Floating Circuit Design!!!

[bt9]

Would it be possible to design a circuit that would trip (i.e. relay, loud speaker etc.) if the return reference/path to ground becomes floating?! If it is or might be possible, any suggested reading material is greatly appreciated :-?

Thank You

 

[dick_freebird]

With some sort of remote sense, it ought to be simple enough to
detect that GND_remote <> GND_prime. The important question is,
do you have or can you add such connectivity?

 

[bt9]

Thanks for your response. remote sense is a good idea but I was thinking of something more simple. Let's say I have this piece of equipment that I want to be always referenced to edison ground. I want to know if there is anyway I could be alarmed if it gets unplugged or a cheater plug is used...

 

[crutschow]

Inject a small current (say 1mA) through a resistor from the neutral to ground. Monitor the voltage between the ground and neutral. If the voltages are significantly different then you are missing the ground. You can use a comparator to turn on a lamp when the voltage is too high.

 

[neddie]

I'm not sure what you mean by "Edison ground" , earth?
How about connecting a relay between + and - , with monitoring circuit on the contacts. Cut " - " and relay's contacts change.