Apiotek eSATA II 300 express card adapter is shocking me.

[iamjohnsname]

Hello,

I use the above adapter in the express card port of my 2011 MacBook Pro. It is connected to two HDDs in docks.

When the device is running, it seems to be un-insulated. As in, electrical current is running through the metal part - not just the connection inside the adapter but the adapter itself. In fact, touching it, or even my aluminium laptop when the adapter is plugged in, results in an electrical shock.

WTF? Isn't this very dangerous to the components of my machine?

And why is it even happening? I didn't think that power travelled along those SATA cables, only data?

-- John

 

[Timur]

It's happening because either your HD enclosure or Mac are not grounded while the other one is. Are you using a mixture of 2-prong and 3-prong power-plugs?

Besides, Macbook Pros are usually not properly grounded anyway. Once you connect them to an external display or other properly grounded device they will share the proper ground.

When you connect devices of different grounds you can get electrical sparks. The voltages and especially amperage are pretty low though (usually less than 10 volts). It can cause issues with active data-transfer over eSATA ExpressCards though (stalls or link losses, can also lead to Kernel Panics and system freezes).

 

[iamjohnsname]

It's happening because either your HD enclosure or Mac are not grounded while the other one is. Are you using a mixture of 2-prong and 3-prong power-plugs?

Besides, Macbook Pros are usually not properly grounded anyway. Once you connect them to an external display or other properly grounded device they will share the proper ground.

When you connect devices of different grounds you can get electrical sparks. The voltages and especially amperage are pretty low though (usually less than 10 volts). It can cause issues with active data-transfer over eSATA ExpressCards though (stalls or link losses, can also lead to Kernel Panics and system freezes).

Yikes. Thank you.

Yes, the prongs are mixed. Three pronged on the Mac, two prongs on both of the disk docks.

Is there anything I can do to stop it? i'd hate for it to cost me the data.

 

[Timur]

Don't attach new cables of mixed grounded devices during data transfer, like attaching an external display, powered USB hub (unpowered is ok) or powered audio interface.

Once devices are connected with each other they will share one common ground anyway. Only the plugging is problematic.

And be happy you are not using a 2008/09 Macbook Pro where data corruption even happened with nothing being touched at all (regardless of what ExpressCard you used). Apple never cared...

 

[iamjohnsname]

Apple don't seem to care about anything. I've had non-stop problems with this machine and when I ring Apple they basically just tell me to deal with it and see how it goes. I don't really understand where their dedicated fan base comes from.

 

[Timur]

Your changes are better at Apple Stores where you can put the broken thing right on their desk in front of other customers. Phone support is less than stellar for any complex issue.