Landscape Lights Dimming Towards End of Circuit


Hi
I have recently installed 6 (35 Watt) landscape lights, on a 300 Watt transformer.
It is 12 V AC, on about 50 meters of cable.
Light number 1 and 2 perform as expected. Light number 2 is about 20 meter from the transformer.
Light number 3 - 6 is dim, but does not get progressively dimmer from 3 to 6.
Why would this be?
I am ruling out excessive voltage drop because light 3 and 6 is glowing at the same brightness.
Could this be because of a short?
Thanks
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snipped-for-privacy@gmail.com wrote:

It is voltage drop due to the length of the line. You could try adding an additional line, using heavier conductors and bringing it directly to the last fixture you currently have. Make sure you don't reverse polarity. :-) I suggest that different lamps react differently to voltage drops. Manufacturing differences and age can make some more sensitive than others.
You also may try moving the bulbs around and see if it follows the lamp or the socket. There may also be problems with poor connections. As I recall many of these use piercing wire type connections. They are subject to high resistance connections and to possible corrosion. That could also be an issue.
Good Luck
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Joseph Meehan

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Hi Joseph Thanks for the reply.
Would voltage drop affect only the last four fixtures on the line and each of them in exactly the same way?
I will check all the connections again on the weekend, these were not the piercing kind, so it could well be my fault for doing a bad job when connecting.
I will concider all your options and see how it works out.
Oh, I also wondered if LED bulbs would maybe solve my problem? I have read on some sites that they are much more tolerant in conditions were voltage drop exists.
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snipped-for-privacy@gmail.com wrote:

It would effect all lamps once the voltage drop reached a certain level. I do find it odd that four lamps would be affected the same way, but there are possible reasons You also might want to try moving the first affected and last non-effected lamps to the end; switching the end ones into their locations.

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Joseph Meehan

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Hi Joseph, thanks again. I am going to switch the globes around today. Will do all the rest of the checks over the weekend.
LOL I also have an electrical engineer on the job now, my cousin. So I am sure I will get this sorted out.
Thanks again. Will keep you posted with the progress
Joseph Meehan wrote:

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wrote:

[snip]
The OP may have overlooked this suggestion -- to configure the conductor as a loop which terminates back at the transformer. This will make all of the lights of equal brightness. As JM said -- "Make sure you don't reverse polarity. :-)" !!
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JimR wrote:

Would that be Style 6 or Style 7?
nate
(sorry, been staring at fire alarm stuff too long...)
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Hi Thanks for all the suggestions.
I switched the lights around yesterday, thinking it could be a faulty fitting or globe/bulb, still remains the same.
I will do a voltage test on the w/e and see if there is any major difference between lights 1 through 6.
There are also two connections between lights 2 and 3 that I want to check, one that joins the two cables and one of course where light 2 joins the cable.
I do not know the gauge of the wire in American standards but it is 1.5 mm single core wire. The lights are wired in parallel as it is an AC circuit, I believe there is not another option.
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The ones in the middle may be dimmer, but this is a good idea, known as "ring mains" inside UK houses.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

It also has the advantage of keeping the lights on if one connection fails.
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Two more days to go and then the problem shooting begins.
I will first try and isolate the possibility of a short or partial short in the system, that will be the least effort and the least amount of digging :-D
Then I will see if I can get my hands on a multimeter to see whether voltage drop exists in the system, if so I will maybe boost the voltage to 14V or so, then the last ligths will receive the 12V they need, but I will need a resistor on the first two lights so they wont get fried.
If that is not an option I will add a second conductor to the system and wire the lights in the loop pattern, using a higher gauge conductor.
Thanks very much for all the suggestions, will keep you posted.
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Hi
Ok who wants to take bets on what it was ?
Yeah ok it was voltage drop.
I checked the 3 connections that could have been the source of a short, nothing wrong.
So I moved the transformer roughly 15 to 20 meters down the line which makes the circuit resemble a Y. I am getting around 10V on the first couple of lights and around 7V on the last couple.
Much better, not ideal but much better.
Thanks very much for all the assistance.
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snipped-for-privacy@gmail.com wrote:

Are all of the lights and sockets the same?
Have you tried switching or replacing the lights? You could, for example, try switching lights 1 and 2 with lights 3 and 4. Actually, you might want to try switch all of the 3 - 6 lights with the 1 and 2 lights.
What gauge of wire is used?
Is the gauge the same to all the lights?
Are the lights all wired in parallel?
What is the available voltage at each socket?
I think it could be possible, incidentally, that you could have a partial short between lights 2 and 3. You could try running a jumper cable (wire pair) from light number 2 to the rest of the lights. You would have to disconnect the existing connection between 2 and 3 to do this.
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