Ground circuit integrity testing

[brascot]

Can anyone advise me of how to non disruptively test the quality and integrity of a ground line in a large building with multiple outlets. I am having issues with oddball transient glitches in computer equipment. This issue comes and goes in intemittent random bursts of activity at all times of day, night, week and seasons. I have ruled out mains borne RFI and ESD. I am wondering if I have a floating ground issue.

 

[dpc]

You can measure current flowing in a ground wire using a clamp-on ammeter with no disruption in the system. The green ground wire should have little or no current flowing.

But it seems doubtful that grounding or the lack thereof on a power circuit is causing the problems you are describing.

Have you ruled out power line transients such as voltage dips and sags? Also, what about directly radiated RFI from handheld transceiver, wireless transmitter, cell phones?

 

[brascot]

Thanks for the response. I know the theory about a possible floating ground is flaky, but I'm scratching my head on this. I have had power analysers on the line and showed no correllation between the freaky events and any conducted HF noise, sags or spikes. I must admit, I never gave radiated emmissions a thought. I'll give that a shot and see what happens. I am open to the fact that the subject equipment might be a bit sensitive to something environmental in nature, and I have someone doing a pretty detailed analysis from a buss monitor trace I just had collected. Cell phone interference is a possibility I can examine easilly. Thanks very much for your help.

 

[dpc]

If you have someone with a handheld "walkie-talkie", such as a security guard or similar - these can deliver a hefty RF punch to consumer-grade electronics gear. Cell phones can cause problems also, but they generally operate at a much lower power output. My cell phone gets all over my computer sound system when it rings.

If you are running low level serial or Ethernet cables between buildings, then the signal grounding at each end can be a problem. RS-232 serial assumes a common ground potential at each end. This makes long serial cable runs very problematic.

A portable AM radio makes a good broadband RF detector.

Good luck.

 

[mohanlal]

You connect a test lamp preferably 230/110V depending on your supply voltage and connect between phase and ground terminal in the extension plug points and confirm the lamp is bright similar to connection bet phase and neutral. Thsi is one of the grounding integerity test I would recommend in a large building.
Also check the voltage bet neutral and ground at various places and it should be minimum say less than 5Volts if the grounding is proper.
Subramanian