While I don't have any experience with the new BXP88, I do have a lot of experience with the BDL168's.
You can have 4 power circuits through a BDL168. In fact, that's how I wired up the ones at my club. Just remember that for 4 power groups you must break the sections down into the following: 1-4, 5-8, 9-12 and 13-16. You cannot wire across the sections, as in having section 3 and section 15 in the same power group. You can certainly wire up the sections together, but they must always be in groups of 4. For example, you can wire sections 1-4 and 9-13 to the same power group, then wire 5-8 and 13-16 to different power groups.
BTW, that power group can come from one booster or several boosters. It shouldn't matter at all, AFAIK.
That being said, I would keep the wire runs as short as possible. We have an issue at our large (currently 50' x 60') HO layout where the blocks farthest from the BDL's are always on. Basically, when the length of the conductor (wire + track) exceeds 50', the detector will be on. Period. And it is not adjustable.
This is why my club is replacing all the BDL's (eventually) with BOD's from RR-Cirkits. http://www.rr-cirkits.com/description/index.html These run the bus wires through toroid coils, which detect amperage. The BDL's detect resistance. It means that the BOD blocks can be any length at all; with no current there's no detection. With the BDL's, too much wire connected through an open circuit will set it off. I highly recommend the RR-CirKits for detection.
BTW, the RR-CirKits dectectors will talk to the LocoNet and JMRI.
The BD88 is basically a combined PM44 and BDL168, so not only do you get detection for each section, you get a breaker. Much easier to wire. The downside of course is that each one is only 8 sections compared to 16 for a BDL168. The easier wiring may win out over any cost difference though. Plus the BD88 has Transponding, although if you use mostly non-Digitrax decoders it probbaly won't work very well. Only a few non-Digitrax decoders work with Transponding (they don't transpond, they just don't interfere with decoders that do).
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
im trying to decide which block detector i should purchase for my layout in progress. im noticing Digitrax has sevral and im not sure why other than the obvious difrences (number of detection zones).
i have a double loop HO scale layout roughly 10'x14' with some passing sidings on the inner loop and a yard on the outer loop. im thinking keeping each loop and the yard its own power district with 6-8 detection zones per district. i would like to know if its possible or ok to have say 3-4 power districts all through one BDL168? or if it would be better for each power district to have its own BDL168 or BXP88?
also, im planning on having just one booster, not sure but i dont think ill need much more than that for the size layout im building.
i appreciate all your help,
ryan