My HO railroad is powered by two MRC Tech 4 280’s (dual power packs). I also use a Tech 2 dual power pack for accessories that might overload my Tech 4’s.
My layout has lots of city street lights - station platform lights - light towers and structure illumination along with two dozen illuminated signal lights. I have blocked these circuits, operated by toggle switches, and all connected to the accessory terminals of the three power packs.
When they are all turned on - bad news - lights out. This happens after about 5 minutes or so of full accessory operation.
I have checked and rechecked for anything resembling a short - ain’t any to be found. Also have ensured that no particular block of accessories draws too much current for the lights connected.
Here’s the question: Is there a power device “out there” available for purchase that could be used just for the accessories?
I should add, some of my accessories (signal lights for example) operate on either AC or DC - so they have been put on a DC circuit. Still get the same results when all toggles are “on.”
Are all 3 power packs attached to all the accessories? Or does each operate a selected group of your accessories? If it is the first, you are probably getting a heat build up from the power units being connected to each other (not a good thing) causing them to cascade down as they fail. I assume that because you said, “…all connected to the accessory terminals of the three power packs”. Rewire your board so that only a select group of accesories is powered by an individual power pack, make sure that nonthing is wired so it can be powered by more than one pack, and you should be OK.
As for your question, I use a 16v DC pack made by Crest (AristoCraft) for all my accessories. Has more than enough to do the job, either 3 or 5 amps, I forget which. It sounds like you have a problem that could be a BIG problem (make sure your fire insurance is paid up). [:D]
I cannot imagine connecting three dual-pack power packs to the same accessories! So, yes - it is the latter. Certain accessories powered by certain accessory terminals. Power pack #1 - powers “ABC” lights; power pack #2 - powers “DEF” accessories, etc.