SC-1 - switch power question

I KNOW ONE THING....make sure it is right. The sc-1 will fry....The sc-1 alleviated the cooking issue on wrong hookup.

You want to power you switches separately from the track for several reasons.  First the older lionel switch machines have a 'sweet spot' right around 14 volts where the operate the best, so you can set an accessory transformer there and leave it set.  which ties into number two, at lower voltages the switches do not throw very well, so if you have a slow moving train, chances are good your switches will not fully throw, and the anti-detailing feature will not work correctly.  Last, having a separate power source lets you throw switches even when there is no power on the track. On a command layout it was most likely originally advised not to use the 18V track voltage because many of the switches only have 14V light bulbs in them as well. 

Edit:  A bit of research into the SC-1 seems to show these are pretty finicky devices as well. heres some info on them from a thread a few years back.  

JGL

Another good reason for separate power is the switches draw a spike that can be several amps, and engines with electronics frequently react to these coming down the tracks.

Thanks for replies. So to do that you would need to isolate/insulate the switch?  Wouldn't that impact the command control when the engine is on the switch, or is it still receiving that signal via the ground through the SC-1?

Your accessory power for TMCC devices should still have a common ground to the outside rail, but you wouldn't be powering the switch or SC-1 from the track power.