Paul D
N scale Washita and Santa Fe RailroadSouthern Oklahoma circa late 70's
PEDUnless you have a lot of excess wire under your layout which can move around and make undesired contact somewhere, why cover the splices with anything other than for appearance? The bare wire is no different than all the track you have exposed topside.
Because when you forget and put something conductive under the layout (or someone else does) you dont run the risk of damaging your equipment with a dead short (it has been done).
Also typically I do not like taking electrical shocks when I reach under my layout. so I heat shrink all of my soldered connections. 14VAC still isnt good for you.
If you buy new DCC/sound locomotives in the $200-500 range, why skimp on the wiring?