When I have seen this, there has been a wiring problem, usually a bad ground. Sometimes also bad stuff like tingling when you touch the electrical boxes. Telling the site owner to get an electrician in to fix the wiring has always resolved the problem. That would be my first approach, it is a serious problem with the electrical wiring that needs to be fixed. Otherwise, there is a safety issue. Not just for your equipment, but for personnel.
You could have a unique situation if this is a farm, grain elevator, etc. with long runs to the ground and neutral, transformers converting from 480 3-phase, etc. Worst case you could put in a 1:1 isolation transformer and your own ground, but first choice is to get the wiring fixed. From: Af [mailto:af-boun...@afmug.com] On Behalf Of Chuck McCown Sent: Thursday, February 16, 2017 10:38 AM To: af@afmug.com Subject: Re: [AFMUG] APC Site Wiring Fault But they run back to two different bars. The neutral bar and the ground bar. Then normally those two are bonded and the ground bar goes to the building entrance ground rod. Any bad connection coupled with decent amount of current causes voltage differences. From: That One Guy /sarcasm Sent: Thursday, February 16, 2017 9:35 AM To: af@afmug.com <mailto:af@afmug.com> Subject: Re: [AFMUG] APC Site Wiring Fault I never understood how there can be a difference between the two in most of our scenarios we are on a dedicated breaker. the ground and neutral terminate to the same place usually on 12/2wg or 10/2wg and the only thing on the circuit is our APC. the insulated neutral and the copper ground are the same wire in romex arent they? just one has insulation? On Thu, Feb 16, 2017 at 10:19 AM, Nate Burke <n...@blastcomm.com <mailto:n...@blastcomm.com> > wrote: I think I read the error occurs if there is >5v difference between neutral and ground. The Strange thing is that it's happening at the same time every day. On 2/16/2017 10:13 AM, That One Guy /sarcasm wrote: good luck. APC has a little guide for troubleshooting them, but never much detail. we have a couple sites that always have it, never had any impact. I suspect its overloaded ground. Maybe the smart meter shunts voltage to ground for some safety verification or something like that, or more likely to identify utility theft since all those smart meters are about is profit On Thu, Feb 16, 2017 at 10:08 AM, Nate Burke <n...@blastcomm.com <mailto:n...@blastcomm.com> > wrote: I have a UPS that I recently installed pulling a 'Site Wiring Fault' for 20 seconds a few times a day, at the exact same time daily. There are no other local electrical device at the location that I can find turning on or off at the same time, or that would have this kind of regularity. There is a smart meter at the location, could the smart meter be doing some polling that would cause this? I have another Identical UPS off the same utility HV line, but different transformer and meter, and it does not have any errors. Has anyone seen these before and been able to track down a cause? On the APC forums, one reply was to simply disable the alert, saying otherwise you'll descend down a never ending rabbit hole of diagnosing and tweaking your electrical plant. Nate -- If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team. -- If you only see yourself as part of the team but you don't see your team as part of yourself you have already failed as part of the team.
