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Ground burning out

I have a problem with my lighting system on my back patio. I have three ckts fed by two source leads that are attached to my Txfmr. The txfmr is an "I-Force" multi-tap 12-20V from Unique Light. One ckt has 17 10W lamps and two 30W spots (approx 50 ft wire run)connected to the 13V lug. The second ckt has 14 10W lamps and 2 30W spots (approx 70 ft wire run)connected to the 14V lug. The Txfmr says that there should be no more than 360W max per voltage source so I'm good there.

When this problem started was when it was raining quit a bit and the underground connector towers filled with water. The gnd lugs and wire were fried on the txfmr.

I moved the boxes above ground, filled the wire nuts with no-ox, and taped up tightly. I repaired the txfmr using new lug strip and replacing the 10 gauge wire gnds that were burned leading to the tx itself. All connections were soldered, crimped and sleeved with shrink wrap.
It is controlled by a light sensor and I have the source power going through a GFI outlet and timer in a separate Nema 12 box.

I tried it last night and this morning it show signs of excessive heat. Wire coating burned back about a 1/4 inch and charred on both ckts.

There was no problem with the system and worked fine with no problems for the first 7 months, then we had a really wet fall and it hasn't been right since. It took a while to find the flooded boxes as they only flooded when it was raining long and hard. I was sure that this was the problem.

Re: Ground burning out

What is the total wattage of the transformer? Are you connecting multiple cables to the transformer output? From your description yoou have connected 430 watts.

Re: Ground burning out

Most of those transformers are only rated to run one circut or the other, being the 13v, or 14v, not both together at the same time, I would run 2 transformers and call it a day, That way you can isolate your circuts and if one transformer dies you still have half of your low voltage lighting. Good Luck!

Re: Ground burning out

I'm of the same thinking as jled96 ---- in that you would use only one tap on the transformer.
Also I'll bet the model you have is the 360 watt model which is why the warning --- currently you have a total of 420 watts .

If the conductors had gotten wet then likely are corroded which increases the resistance of the the load ( which increases the amperage draw from the transformer ). When copper wire ( especially stranded ) gets wet it wicks the corrosion further up the wire. In which case you may need to strip back the covering until you get to good clean copper wire to make your splice.

Also, tape won't do any good trying to keep your splices dry under ground --- they should be in water tight j-boxes.

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