BN1500M2 wiring fault LED dimly lit

[rpbcv]

I have a BN1500M2 UPS and have noticed that the wiring fault LED is always dimly lit no matter which outlet I plug it into. I've confirmed with an outlet tester and multimeter that my outlet wiring is correct and no significant voltage is coming through the neutral wire. I would hope that a true wiring fault would light the LED in an obvious way, so is the dim LED normal behavior or do I have a faulty UPS?

[Teken]

The building (Site) wiring fault (SWF) indicator should never be lit. You can validate if there’s a problem with your specific hardware by installing it at a completely different location such as work / family.

If the SWF indicator is not lit at those new locations that indicates a problem inside the building of your home. 

Obviously, if the SWF indicator displays the same problem behaviour there’s a high likelihood this is a hardware issue. ☝️

If we assume the SWF indicator is valid and true these are some things to consider:

Ground: The single point earth ground must be less than <25 Ohms that bonds to the home’s electrical system.

Do not use 3-2 plug that omits the ground plug. Do not use extension cords to extend the input power to the UPS. A loose ground at the outlet / panel are common problems. If the home is extremely old validate there are no bootleg grounds present.

They are typically used to fool inspectors where a GFCI is installed! 🤢 You can perform a simple test to see if the ground resistance is greater than 25 Ohms. Wet the entire outside area where the ground rod connects to the service meter. If the SWF LED goes out you have your answer.

Neutral: Anything greater than (>5) VAC on the line will cause the SWF to light up and fault as it believes it’s over loaded. Simple test is to turn off all breakers in the panel except to the target outlet. If the SWF LED goes out you know there’s something bleeding voltage on the neutral. Turn on one breaker at a time to see when the SWF LED comes on / off.

Reverse Polarity: The hot / neutral are reversed at the outlet or breaker panel. Every outlet / switch must be inspected and at the service (breaker) panel to validate it’s state.

Isolators / UPS / Generators:

If this unit is connected to any sort of isolator / power conditioning device this will cause a SWF. If the unit is connected to another UPS as a means of extending the others operational runtime this too will cause a SWF if and when the UPS goes into AVR / Battery Only Mode.

Other devices such as an isolator provide a floating ground / no ground / tech ground. If these devices are present disconnect them to validate if they are the root cause. ☝️

If you have more questions please do ask. If not and this reply offered you a solution please do mark it as so. So it may help the next person asking the same. 👍

NOTE: Any plug that is easily removed from an outlet is a prime candidate for the SWF indicator due to poor ground pin contact. Other causes is due to corrosion inside of the outlet. 

Simple test clean the UPS plug and apply some dielectric grease. If after doing the above and the SWF LED goes out. Replace the outlet for a new one.