New way to wire arches/controllers using less wire

[Joe Piotrowski]

I just got done wiring an arch with 8 segments and 3 colors each. Ended up with 12 sets of stp2 comming out of each end of the arch. 24 wires about 10 feet long on average with 48 vampire plugs. Figured their has to be a better way.

Why do I need 24 neutrals? Why not 2? One at each end.

Lets start by just thinking of half the arch, because it uses 12 channels and will be hooked up to one controler. (other 4 channels will be used for other misc items like normal)

Each end of the arch would have one neutral that would connect to all 12 channels via a vampire plug. I would have to cut a small section out of the vampire plug for the neutral to pass threw. Each Hot would terminate at the vampire plug.

Note picture below.

This way I would only be using 6.5 10 foot long sections of STP2. (the .5 would be a single wire for neutral, then 6 sets of 2 wires) I would use the same 12 female plugs, but only 7 male plugs. 6 male plugs would be the 2 hot's for the 12 channels, and the 7th plug would be one neutral and one unused.

Of course, the controller would be wired appropriately, therefore needing less female dangles.

I figure since each channel only has one 70 light led string attached, I would not run into any current problems. STP2 is 18awg, and the light wires themselves appear to be 22 or 24 awg, since supposedly you can string dozens together.

I realize this is not for everything, but for something like arches I think it may be a good idea.

Does anyone see anything wrong with this setup? Potential problems?

Thanks

Joe Piotrowski

[George Simmons]

Wouldn't Molex connectors be even better?

[Joe Piotrowski]

Yes, good idea for the connection to the controller But I still think I would use vampires for the female that connects the stp2 to the lights. That way I'm not cutting all the lights.

Thanks for your reply, Does anyone else see anything wrong?

[De Trommelslager]

Ummm... This might not be the best plan.

In power systems, a neutral carries the unbalanced load between phases. It also completes a single phase circuit. If you have two circuits (an A & B phase) pulling 16A each, the neutral would have no current flow. Take the two circuits sharing a common neutral and let's say they are on the same phase pulling the 16A each. Your neutral would now be carrying 32A. A recipe for trouble!

In your case:

If you are using one circuit from the panel for all of the lights on an arch, then you would be fine sharing the neutral. But, for your example you are using 24 channels which would be two controllers. If each controller is on it's own circuit and GFCI from the panel, your are going to experience some frustration with GFCIs tripping.

To gang channels up on a common neutral, the following would be the only way I would advise doing it. Take your controller's banks (1-8 & 9-16) and use a common neutral for each bank. Channels 1-8 would have a common neutral, and 9-16 would have a common neutral. For 24 channels, you'd have another bank of 8, so there would need to be another neutral for those channels as well. This would ensure that you aren't overloading a neutral if you are feeding controllers with multiple circuits and should avoid a mess with GFCIs tripping. If you are adamant about going this route, draw it out on a sheet of paper so you can follow along when you are building it up, there's a fair amount of room for error in doing this in practice.

Bottom line: I strongly advise against sharing neutrals for the sake of saving some wire. Too much room for error. Best case scenario if something is wrong is you have GFCIs tripping; worst case you have stuff burning up.

NOTE: If the system is not supplied through a GFCI (it would be unwise to not use GFCI protection), care would have to be taken in this instance that things are kept absolutely straight to avoid a dangerous situation. Read: fire! My advice in this scenario; put your system on GFCI protection and don't share the neutrals. If you know exactly what you are doing and the dangers of getting it wrong... don't share the neutrals!

Edited December 14, 2012 by De Trommelslager

[GaryM]

I don't struggle with common neutral if you know what you're doing. if I'm reading you correctly you'd have a "neutral buss" that you attach to for each segment/color. If so, you can get spt females that are "pass thru", or inline connections, and you don't have to be hacking on the vampire plug.

Past experience using common neutral was that it made it too custom, and the following year, with changes made to the design of my display, I had a lot of wasted spt (aka "custom wiring harnesses") in a box. Big difference there was centralized controllers versus distributing them thru the yard.

So yea, technically you can make it work, I'd question its practicality for the long term.

[Joe Piotrowski]

Gary and De Trommelslager,

Thanks for your insight,

I plan on using this setup only for a bank of arches, all of my lights are led and my entire show runs off of one gfi circuit.

I would only go this route knowing that it only works in the above situation.

Now by asking this next question, I might be showing some lack of knowledge, but....

Since each of my controllers is set up using only one supply, then isn't each channel already sharing a common neutral? Are not all the neutrals connected together inside the controller? Only real difference I would be making is combining my neutrals before they got into the controller instead of after.

Gary,

I think I would still like to custom modify vampire plugs and not use "pass thru" ones. In my system, the hot wire would not pass thru, so I would end up having a wire exposed that was hot. I would rather modify the plug so a hole is made only for the neutral. The hot would terminate in the plug.

Thank you both, and please respond your thoughts.

[-klb-]

My thought is don't modify your controller to allow the use of fewer spt males. Either continue to use the same number & configuration, passing wires through the males, or go to a completely custom connector.

Having the hot side of a channel on each blade of a NEMA 15 connector is just a bad idea. If you ever forget a controller was wired that way, or worse, it gets sold to somebody else, you have set up a bad situation. If a normal string of lights gets plugged in, it won't light. So now someone can try troubleshooting this apparent lack of power with both leads potentially hot.

Remember, if you think this isn't that big a deal, many fatalities result from combinations of events that aren't such a big deal. For example, the GFCI that tested good at the start of the season may fail stuck on. (I have replaced a few of those) add troubleshooting this wiring scheme, thinking it is a normal controller, and then add bad safety practices while working.

[De Trommelslager]

Since each of my controllers is set up using only one supply, then isn't each channel already sharing a common neutral? Are not all the neutrals connected together inside the controller? Only real difference I would be making is combining my neutrals before they got into the controller instead of after.

Yes, each bank of channels shares a neutral in the controller itself. It is basically a buss. However, each channel has it's own neutral leaving the controller. If you start altering the wiring methods from what is industry standard, things can get more complicated and dangerous. Sharing the neutrals for a bank would work fine and be perfectly safe if it was constructed properly. Once you went that route, you are pretty well committed to the way it is set up. As klb and Gary both mentioned, what about next year or the year after? What about the next person to own the equipment?

Let's look at it from another angle, or two. What is it that you are truly saving by ganging up the neutrals? In materials, $40 or so? $100? Seriously think about it for a minute. I have taken some of those "shortcuts" that have turned around to bite me on the posterior later on, and in the end it ended up costing two or three times what it would have if I would have just done it right the first go.

From a safety standpoint; what is your deductible on a visit to the ER? And how much are you saving in materials? If you get a good shock, or worse yet someone else gets a good shock (or killed), what would that cost? Theoretically it wouldn't happen with a GFCI protecting the system, but they said the Titanic was unsinkable, too.

One last consideration... Let's for a moment say that your neighbor came by, touched your arches and received a shock that put him in the hospital. Mr. Personal Injury Lawyer (no offense intended to the lawyers out there!) persuades your neighbor into suing you for one billion dollars. On the stand, you are being drug over the coals about your wiring methods and how your actions caused the injury to Mr. Neighbor. Think about trying to convince a court that your method, which is out of the norm for industry standard, was safe and sound and that the shock was a freak accident (which it very well could have been). That's not a spot I want to be sitting in, nor would I advise anyone else to do so.

The set up would work if it was constructed correctly. But, I strongly discourage you from attempting it for a variety of reasons, both for safety and financial.

Edited December 14, 2012 by De Trommelslager

[Joe Piotrowski]

Now you have hit a the right nerve.

My motive for doing it this way was slightly financial, but also bundle of wires leaving each side of the arch is about 1 inch in diameter. I just hated that mass of wires and all the connection points.

I would have no problem using the controller the same way year after year. And if I were ever to sell, I would make sure controller was "unwired".

However I have dealt with lawyers before. Not pleasant. It doesn't matter if you did everything right, just defending it would cost a fortune.

I will wire it normally, and just deal with the mass of wires.

Thanks for keeping me straight.

Joe Piotrowski

[George Simmons]

If your motive was partly financial, but mostly an issue with all the wires, why not use CCRs for the arches? Any color(s) you want, and only one cord leaving one end of the first arch. By the time you add up the lights, the wires and the plugs I doubt there's much difference in price, but there's hours worth of difference in assembly time, and you know what they say - time is money.

[Joe Piotrowski]

Boy do I feel stupid.

My one arch is using 24 c6 led strings. (I buy them direct from china at a cost of about $11.00 a string). Then I need 1.5 controlers at $200 each. Plus lots of wire/plugs. Total cost of my 8 channel, 3 color arch about $600.00

Once CCR $250

Guess I've built my last arch

Now just need to learn to program the CCR's

[LightsinMaine]

I try to tell people that Joe, but some don't get it.....CCR arches are the way to go for conventional arches (or even better RGB stuff from China). CCRs are very easy to program as far as arches are concerned in the standard program...don't buy Superstar if you don't have to!!

http://forums.lightorama.com/index.php?/topic/23555-leaping-arches/

Edited December 14, 2012 by LightsinMaine

[George Simmons]

Boy do I feel stupid. Don't be overly concerned. Based on some of the threads I've read in the past few days, you've got lots of company...

My one arch is using 24 c6 led strings. (I buy them direct from china at a cost of about $11.00 a string). Then I need 1.5 controlers at $200 each. Plus lots of wire/plugs. Total cost of my 8 channel, 3 color arch about $600.00

Once CCR $250

Guess I've built my last arch

Now just need to learn to program the CCR's Piece of cake - you can easily learn almost everything you'd ever need to know about programming a CCR in less time than it would take you to build that 24-channel arch.