QUOTE (dwb @ 25 Oct 2008, 17:52)
<{POST_SNAPBACK}>There are two reasons for wiring the frogs separately
1) You are no longer relying on either the pressure of the switch blade or the little wiper underneath it to provide the power to the frog. This make running through the point more reliable in the longer term.
2) Once you stop using the switch blades to carry the power, they can be isolated from the frog and permanently bonded to their neighbouring running rail. This means you remove the risk of shorts caused by metal wheels passing through the gap between the switch blade and the fixed running rail. Even momentary shorts on DCC are a "bad thing" because they will shut the system down. On DC a momentary short will go un-noticed.
It is not a good idea to power the frog via a switch on the motor and retain power routing through the switch blades. You cannot guarantee that both power routes will switch at the same time, so you are quite likely to get shorts each time you change the points which is not what you want on DCC.
David
Thanks David - it all becomes clear why I was having such unreliable running through points!
I'm a bit of a novice - as I'm running DC should I be concerned with isolating the switch blades? If so, how do I do it?