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No, it is a perfectly safe way to do it.Thanks, but i am not sure if that is a safe way to do it...
No, you can do this test with the PSU disconnected from the mains.because obviously the PSU has to be plugged in and ON......
No, whatever gives you that idea?and that means that if it is an isolated PSU, then it may have floated up to a very very high voltage, and i thus may blow up the Ohm Meter?
No, totally erroneous assumptions..having said that, if the ohm meter DOES blow up.....then we definetely know that it must have been an isolated power supply?
No it does not.OK thanks, .by the way, the KERT KAT5VD has a 2 pin mains plug. ...........so that means that it can't possibly have an output connected to earth ground....or does it?.........
Yes, usually.isnt mains neutral connected to earth ground in the vicinity of the installation/building.
No, I hope not!................so wouldnt the output common be connected to input neutral?
Quite right!This is quite something, i am always being told not to cut off the earth connection from a three pin plug
Nonsense!...........well hold on.........all European mains products are 2 pin, so they have exactly that, a plug with no earth connection
I guess you have no idea why there is an earth connection there......so why am i always being told (eg told by eng-tips forum members) that cutting the earth wire of a plug is a bad thing?
Some European plugs are two pin, but there are lots of three pin ones, like the Shuko on that Italian PSU.
OK thanks, .by the way, the KERT KAT5VD has a 2 pin mains plug............so that means that it can't possibly have an output connected to earth ground....or does it?.........isnt mains neutral connected to earth ground in the vicinity of the installation/building.................so wouldnt the output common be connected to input neutral?
This is quite something, i am always being told not to cut off the earth connection from a three pin plug...........well hold on.........all European mains products are 2 pin, so they have exactly that, a plug with no earth connection.....so why am i always being told (eg told by eng-tips forum members) that cutting the earth wire of a plug is a bad thing?
it could raise the case of the devices to about 1/2 way of the line voltage
Isolating the device under test, isolate the instruments
it could raise the case of the devices to about 1/2 way of the line voltage
Suppose that ground isn't connected to earth, but to another instrument?
You want to work on a 100 kV 0.1 A or a 12 kV 1.5 Amp power supply with the third prong snipped? I don't and won't
the OP said:I dont see how that could get connected to another instrument?...its inside the product case..how can it get connected to something else?
I think all those reasons were already mentioned: 60 or 120VAC on case(s), EMC compatibility.. For example, if you have a 5-socket cord with cut-off ground and have in there 5 devices with EMI filters, 2x4.7nF Y-caps each, you can get about 1mA fault current through your body. That doesn´t look very healthy, especially with nice path to ground through other hand.I have still yet to hear of a good reason for not doing plug earth snipping on scopes.
Even in the biggest, largest, most prestigious corporations, universities and organizations, there will be arrogant individuals which make stupid decisions.
..................i've never seen a scope with a metal case........they all have plastic cases60 or 120VAC on case(s),