3. Measure voltage at far end and make sure its above 3vdc
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Although it might be OK to mix the devices listed above since their voltage is similar, generally ETC recommends against doing so, and keeping like devices on a single Panic line. Devices which have differing voltages MUST be on separate outputs of the EBDK.