Low Voltage Lighting (Malibu lights)

[res0wutv]

I have a 200 Watt transformer running 35' of 16 gauge cable to 7 lights of 101 Watts(total), then it is split off to another 25' (16 gauge) for 4 more lights of 40 Watts. The first 7 lights always work fine, after the split my 4 other lights work for about a minute then turn off. I checked the split with a DVM and I'm getting only 10 Volts at the split. Why the voltage drop?? I've change the split twice (butt splice) and it doesn't fix it... I've also try another transformer with the same results... Seems to me the cable is causing the voltage drop.... Any ideas? Thanks..

[Chris Lewis]

According to :

Copper wire has a resistance to current flow.

If you placed a 12A load (140W) on the end of 60' of 16ga wire, the voltage will drop 5.8V. Given that the lights are distributed across the wire, it won't be that much. But it'll still be significant.

16ga is too light for this load and distance. One way to fix this would be to run a new wire from the transformer to the second batch of 4 lights. Since you've split the load, you could use 16ga for the new stretch.

Most of the time I use 14ga for this reason.

The "going off" of the second string very much points to a defective wire or connector at the joint, nothing to do with the transformer.

[Jeff]

[gfretwell]

The insulation piercing taps they use in Malibu lights are crap. If it just tagging one light you can usually find the problem pretty easy but any taps and splices should be done with a better device. Those silicone filled splices boaters use are pretty good for low voltage in the weather.