Gypsy Moth wrote:
I have low voltage landscape lights in my yard. There was a break in a long
run. I spliced it together and covered it with vinyl electrical tape. A
few days later, it looked like it had coroded or burned through at the
splice. The wire fused ends were covered with green corrosion. This has
happened twice at the same spot. Any suggestions as to why this is
happening and what to do about it?


All moist soil is going to be conductive, yours may be more so than is
typical. Heavy fertilizer application?

Also, under the assumption that you have a step down isolating
transformer that provides the low voltage I'd check to make sure that
one side of your low voltage lighting circuit is grounded. It is
undesirable and unsafe if the secondary winding is floating w/r to ground.

Vinyl tape is inadequate for buried applications. There are crimp
connectors available that are made for wet, or buried applications.
They're gel filled and will usually resist the intrusion of water.