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CPI2 wiring question

A

andrewtac

Well Known Member
I am planning on purchasing a CPI-2 kit for my RV-8 soon. It has an IO-360 with slick mags, about 400 hours TT. I plan on a dual board with two coil packs. I am going to pull the panel apart for some lighting upgrades in a month or so and I want to prepare for the CPI-2 install at the same time. Looking at the install instructions I will need 4 power sources with circuit breakers and also switches for these sources. I was thinking about using 4 SPST circuit break switches (https://www.aircraftspruce.com/catalog/elpages/pbcircuitbrkr2.php?clickkey=4681) two at 15 amp for the red wires and two at 5 amp for the purple wires. I am running out of panel space and trying to minimize what goes in the panel. Would this set me up for install as far as power goes (no more circuit breakers or switches required).
 
The switchable breakers would work.

Alternative is you could use two DPST switches, one for each CPi2 board.

One switch controlling Red and Purple power wires to "A" or Primary cpi2 board.

Second switch controlling Red and Purple power wires to "B" or Backup cpi2 board.

You could label the switches IGN1 and IGN2 or IGN L and IGN R.

Having dedicated switches for the cpi2 insures proper shut down and timeout when powering down because these switches will break the cpi2 power wires from other electrical devices on you planes power bus(es).

Your switchable breakers might be more awkward for shutdown and turn on but they would do the job also.
 
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Then two switches and four breakers. I think DPST. Trying to minimize new additions to the panel. I agree 4 breaker switches would be awkward. Haven't committed yet, still thinking about what to do.
 
andrewtac said:
Then two switches and four breakers. I think DPST. Trying to minimize new additions to the panel. I agree 4 breaker switches would be awkward. Haven't committed yet, still thinking about what to do.
Click to expand...

Yes, I just finalized my panel layout with Steinair and that's what we did. 2-15a and 2-5a breakers and 2 switches for a dual CPI-2 system.

If I understand correctly, the switches are just there to completely isolate the CPI-2 units from the main bus in case there is any "back feed" from any of the other devices on the main power bus when the battery switch is turned off.
 
We found that some electronics leak tiny amount current onto the bus and this was sometimes enough to keep the CPI from shutting down.
 
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