desA

We don't wrap in cork tape. I have not heard of this. Where / When is it common to use and for what reason?

I am going to investigate electrical current. I know that it can have a big effect if the materials have a significant potential difference (e.g. copper and aluminum), but I am still puzzled how this can be the case with copper to copper contact!? Plus the fact that this section is inside the foam so there is hardly moisture for galvanic effect to take place?

I also will look at what chemicals are in the heat shrink tube and maybe this is the culprit.