That’s the number of TNT blocks required to (effectively) lock up my Minecraft client and cause issues connecting to the server. 64 didn’t do it and neither did 128 so I tried 196 – that did it.
Oddly enough, my son was not too far away and he wasn’t impacted at all. I’m guessing he was in another chunk (section of the map) that wasn’t impacted by one of the 196 blown up areas.
I think next time I’ll create a longer fuse and not connect it to the leader TNT until I’m pretty sure the redstone dust is inactive.
I ended up doing away with that map and starting another one.