Dead frog points:

While I always recommend live frog pointwork, sometimes you have no option but to use dead frogs (if you are using peco setrack or hornby for example) In which case, I recommend using insulated joiners as for live frog points. While normally you would not do this (they are supposedly simpler to wire) you can sometimes get problems occurring when a metal wheel bridges the insulated gap at the crossing. This causes a short circuit as both rails are powered due to ‘back feeding.’ Using insulated joiners will remedy this as shown. You might lay dead frog points without insulated joiners and never get a problem, but it’s far better to take a thorough approach than have to alter things later on if problems arise. Remember though; this is not a DCC-only technique, and is equally applicable to DC layouts in places where the point is powered from both ends (for example, where a siding branches off from a main line)