GFCI issue

[Brian W]

I have a 25 ft. mega tree that uses 7 LOR controllers split over four GFCI extension cords. http://www.lowes.com/pd_145277-33536-30438062___?productId=50394552&pl=1&Ntt=gfci

Over the 8 years of running this tree, I have learned to turn female outlets down, keep externsoin cord plugs off ground etc. with good success.  I was travelling this weekend and discovered that all four GFCIs accociated with the mega tree were tripped.  The center pole is 1.25 water pipe that is inserted in a pvc sleeve buried 2 feet in the ground.  With clay/slate soil, this area became a pool of water with the abundance of rain that we have had of late.  Is it reasonable that the metal pole and the 16 metal stakes in the ground that form the bottom circle of tree combined with the standing water would trip everything. (with this much water, thank goodness the GFCIs are working as they should).  The articles regarding GFCI trips and metal tomato cages on the ground led me to this conclusion.  If this is reasonable, are there any good solutions to this problem?

 

Thanks, Brian

[k6ccc]

Certainly a good possibility.  Especially if either of the following apply:

 

1)  Some or all of the cords from the controller are in close proximity to the center pole (such as zip tied to the pole).

2)  The light strings are supported along steel guy wires that are attached to the 16 metal stakes.

 

Glad to see someone who understands that a GFCI tripping is doing what it's supposed to do.

[Brian W]

Thank you for your thoughts.  There are no cords contacting the center pole but the light strings are supported by steel guy wires running from center pole to metal stakes. Other than hoping for less rain next season, any thoughts?  I don't know enough about electricity: will concrete conduct electricity?  In other words will I have the same situation if I imbed the PVC pipe/sleeve in concrete or is there some type of insulating material that would work and still provide strength? Or would that create a dangerous fixture?  I could replace the metal stakes with some other type of non-conducting material but they would have to be sturdy enough to drive thru slate/clay.

[Mr. P]

I ran into the same issue with all the rain we have had this year on my mega tree, I even use the exact same GFCI cords that you do. Since I use the same light strings for my tree every year I hot glued all my female plugs closed to keep the water out didn't have an issue after that.

[k6ccc]

Thank you for your thoughts.  There are no cords contacting the center pole but the light strings are supported by steel guy wires running from center pole to metal stakes. Other than hoping for less rain next season, any thoughts?  I don't know enough about electricity: will concrete conduct electricity?  In other words will I have the same situation if I imbed the PVC pipe/sleeve in concrete or is there some type of insulating material that would work and still provide strength? Or would that create a dangerous fixture?  I could replace the metal stakes with some other type of non-conducting material but they would have to be sturdy enough to drive thru slate/clay.

 

Concrete does not conduct very well, however since you said that the center pole was in a pool of water after the rain, no amount of insulating it will keep it from being pretty well connected to ground.

 

The steel guy wires from the metal stakes to the center pole are going to be fairly well grounded since they have at least a decent ground at both ends.  Since you said that the light strings are supported by the reasonably grounded guy wires, I'm going to guess that capacitive coupling from the light strings to the guy wires is the crux of your problem.  when it rained, the guy wires became far better grounded. 

 

There are a couple of solutions.  I don't recommend replacing the stakes as it sounds like you need hefty beefy stakes for mechanical reasons.  You can isolate the guy wires with either an insulator at each end.  Look at the insulators on guy wires on a power pole for what I'm talking about.  You obviously don't need insulators that heavy duty.  If you're not pulling too much pull on them, you could build them out of plastic bar stock or pipe.  One note is that if you look at the utility insulators, the wires pass through the insulator such that if the insulator fails, the guy wires don't become separated.  This is an important safety concern.  You don't want a failure of the insulator to result in your tree falling over because of a failed guy wire.

 

Another option is to use a rope instead of steel cable for the guy wires.  There are a couple considerations however.  One is that it be strong enough to do the job.  You don't want a rope that will stretch very much.  You want a rope that will not degrade in the sun or mildew when it gets wet.  There is a type of rope used by radio people for that purpose that has a name something like Philistring, but a quick search did not find it by that name.

[Max-Paul]

Here is some info to go along with what Jim was telling you about. Check out http://www.amateurradiosupplies.com/

 

Check out Egg insulators and Dracon Antenna Rope. Actually on left side under Antenna Rope. And per what Jim was saying, do not use the dogbone type cause if it breaks, the wire will not be contained and that will cause more problems.

 

I do disagree with Jim about concrete conducting. There is always enough moisture in concrete in an outdoor installation to conduct small amounts of current. Enough to cause a GFI to trip.

 

I agree that there is enough induced current from the lights to the steel wires and center pipe to cause the GFI to trip.

[k6ccc]

Max, thanks for looking it up on ARS's website.  I had done a quick look on HRO's site and not found them.  Didn't have time to do a detailed search.

 

I will stand by my statement that concrete does not conduct electricity VERY WELL - but with the center pole in a pool of water, the pole will be pretty well grounded (more likely from the dirty water rather than from the concrete).  Realizing that "does not conduct electricity very well" is a highly subjective statement.  Lightning will get through concrete just fine, but I doubt your lights are operating in MegaVolts range! 

[Mega Arch]

I like the look of a mega tree when the strands go all the way to the ground - the no trunk look. I have a sloped yard to tend with and didn't want my tree to be tilted. So I used a PVC ring with the below anchors from Christmas Light Show. I used 1/4" all-thread rod to make the ground to ring a longer distance as it sloped. One additional thing it provided was an insulator between the 16 light strand guy wires. You still have the 4 pole guys that could add to your leakage, but this takes 16 cables out of the GFCI issue....

http://www.christmaslightshow.com/Mega-Christmas-Tree-Ring-Anchor.html

 

[Brian W]

Thank you for the link on the insulators.  I was having no luck with my online searches but I now know exactly what you are talking about.  Just curious, the steel cables currently connect to an eye-bolt attached to the stake via an S-hook.  Would wrapping this eye bolt and/or S-hook in electrical tape where they touch do the same as the insulators described above?  

 

This area of my yard is sloped a bit, but I have a landscaping valve box that hides the PVC sleeve in the off season.  The soil level adjacent to the sleeve is lower and allows pooling inside the valve box.  I was thinking of imbedding the PVC in concrete and bringing the level up as high as I can to mitigate the amount of water collecting there.  Not perfect, but in hopes of minimizing a problem.

 

Mega Arch - I prefer the no stand look on mine because it is a spiral and I like the look of the "sweeps" that it makes.  I am going to study the bottom of yours and see how best to incorporate in my tree next year.  Thanks.

[k6ccc]

Thank you for the link on the insulators.  I was having no luck with my online searches but I now know exactly what you are talking about.  Just curious, the steel cables currently connect to an eye-bolt attached to the stake via an S-hook.  Would wrapping this eye bolt and/or S-hook in electrical tape where they touch do the same as the insulators described above?  

 

This area of my yard is sloped a bit, but I have a landscaping valve box that hides the PVC sleeve in the off season.  The soil level adjacent to the sleeve is lower and allows pooling inside the valve box.  I was thinking of imbedding the PVC in concrete and bringing the level up as high as I can to mitigate the amount of water collecting there.  Not perfect, but in hopes of minimizing a problem.

 

 

I would not depend on just some tape to insulate it.  It sounds like there is not much you can do to prevent the center pole from being grounded.  I suspect that from a lightning standpoint, you are better to have it well grounded - but we hardly ever get lightning around here so I'm not the expert.  So you will need to insulate the strings from the pole and anchors at the bottom.  I would put an egg insulator at the top and bottom of the steel cables and your problem should completely go away.

[Brian W]

Thank you for all of the help.  One last question:

 

My tree is topped with this star: http://www.christmaslightshow.com/Outdoor-Christmas-Tree-3D-Star-topper.html

 

This is screwed on top of the assembly for the crank head on top of the pole with the rope light attached to the frame with zip ties. what can I do to remove this as an avenue for a fault? 

[Mega Arch]

Brian,

 

I'm using that same 3d Star and you can see in the pictures, lots of ice this year. I strongly suggest you use the pvc ring to insulate the strands as I mentioned previously. Then the next thought is what kind of light strands are you using? You said you have all four GFCIs tripping. I have the 68 strands of mega tree, all my house c9s & icicles, and the 40 front luminaries running through 5 controllers on one GFCI. Just wondering if you are using sealed leds or not?

 

Also, those portable GFCIs can get some nuisance tripping. GFCIs look for imbalance between the load & the neutral. If you have other loads on the receptacle besides the loads going through the portable GFCI, it can be a safe circuit but is tricking the GFCI into believing it's seeing leakage. Another thought is they are not GFCIs for life. You said you've been doing this tree for 8 years. They can get a build up of internal corrosion and just may be time to change out the GFCIs.

 

Good luck.

[plasmadrive]

Max, thanks for looking it up on ARS's website.  I had done a quick look on HRO's site and not found them.  Didn't have time to do a detailed search.

 

I will stand by my statement that concrete does not conduct electricity VERY WELL - but with the center pole in a pool of water, the pole will be pretty well grounded (more likely from the dirty water rather than from the concrete).  Realizing that "does not conduct electricity very well" is a highly subjective statement.  Lightning will get through concrete just fine, but I doubt your lights are operating in MegaVolts range! 

Actually concrete conducts just fine for a grounding system component.  Ever see a Ufer ground system?   Works very well and is very common.  It is actually in the NEC and required in some states.  I have a ufer ground for my shop. 

 

"In 1942, Herbert G. Ufer was a consultant working for the U.S. Army. Ufer was given the task of finding a lower cost and more practical alternative to traditional copper rod grounds for these dry locations. Ufer discovered that concrete had better conductivity than most types of soil. Ufer then developed a grounding scheme based on encasing the grounding conductors in concrete. This method proved to be very effective, and was implemented throughout the Arizona test site."