To ground or not to ground?

[TheJackal]

PC version, do you really need to hook up the ground wires since incans and led's only use 2 wires? Or should you ground from the home to the controller, but from the controller to the lights isn't necessary?

I hope my question is clear...

[john fulkerson]

is best to ground the plug in you are using most lights only have 2 wires hot and neutral

I make sure all my lights are plugged into a gfci receprical

ive tested some lights and a snubber is good for end of electrical it keeps the power from jumping back and forth if theres a ground

[john fulkerson]

has anyone tried a diode at the end to let the power go only 1 way and not backfeed?

[TheJackal]

?

[Bernie]

I would definately ground from house outlet to each controller if the box is  metal.  It's only one extra wire. Better safe than dead.

 

 

Bernie

[TheJackal]

I would definately ground from house outlet to each controller if the box is  metal.  It's only one extra wire. Better safe than dead.

 

 

Bernie

Agreed. What about the dongles out to the lights?

[k6ccc]

No need to run ground to most lights. The vast majority of the lights that we use are only 2 wire (hot & neutral) anyway, so no point in running a 3 wire cord to them. However, if you end up using a lighting fixture that has a 3 wire plug (and good bet that it's got a metal shell of some sort) I would run a ground to it.

[a31ford]

I'd like to add to the ground thing.....

 

 IF you have steel in the display eg: wireframe deer or buildings I would ground THEM, do NOT assume, it might kill you.

 

ALL my wire frames have ground lugs, a 2ft chunk of stainless rod (1/4" or 3/8") in the ground (even dig a trench and LAY it in , if you are worried about underground cables and gas lines), trench should be 6" deep minimum,  and a chunk of #14 or bigger solid wire, from the steel to the rod and a burndy nut on the rod will work. (like what they use for the water pipe to the electrical box).

 

Greg Manning

[steve synek]

I'd like to add to the ground thing.....

 

 IF you have steel in the display eg: wireframe deer or buildings I would ground THEM, do NOT assume, it might kill you.

 

ALL my wire frames have ground lugs, a 2ft chunk of stainless rod (1/4" or 3/8") in the ground (even dig a trench and LAY it in , if you are worried about underground cables and gas lines), trench should be 6" deep minimum,  and a chunk of #14 or bigger solid wire, from the steel to the rod and a burndy nut on the rod will work. (like what they use for the water pipe to the electrical box).

 

Greg Manning

 

I'd like to add to the ground thing.....

 

 IF you have steel in the display eg: wireframe deer or buildings I would ground THEM, do NOT assume, it might kill you.

 

ALL my wire frames have ground lugs, a 2ft chunk of stainless rod (1/4" or 3/8") in the ground (even dig a trench and LAY it in , if you are worried about underground cables and gas lines), trench should be 6" deep minimum,  and a chunk of #14 or bigger solid wire, from the steel to the rod and a burndy nut on the rod will work. (like what they use for the water pipe to the electrical box).

 

Greg Manning

 

Greg

 You got my attention...........what do you think you are gaining from your mini grounding electrodes? 

As an electrical inspector, I don't see the risk and reward for the extra effort in safety. 

  Do you get a lot of lightning strikes?

 

Steve 

[Max-Paul]

But if the wire frame has spikes on it that are driven into the ground. Then really no ground wire required. Now if the wire frame is suspended on wires to trees or wooden frame. Then yes I can see the use of a grounding wire. Grounds to the controller is good if you have the high power heat sink or if you have a pro controller in a metal box. Ya, there is a place for ground wire. Might even run a ground to the low wattage heat sink. Cause if the triac case was to have a short from the hot gate to the metal tab you could touch the heat sink and get zapped. But again no need for a ground leaving the controller cause I have yet to see a set of light that are grounded.

 

Its all in the Ground Fault!

[a31ford]

The earth here is frozen by halloween ( most years) so my wireframes do not have spikes on them, it would bend the heck out of them trying to pound on the bottom rail.

 

The reason for the ground rod is for personal safety, (touching a live frame) because of a frayed cord. GFI's when you are standing in 3 or 4 feet of snow do NOT do the job intended

 

Total snowfall  most years, exceeds 7 feet around here, last year was in the 9-10 mark.

 

 

Greg Manning

[Max-Paul]

Well if a GFI wont fire cause you are not conducting enough current to ground cause it is frozen or the snow will not conduct. Then the question is mute. If you are not conducting enough to trip the GFI, then you are not being shocked enough. Just tingled. 

[Steven]

On the Gen 2 PC boards (in LOR plastic cases), the ground wire does not go to the heat sink, just to a metal bracket in the plastic case, then to the 16 pigtails. Since most of my lights don't have 3 prongs (one exception is a floodlight in a metal fixture), there is no reason to connect the ground. A few years ago I bought a bunch of 16-gauge 2-conductor orange outdoor cable, that I use to power many of my controllers.

 

In an appliance with a metal case (such as the 1602), the purpose of the ground wire is to cause the breaker to trip if something goes wrong and the hot wire shorts to the case. (Or even if it doesn't draw enough current to trip the breaker, grounding the case will keep it at a safe voltage.) In a plastic case, this can't happen, so the ground is useless.

[a31ford]

CAn we look "Further down the road" Please ? As in toward the lights themselves, If one is using  steel wireframes, the wireframe itself, should be grounded.

 

Greg

[Ken Benedict]

Last year in the forum, several people discussed electrical "leakage" in incandescent mini light strings that were wrapped around steel tomato cages and were causing GFIs to trip. Seems it was caused by "micro cracks" in the insulation and the cumulative leakage was enough to trip the GFI circuits.

 

The solution was to raise the steel tomato cages off the ground, usually with wooden supports, and insulate the frame from the ground.

 

See: http://forums.lightorama.com/index.php?/topic/26679-mini-trees/?p=251903

 

and: http://forums.lightorama.com/index.php?/topic/18897-gfi-tripping/

 

and: http://forums.lightorama.com/index.php?/topic/24618-tracking-down-a-short/?p=232247

 

and: http://forums.lightorama.com/index.php?/topic/20728-let-the-building-begin/?p=205237

[Max-Paul]

Ken, thats the reason I dropped back and punted. AKA GFI to protect one from a short or should I say a short to you and ground. But ya, you might have to raise your wire frames to include tomato cage mini trees if that is what it takes to keep your GFI from tripping. Could be micro cracks, water in the socket making a path to the wire frame. Or it can be capassive coupling that is the problem.

[Ken Benedict]

Yes, good observation.

 

I enjoyed reading your research, in the related posts above, and what you found out.

 

Very helpful and keep contributing whenever you can.

[steve synek]

CAn we look "Further down the road" Please ? As in toward the lights themselves, If one is using  steel wireframes, the wireframe itself, should be grounded.

 

Greg

Greg

 Per the National Electrical Code the new term is bonded, as in connected to a continuous metal path back to the location of the over current device. (The term "grounded" should indicate intentionally connected to the white wire, "Grounding" or the new "bonding" should indicate connected to a steel raceway, a green or bare wire back to the origin of the circuit).  The intent for bonding is to trip the fuse or breaker. For branch circuit operation I would highly recommend GFCI protection and proper bonding,  For what we do (blink the lights) intentionally making a connecting to earth is not a requirement or recommendation per the code.

  Insulation and isolation are acceptable tools if used properly.

I agree with Ken and Max.

 

I can't decide if I want to punt and walk off the field or stay and make a tackle

  

Steve

[a31ford]

Hi People,

 

The terms we are using (Grounded and Bonded) In my Country are the same, Grounded means the 3rd pin in a duplex receptacle (and green or un-insulated wire), HOWEVER, I will also explain something else.

 

I have my own pole mounted step-down transformer (feeds ONLY my home) 16Kv to single phase 3 wire 120/240V there is NO other home, and the main overhead wire goes ONLY to my transformer.

 

As Per MY electricity supplier, I am better off, to Ground (To earth) any steel on my christmas decorations, there-by NOT creating ground loops, within the cables coming FROM (NOT TO) my lighting controlers. The cables coming TO the controlers still need to be grounded, even though the cables coming out, (generally) are only 2 wire. (I use a ground rod at each controller cluster as well).

 

TO Prove if a ground loop is present within a controller, or set of controllers (this would cause an offset voltage on the neutral (White wire in North America)). A simple test with a DMM (NOT analog meter) can be preformed using the following:

 

One wire of the DMM (Digital Multi Meter) goes to the green or Ground terminal, the meter is set for AC voltage 200 or so), the other meter lead, is touched to any steel in the display that is in contact with earth (dirt) or grass. ANY voltage reading will indicate a ground "loop". A second test is to set the DMM to DC voltage and repeat, voltage would indicate an "offset" voltage, (this is also a problem).

 

Ground Loops where a real problem with older tube type audio amplifiers, the fix was to have only ONE ground point for any wiring in the amplifiers chassis.

 

Ground Loops in RS-485 serial communications will cause "strange things" to happen with the data being transmitted, "drop-outs" and random "Chatter", are good examples..

 

Ground Loops within 120/240 VAC wiring will cause "floating" reference points for Neutral, this in-turn can cause a bias voltage for the electronics within the controller itself, causing random problems.

 

What's the worst, is moisture, it will cause questionable grounds to ground when wet, and float when dry, SO, if your system does OK, after rain or dampness, BUT is strange, when dry, I would look for questionable grounds, or floating grounds (Bonding), as Steve calls it.

 

Remember Steve,  I live in a different country.....

 

FWIW, I agree with your term "Bonded" , however, my display will be covering some 220,000 square feet, (550 x 400), bonding can, (at these distances) become a conductor itself, unless bonded to "earth" at BOTH ends, and not just the supply end. and this is exactly what I am doing (both ends), wire frames, and controllers, as well as a bonding cable back to the service.

 

I live on 18 acres, ground effect IS an issue for my area.

 

Greg

Edited July 14, 2013 by a31ford

[plasmadrive]

Hi People,

....

 

Ground Loops within 120/240 VAC wiring will cause "floating" reference points for Neutral, this in-turn can cause a bias voltage for the electronics within the controller itself, causing random problems.

 

What's the worst, is moisture, it will cause questionable grounds to ground when wet, and float when dry, SO, if your system does OK, after rain or dampness, BUT is strange, when dry, I would look for questionable grounds, or floating grounds (Bonding), as Steve calls it.

Not so much me thinks.  The electronics are fed by a transformer which isolated the secondary from the primary completely.  The Triacs are isolated via opto couplers.  Unless there is some sort of physical reference back to ground that part of the circuit relies on.. there will be no "bias voltage for the electronic"  Remember, the controller's transformer does not use ground as a reference in any way.  Ground can fly all over the place or not even be there and the electronics on the PCB won't care.  Now there are exceptions to that... but not many, and I doubt they have anything to do with the way the LOR controllers are built.   (Disclaimer:  I have not seen a schematic for the board, but I have designed and built many similar products.  I am going by "best practices" for design only).  However, with the types of distances Greg is talking about, the ground can ride offset of the neutral by some value and the zero crossing of the triacs could be where the "random problems" come in. (you could call that a bias of sorts if there is a path back to the load).  If that is the case, you could actually be drawing current from ground and that is a bad thing..  GFCI will trip if that is the case.. providing you have them.

With that said, if you have a proper bonding from ground to neutral at the meter main and your ground is of low enough resistance, most people should be fine if all grounds reference back to the main ground.. at least for physical safety.  With all the cord Greg is using, he can get ground offset voltages enough to give ya a bit of a shock under certain circumstances, especially wet ones. 

Overall Greg, I agree with your outcome, I am just being a bit picky about the terms of the electronics... sorry.. but trying to stay technically accurate... or I am full of it completely.. One of the other.. I forgot which!