Uncoupler shorting out main line

Your 2 AC power supplies are out of "phase".  You need to reverse one of them at the wall outlet not a easy job with plugs today.

Have you made sure the PowerHouse 180 Watt and CW-80 transformers are in phase with each other (aka. phased)?

If I recall correctly, some versions of the CW-80 and some PH180s had reverse polarity on the output terminals.  With the CW-80 disconnected from the track, and both transformers turned on, measure to see if there is voltage between the PH 180 Common (outside rail) and the common (black) on the CW-80.  If so, you can reverse the red and black track connections on the CW-80 to get things working correctly.

I tried reversing the leads on the CW-80 but got the same result - instant short. So then I hooked up an old CW-80 to power the track and a new CW-80 to the uncoupler. This worked fine - no problems with shorting. However, I plan to run 3-4 trains at once so the CW-80 won't have enough current for track power (hence the PH 180). It does look like the PH 180 and the CW-80 are out of phase somehow but both plugs only go in one way. If reversing the leads didn't solve the problem how can it be corrected?

Maybe check the connections to the uncoupler.  If you're using Fastrack, the connections are really close together and some of the connections are partially hidden.

In this picture, Orange is Aux Hot In, and the Gray wire is Aux Ground In.

I double checked the uncoupler wiring  - it is correct. I also tested the transformers to see if they were out of phase but when I attached the grounds and the hots there was no short. I could get a test light to illuminate by attaching it to the PH 180 hot and CW-80 ground with both commons connected. Doesn't that mean the transformers are in phase? If so, what else could be causing the problem??

To check phase, you need to verify that there is No voltage (or less than a couple volts) between the Common output terminals of the different transformers.

Try check out this Tutorial from @MartyE

http://www.martye.com/TipsandTricks/TipsandTrick2.htm

In that tutorial using postwar transformers as an example, Marty suggests reversing the wall plugs (120 volt) to change the polarity so that they are "in phase".  Since the PH180 and CW-80 are modern transformers with polarized wall plugs, if they are "out of phase" with each other , the best way to reverse the polarity is to swap the track connections on one CW-80 at a time between its red and black terminals, keeping the connections to the PH-180 the same until the polarities between these transformers is in phase.  Once those two transformers are correctly phased, more transformers can be added by keeping the previous connections the same and repeating the process of checking and correcting if necessary the phase of each new transformer added.

Also note that the phased Commons from different transformers, whether they are actually red or black should be connected together.

I checked and there is 18.6 volts coming  from both transformers but no voltage when I connect the two grounds to my multimeter.  So if that means the two are not out of phase I am left wondering what could be causing the uncoupler to short out the main line. BTW, I also have my switch tracks powered by the CW-80 and they work fine with the PH 180 - no problems at all. Just that darn uncoupler!

From what you're describing, it sounds as if the transformers are phased correctly.

Which uncoupler do you have?  Can you post a picture showing the connections to it with wires labelled?

It is a Lionel Fastrack uncoupler, I thought maybe it was defective so I got another one but it does the exact same thing, which makes me think its not a product flaw.

Here is a photo: the white wire is aux hot and the green wire is aux ground.

With the uncoupler disconnected from the track as you showed it in the picture, try operating the uncoupler button to see if it shorts the transformer, I'm guessing it won't.

Since you have a multimeter, next with the transformers powered on,

1) check the voltage first between the two places indicated in this picture by the ends of the red arrow.

2) check the voltage second between the two places indicated in this picture by the ends of the black arrow.

EDIT: Both should read at or near zero volts AC.  #2 should read at or near zero volts AC, #1 should read the voltage difference between the Hots of the two transformers.

Last question:

3) are the Commons (grounds) from the two transformers tied together somewhere near the transformers?

I tried operating the uncoupler when it was removed from the track - no contact with the PH-180 powered rails but it did still short it out - Hmmm. Measuring voltage from aux in to center rail I got about 10 volts, from aux ground to outside rail no volts. Not sure what this means?

At this point, it seems that there may be something mis-wired in between the transformers, track and the uncoupler.  My suggestion would be to trace wires and make a diagram showing what connects to what.  This may help us identify what may be errantly connected underneath the layout.

Beyond this, I'm out of ideas for now, without seeing more.

I checked the wiring again. The PH180 taps into bus lines around the layout that has 10 feeder wires (5+ and 5-)  going up to the tracks. I have had no problems running trains around the track. I also checked the direct lock on and it has the + feed connected to the A terminal, the - feed connected to the U terminal and the TMCC controller wire connected to the clip. The uncoupler is wired directly to the CW-80 with no other connections to it now. It seems really weird to me that the CW-80 connected to the uncoupler can short out the PH180 track power even when the uncoupler is disconnected from the track. Shouldn't they be two independent circuits when disconnected? By what means could the heat from the coil be transferred to the PH180 circuit??

With the uncoupler removed from the track, the only way that it could trip breaker in the the PH-180 is if there is some electrical connection between it's Hot and Common when the Uncoupler is activated.  From your description of the wiring, there is no connection, but the reality of this issue indicates that there is a direct electrical path somewhere.

I decided to completely separate the uncoupler from the wiring underneath. Here is what I did:

The CW-80 has its leads connected to the uncoupling track as shown. There are no other wires connected to the CW-80 and the uncoupling track is not connected to any of the PH180's track (the PH180 is underneath). I press the button and it takes a second or two but it still trips the direct lock on's breaker! I am sure I am screwing this up somehow but for the life of me can't figure out what is wrong. You can see in the photo all of the connections to the CW-80 and there is nothing that could be crossed with the PH180 but somehow it still shorts it out.

Update - After trying everything I could think of, I finally moved the CW-80 to the other end of the layout and plugged it in to a different socket. It seems to be working (at least for now) as I can operate the uncoupler for a few seconds without shorting out the HP180. I don't understand why that made a difference and it may not last but it seems to be working now. I'll check it again tomorrow. Thanks to all who replied and to SteveH especially for hanging in there with me.  Next, I'll ask for ideas on fixing my other CW-80 which I managed to fry after having it for about 30 minutes trying to sort out the HP180 short! Ultimately, you have to pay for your education one way or another but at least I think I'm learning.

@Robert Earl posted:

I

The CW-80 has its leads connected to the uncoupling track as shown. There are no other wires connected to the CW-80 and the uncoupling track is not connected to any of the PH180's track (the PH180 is underneath). I press the button and it takes a second or two but it still trips the direct lock on's breaker!

You say it's popping the tmcc lockon. I wonder if the lockon isn't a weak link here?

The lockon will trip way sooner than the PH 180 breaker. I added a lockon to my layout after I had run without one for several  years because the lockon came free with a 180 brick I picked up.

The lockon will pop for all sorts of unnecessary reasons.  I've been considering removing it from my layout.

The fast acting breaker in the 180w done a fine job of protecting trains on its own.

That's a good point. I wondered if the lock on was playing a role and thought about by passing it to see if it helped. Is there something readily available that can plug in to the molex connector and then have the two wire come out the other end?