Site Wiring Fault Exists Message

[BillP]

I have an interesting situation.

I have two Smart-UPS SMT750RM2U UPSs with AP9630 management cards (with current firmware).  They are both plugged in to the exact same outlet and that outlet is the only thing on that electrical circuit.  The one UPS is a month old and is working perfectly.  The second UPS is about three years old and keeps send me notices once or twice a day that there is a site wiring fault that lasts for two seconds.

The battery finally needed to be replaced on the UPS with the wiring faults.  So instead of just changing the battery I replaced the whole unit keeping the same management card.  However I am still getting the wiring messages.  I have also tried swapping both UPS's power cords in the same outlet.  Both pass their self tests and calibrations.

I am at a loss.  Could it be the management card?  I have not swapped them yet.  Or could it be the equipment connected to the UPS?  What would be the next thing to look at?

[BillP · Accepted solution]

swap the NMC's over and see if the fault follows it to rule out the connected equipment or the card