Case is alive

I have an XPS15 9560 and 2 weeks ago I got a TB16 Thunderbolt dock.  I just noticed today that when connected to the dock, the outer shell of the XPS has quite a noticeable tingle.  I don't have a meter to measure it but I can hold onto the case without being thrown across the room, so I suspect it's 12 volts?  No idea really, just guessing.  

If I connect with the normal power pack it's fine.

Problems:

1) Warranty on my XPS expired like 5 days ago - of course.

2) Both of these units where purchased in New Zealand and Im currently residing in Thailand with no local (reliable ) agent or service centre nearby.

Questions:

Has anyone else experienced this ?

Is there any chance I can get Dell to look at this under (slightly) expired warranty?  

Any other suggestions?

Thanks