Sparks when plugging powered usb items into macbook

[KrooKedUK]

I have just noticed recently that when I plug a powered usb item like an external hard-drive or printer into my unibody macbook that it sparks. Nothing has been damaged so far, but ideally I would like to figure out the problem before it kills the mac.

Has anyone else had the problem and been able to fix it?

 

[KrooKedUK]

Yeah it's the full length power lead I am using so it should be earthed fine. It happens regardless of the macbook being plugged in.

It just broke the signal to the external monitor I have plugged in there now when I connected the external hdd.

 

[KrooKedUK]

Yeah it's still in warranty, only a month old. You think I should take it in and see what they say?