Sparks on mains powered external hdd
 

I have had this external ide housing for around as long as I have had my computer, which is around a year now. I haven't been aware of this from day one but I have been aware of it for a long time (many months) now but shrugged it off since nothing has set on fire or exploded all this time.

I am not an electrician which I why I am asking, surely this isn't normal or doing my computer anygood is it?

It is the metal bit but on the USB connection, when touched to any metal part on a PC case e.g. the back connetions plate little but visable mostly at night sparks emmit from it when rubbed along.

I will try and get a quick video capture when charged batteries.

It doesn't when machine is unplugged from mains but still does when switched off even by the power supply button.

Just checked and it sparks on the other computer too.

Sounds like you may have a short on the external case. Sounds like there's a power short going through the usb connection. I'd get rid of that case before you blow something important.

(can't edit my posts..yet) It doesn't spark when still, only when dragged across metal.

Thanks for the response.

yeah, my external caddy did that. i blamed the cheapass power supply that came with it. it should be safe, just make sure the USB is the first plug in, last plug out. i'm pretty sure it's just because the PSU is floating.

If it were an issue of power supply or wiring, would it not arc every time the circuit is opened or closed?

I'm no expert, but if the only time it sparks is when you rub laterally across a specific surface... seems like static would be the culprit?

The issues is that the metal part of the USB plug shouldn't be powered at all! Rubbing or scraping shouldn't do ANYTHING with power, because there shouldn't be power flowing to it.

Some input on this here:
http://forums.aria.co.uk/showthread....7503#post87503