- low voltage cable burning at the SPLICES ?!?! wtf ?!?

hey all,…
new to this board-- but am baffeled at my dillema I’m experiencing.

I installed a 600 watt transformed on this pond, and lights with wattage that does not exceed the 600 w max.

here is the weird part----
lights worked great for 6 months. No problems. Now … they seem to be burning at the splice points. I had to splice the cable from the back of the light-- to low voltage cable that then runs to the transformer.

I noticed that the cable I bought was heavy duty-- but rated for 240w per leg coming out from the transformer.

If I was – and I think I am-- exceeding the watt the line can handle-- why woul’nt the line burn up all along the line ? why just the splice point ?
I’m taking is is BURNED and CHARDED ! :frowning:

please help :frowning:




Send us a picture of the damaged wiring area. It may help.:slight_smile:

And do you know the wire sizes used?

My guess without pictures is that corrosion has happened at the wire splices driving the resistance up. Higher resistance means more power loss at the connection and therefore more heat. Try cutting the wires back to clean copper and then use wire splices with built in sealing compound to keep corrosion at bay.

Not sure of your voltage from the transformer but 24 volts is a good guess, therefore 600 watts at 24 volts is 25 amps for a resistive load (like lights).

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I agree with Ronald .If you do not have at least #10 wire then this could be where you problem is comming from . Did you add more lights or is all that came with the system.
If you added more lights then you should have come from the trans. with another feed .
This is what it sounds like to me ./ More info needed . Roy Cooke

If this is a 12v transformer that is more like 50 amps.

Most (not all) low voltage lighting transformers have mutliple taps…11 volts all the way up to sometimes 20v…this is so the PROFESSIONAL installer of the low voltage lighting can make sure to get 12v at each fixture…12v is what the bulbs are rated for…in most cases…lower voltage results in longer lamplife but dimmer light…high voltage results in shorter lamp life…and sometimes fires in the landscaping mulch.

In some cases it is possible for higher voltages to exceed the capacity of the low voltage wire and it will show up at the connections…or at the fixtures resulting in damage to them as well…

Check your voltages…and the fixture ratings…if in doubt call a PROFESSIONAL…

It sounds like you have all of your lights connected to one cable. You may not be exceeding the transformer 600 watt capacity but you may be exceeding the cable rating. #12 wire=20 amps , #10 wire=30amps. Add up the wattage of the bulbs connected to the one cable and divide by the voltage tap you are connected to at the transformer. (likely 12,13,or 14.) Say the bulbs add up to 300 watts and your on the 13 volt tap. You would have 30 amps on the wire and would need a #10 wire. It would be better to split the amount of lights on one cable and keep the amperage to no more than 80% of capacity.

You can add cables up the maximum wattage that your transformer will tolerate (600 watts). As was already posted, the cable is melting the insulation at the splices because this is where the most resistance is in the wire. As Tony stated make sure you have between 10.8 volts and 12 volts at the lamp for maximum life. You will need a voltage meter for this. Also, use a anti-oxidant on the connections and make sure they are nutted TIGHT. This should correct your problem. Low voltage lighting is relatively safe but can build up a lot of heat in the wire due to the resistance from the low voltages.

My MIL’s outside lamps are connected to a very good transformer, that has 12V and 15V options. Currenly using the 12V.

10 lamps on the string. The bulb package she has for replacements says " 12.80 Volts, .92 amps 11.65 Watts"

The write nuts connecting the power/lamp pigtails/wire to the next lamp melted. Wires corroded. Cut and cleaned and things appear better. However, a previous poster put out a formula that has me confused as to wire# and using the 12V or 15V out.

The pigtail wirtes are smaller than the wire used to tie the 10 lamps together.

These lamps are 20 years old.

Thank you!

The 15 volt output would be used to compensate for longer runs.

Fixture wires are normally smaller than the circuit wiring.

Loose or corroded connections will heat up.

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Made in China.

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