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Monday, February 08, 2021

Electrolier Electrical Grounding Test

 Question: May AC and DC share a Ground?

Specifically, may the 3 volt DC from the LED lamps ground to the same post that is powering the 15 volt AC trolley trolley overhead?

These Electroliers were a lot of work to construct. I really don't want to blow out the bulbs. But they perform two duties. One, they are street lamps that illuminate. Second, they provide support to the overhead trolley wires. And that's where the AC+DC concern comes in. 

    There wasn't a concern when the layout was a DC layout. 3 volt DC and 15 volt DC grounding together is fine. But now that the layout is DCC, the overhead is AC.  So the DC LED's in the lamp are grounding to the AC pole.

So before I install the trolley span wires between the Electroliers, I'm going to perform a little test first to make sure this AC/DC mixture doesn't blow the LEDs:

Here is the set up:

1. Clamped a brass pole the the layout.
2. Installed the 3 volt DC circuit:
    a. Soldered the negative lead of a LED to the pole.
    b. The positive lead of LED with resistor is connected to a battery.
    c. The negative lead of the battery connected to the pole.
3 Installed the 15 volt AC circuit:
    a. Soldered a wire from DCC command station to the bottom of the pole.
    b. Soldered a wire from top of the pole to the overhead.
    c. Connected a return wire from the track to the command station.

    Then I powered everything up. The LED lit. A trolley was placed on the track. Turning its headlight on and off as well as starting and stopping the car seems to have had no effect on the brightness of the bulb. Which means both AC and DC was flowing through the brass pole with no visible effects to the LED. So I think we are all good for safely installing span wires between the Electroliers.

Yes sir! All good to safely install span wires!



  1. Looks incredible. As I started again working on my layout, I wonder how people find the time to actually do all this stuff. Thanks again for the motivation :D

    1. I started the layout in the 1980s! I've been building it at "tinkering speed".