sda said:
So you'd leave the box open without a cover and the splices exposed?
Whatever.
So you'd feed the incoming cables directly into the box through a bare knockout hole?
Maybe you're visualizing it differently, but I see the smoke cables going into the box, spliced, and a single cable going into the Elk enclosure through the chase nipple. IVB is trying to eliminate clutter in the Elk enclosure. Going from 7 cables to 1 helps.
You really have zero idea of the install and how it's all going to be put together in this case. Trade vs. tinkering here.
Let me connect the dots and provide a compliant and clean install for you, as you don't get it based on the hardware and bill of material. Step by step if you will.
First, the OP states the cables come in via the top box in the closet or whatever is there.
1. Mount the 4" square over the existing mud ring. Actually, in this case, I'll amend my BOM to be 2 extension rings and no box, just to appease you with the lack of a bushed opening.
2. The 4" gets nippled to the M1 enclosure, preferably via a 3/4" offset.
3. Make up the daisy chain in the existing box and extended box (#5 4/18 would equal 4 junctions or 8 wire nuts in this case for that daisy) and I'd recommend crimping the EOLR to the last pair and not use nuts. I would put the RRS in the 4" square with the loop daisy chain in this case, junction as needed (ok, now we're up to 10 total wire nuts here, either blue or orange) Either way, TONS of space in both the recessed box in the wall and the 4" and extension for all the hardware here. Fold conductors into box as typical.
4. From the 4" the OP will need 9 conductors of FPL. 2 pieces of 18/4 and a single conductor stripped out.
5. The 2WMOD gets wired to the panel the same as a 4 wire smoke. Land cables on module as in directions.
6. The power for the reversing relay gets wired from where the OP chooses (usually the host panel) but NOT switched
7. The relay gets triggered via OUT3 and grabs a + trigger via a jumper off the panel AUX (this is only a signal and really doesn't draw anything off the panel for calcs).
8. The pair from the MOD for maintenance/freeze gets wired to any panel zone and programmed appropriately. Resistors for both panel IDC's get wired at the MOD.
9. Mount the module on the 4" and install it's provided faceplate. Zero exposed splices, uncovered junction or unbushed knockout.
End result is from 20 conductors entering into the panel, or enclosure there's now officially ZERO splices made in the panel and the wiring is actually quite simple. The fire loop now provides a maintenance signal to the panel (clean me) for the smokes and can also report a freeze trouble, provides a compliant tandem ring (temp-3) at ALL system smokes irregardless of the panel, allows the "smart walk test" feature to be used on the I3 smokes and furthermore, the fire loop appears as a 4 wire loop to the M1, negating ANY incompatibility that may be perceived as the reason to install 4 wire detectors in the first place.
I'm now counting 2 cables and a single trigger wire going through the nipple.
Also provides (if module swapped and smokes changed) a migration path to install I4 detectors on the same loop and provide CO on the same IDC with only the addition of another pair of signal wires from the box to the M1.
Furthermore, if the OP wanted to clean up the wiring further, I would run the panel AC wiring and any power wiring that is going to the second "level" out via a NM connector or knockout bushing (cat's ass) on the side of the 4" and call it a day.
Let me know if you don't understand any of the reasons, methodology, trade terms, or workmanship questions SDA.