"Dave Plowman (News)" wrote in message
...
In article ,
dennis@home wrote:

"Dave Plowman (News)" wrote in message
...
In article , Clive Mitchell
wrote:
So you have equipment with floating mains earths and you have
earthed equipment. A fault occurs, someone bridges the two pieces
of equipment and gets killed.

No - it earths via the screen on the connecting cable.

Which is nor rated to carry mains fault current.

Depends on the value of the appliance fuse - not the plug one. Good
quality co-ax will have a screen cross sectional area at least the
equal of 0.5mm mains cable.


However it may not be earthed. The screen needs to have a low impedence
to earth for ac signals and not for mains/DC. It could be coupled using
a capacitor and hence offer no protection at all.

In which case it won't cause an earth loop so there'd be no need to remove
the mains one.

There's a hole in my bucket, dear Lisa, dear Lisa...

But you removed the earth last week when you had a different device
connected that did create an earth loop.

You can get a new bucket for 99p in B&Q if you can't find any straw.