Besides short circuit surge currents flowing on safety ground wire there are also other situations where you can see 60-115 V AC between the equipment cases. In the age of switch mode power supplies the safety ground has a new job, ie EMC line filter ground. When the power supply EMC filter is not connected to electrical ground, the the line filter y-capacitor often ends up connected to the output ground putting the output at half the line voltage that is 60V or 115v depending the country you live in. The low capaciance of y-capacitor limits the available current to some low value (fraction of milliampere normally but can be up to few milliamperes), so the system is kind of hi-Z output. If the unit powered by this ps has no other ground, balanced IO requires common mode mode rejection that that can handle 60V or 115v rms voltage. The techniques that can do this are rare, this is far more than normal op-amps or RS-422/485 drivers can handle. Beware “universal” switch mode adapters!
auto gatschnig
The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts
wadon998811
Good afternoon friends
Just want to say thanks, for your help and all information. Here I can find all information I need! 
.
I am from Republic and also now am reading in English, give true I wrote the following sentence: “After an eight nature end, donald suffered to the melancholia to upset margaret after she moved him about frank’s friends.”
Thank
Juro.
The Trackstick may be a useful solution
Absolutamente con Ud es conforme. Me parece esto la idea excelente. Soy conforme con Ud.
hey this blog is great. I’m glad I came by this blog. Maybe I can contribute in the near future. PM ME on Yahoo AmandaLovesYou702 Thank you day546
It´s lovely to surf with Google. Wrote electrical safety equipment and look what a great blog I´ve found