Outdoor LED lights trip GFCI during rain

[brucet9]

I have a big triple-trunk olive tree (trained and pruned laterally to resemble a coast live oak) whose 44 branches I decorate with 84 strings of M5 LED lights from Creative Displays.

The setup is an outdoor covered outlet, 4th in line behind a GFCI, on a circuit starting in the garage.  To that is plugged a remote controlled two-way splitter with an ordinary three-way splitter plugged into it, giving 4 connections for extension cords and light strings.  3 extension cords run up the main trunks and one connection serves lights winding upward around those trunks.  Three further extension cords run up to higher branches in order not to put too much load on lower light strings.  Light strings wind around branches until they reach the outer ends and then are distributed, densely woven, in amongst the twigs. 

Whenever it rains(admittedly not often here in SoCal), the lights trip the GFCI.  After rain stops, even when the tree and lights are still wet, the GFCI doesn't trip.  

Thinking that some water must be getting into the slight gap between male and female connections and bleeding off current.  I reasoned that if current bled between hot and neutral blades, the GFCI would see no difference and so not trip.  If a little current bled to the ground prong on one of the extension cords, maybe that would explain it, so I cut the ground prong off the remote control splitter's plug, but that made no difference.

I'm baffled as to what is happening unless, during rain, there becomes a path for current bleed from plugs of light strings to the branches and thence to earth?

Any other suggestions?

Anyone have a similar problem and discover a solution?

[dchackert]

Do you use di-electeic grease spray on any of your extension cord connections? I use it on almost all connections, especially those and the ground and I seldom have issues. We just jad rain for two days here in Indiana and nothing tripped. 

[slankard]

I’ve had the same problem with my tall trees.  I had a 200 amp service installed in 2020 and I just assumed the new GFIs are extra sensitive.  I’ve  thought about the electrical grease, but between the two tallest trees I use over 200 stings of 100 count LEDs and I thought that could get pretty messy rolling them up and storing them.  Would love feed back from th9se who do use the electrical grease, because it is getting frustrating.

[chuck]

First thing to try is elevate any ground level electrical connections.  The trick is to use a wooden stake to raise where two extension cords come together by 4-6 inches.

The real challenge is that well wrapped tree.  I'm betting there's a light string that has a wire with cracked insulation providing a way for electrical current to sneak to ground and trip the GFCI.  I'd also check those strings wrapping the tree trunk.  Look for teeth marks.  Some critters think wire insulation is tasty. 

After this season spend some quality time closely inspecting those light strings for any sort of damage.

Pros get around GFCI issues by using low voltage Christmas lights.  Look at the bottom of a tightly wrapped tree and you'll see 12-24 volt transformers.

[Scott Rob]

For me I use the yard light stakes to keep connecting items off the ground by at least 6”. In some cases I leave the cord to most of my blow mold folded up( see picture of back of wiseman and sheep). 
The do-electric grease I have a small bottle that I used past 6 years. For me I put a small amount of grease on scrap pics of cotton fabric and have a very little on male part of plug. At the end of Christmas I take a paper towel and wipe if off if there any left. 
The GFCI breakers in panel work way better in my book than outlets. I had lot of issues in 10years ago with GFCI tripping out. I spoke to Siemens rep at work and he recommended the breakers instead. He said they found over time moisture in box would damage the interworking of outlet resulting in it being more sensitive or just tripping out with little load. For me mine would not reset at all which is common with moisture damage. That’s  long but hope it helps. Also I live metro Atlanta and we have a lot of steamy days.

[Scott Rob]

The town I live in has light on over 20 trees around downtown. The current ones were put on trees about 2 years ago.(see picture one with tractor) they used local company Christmas Light etc. with really nice look lights ( see attached pics). 
Also make sure on your tree to not have female ends pointed up. Water can and has for me some issues in the past. I try to have plugs lay on branch so that less change of water getting trapped in the plugs. 
Also I really like SPT wire and outlets I have a run with a few In-line outlets for the trees and it really helps with set up.

[chuck]

11 hours ago, Scott Rob said:

The GFCI breakers in panel work way better in my book than outlets. I had lot of issues in 10years ago with GFCI tripping out. I spoke to Siemens rep at work and he recommended the breakers instead. He said they found over time moisture in box would damage the interworking of outlet resulting in it being more sensitive or just tripping out with little load. For me mine would not reset at all which is common with moisture damage. That’s  long but hope it helps. Also I live metro Atlanta and we have a lot of steamy days.

Years ago I worked with a mouse-based theme park in Orlando.  Their 4 million light display included two people that did nothing but walk around resetting GFCI plugs during damp evenings.  They ended up shifting to centralized GFCI distribution points that were weather protected and most of the power issues went away.

The GFCI in the dry breaker panel makes a lot of sense.

[brucet9]

Dampness at the GFCI is not my problem.  My GFCI is indoors, protecting a circuit including two double duplex outlets over my workbench and two outdoor duplex outlets weather resistant covers.