DIY LED - GFCI issues

[karimwassef]

My fixture is done and works great. I used LED stars mounted on an aluminum frame. During the build, I had a little trouble with thin solder bridges to the aluminum frame causing some voltage on the aluminum. It blew some LEDs but I replaced the lights (stars are epoxied, but I can resolder the actual LEDs.) I cleared the bridges and grounded the fixture.

This caused the GFCI to blow, representing stray voltage on the frame. Cleared some more bridges (sloppy solder work, I know), and finally got the ground current under the mA rating for GFCI and it all works!

So... Burn-in for 6 hours ... Full power all on- fans going... Temperature under control (40C or so)... All good. Then, GFCI trips...

What would cause a 6 hour delayed GFCI?

 

[n2585722]

Heat expands things. Recheck all soldier connections. You have leakage current to ground. It may be one of your drivers if they are AC line input. If not then re check your power supply.

 

[karimwassef]

The power supplies are all in closed adapter boxes (no solder, no access). They have built in drivers so the only assembly is the fixture.

The temperature never got over 40C.. Not much expansion from room (23C)... But that is the only variable other than time.

 

[karimwassef]

It gets worse. One line is dead - checked it and found 10 out of 34 LEDs blown. Of those 10, 2 failed short...

This line worked fine for 6 hours...

The power supply is constant current 520mA rated to 130V & 90W and I'm only running it to 120V (3.5V per). 5 similar setups are running without issue on the same fixture.

The only difference is that for the first 3, I put Mylar tape under the interconnects on the stars (no issues at all). The last 3, I forgot and now they're blowing.

 

[karimwassef]

Also weird is that the blown LEDs are all over in the sequence:
1, 3, 6, 7, 10-15, 18, 20

If it's a problem that only occurs after hours of running, how do I debug?

 

[karimwassef]

The top row is the blown line. The two little dots on the square corners show the ones that are dead

<a href="http://s1062.photobucket.com/user/karimwassef/media/54FC0BFA-DD45-46AA-85B4-0D65EAD3AE1F_zpsivgvyotl.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/54FC0BFA-DD45-46AA-85B4-0D65EAD3AE1F_zpsivgvyotl.jpg" border="0" alt=" photo 54FC0BFA-DD45-46AA-85B4-0D65EAD3AE1F_zpsivgvyotl.jpg"/></a>

The Mylar tape is over the terminals on that line. On the one below it, it's both below and above.

After the Mylar, I use 3M reflective tape. I do this on both good and bad lines.