building wiring fault

[John Frum]

My APC SurgeArrest power bar shows "building wiring fault" appears to be all outlets on one phase.
I have no idea how long this may have been going on as the power bar is usually fairly inaccessible.
I didn't test them all because some are a giant pitb(where b stands for back) to access.
No faults are detected on the opposite phase.
I also have an older model APC SurgeArrest personal and it doesn't show a fault on the same circuits that showed errors.
I have an outlet tester which shows correct wiring.
I checked with my dvom and the only thing of interest is ~1volt between neutral and ground which is consistent across both phases so probably unrelated.
Any ideas?
Any further tests?

I guess I better get an electrician on the case pdq.

 

[gnubie]

Do you see any DC between line / earth / neutral? That might be upsetting it.

1VAC across earth / neutral is interesting, but could just be indicative of drop across the neutral due to load. Imbalance in your loads between the two 110VAC circuits would cause neutral current and might explain it if there is enough. If you turn everything off, at the applicances end rather than your breaker panel, it should go away if that is the case.

*not a sparky, not familiar with USA split phase systems*

 

[John Frum]

Do you see any DC between line / earth / neutral? That might be upsetting it.

~20 mVDC between hot and neutral and hot and ground.

 

[gnubie]

Nothing to worry about then. Are all the outlets on one wiring run or is it different circuits back to different breakers? I'm wondering if the unit tests neutral / earth resistance and it's over spec but that'd be pretty advanced for a UPS to do.

 

[John Frum]

Nothing to worry about then. Are all the outlets on one wiring run or is it different circuits back to different breakers? I'm wondering if the unit tests neutral / earth resistance and it's over spec but that'd be pretty advanced for a UPS to do.

Problem occurs on all the fuses that I can test on one phase and no fuses on the other.
Its not a UPS its a surge protector power strip.

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[gnubie]

Ah, normally those things are just LEDs lighting with voltage where it shouldn't be. 1 VAC between earth and neutral could well be the explanation. All there has to be there is enough current to light the LED at the LED's voltage. Depending on the colour 1VAC peak would be enough. If you do get a sparky to investigate let us know what the finding was.

This is the concept, but with neons instead of leds

 

[John Frum]

I forgot to include this link https://www.apc.com/ca/en/faqs/FA158817/

 

[gnubie]

Just remembered, I had an APC powerboard randomly show a fault on my own wiring a while ago. Out of the blue one morning it lit up. Tests showed nothing wrong or out of spec but a look with my 'scope showed noise between neutral and earth. I don't know where it was coming from as it persisted with everything turned off and it went away by itself. If it wasn't early in the morning when it happened I would have checked with a neighbour to see if they saw any problems.

 

[gnubie]

I forgot to include this link https://www.apc.com/ca/en/faqs/FA158817/

Well I hope it's not that you have multiple circuits with active / neutral transposed. ?

 

[John Frum]

Well I hope it's not that you have multiple circuits with active / neutral transposed. ?

Checked with an outlet tester.
All present and correct.

 

[gnubie]

Is the tester a LED or a neon type? That might be a clue.

 

[John Frum]

Is the tester a LED or a neon type? That might be a clue.

I think it's led

 

[John Frum]

Electrician came by today.
Did a thorough check and said that its safe.
He can't say why my power strip is showing an error but things are safe.

This guy had 10 years on me at least.
I felt like a heal when he had to basically crawl under my kitchen countert to inspect the fuse box.

 

[gnubie]

I suspect it's just the power strip is a tad sensitive to the neutral earth voltage. If it is an LED type it takes bugger-all to light one. The older style neon testers were pretty much impossible to false indicate.