ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades GFCI's pops in large numbers

Got the responsibility for a 100 yrs old building, The elctric systerms was rewired at lo cost 15 yrs ago. When I com in the morning at least one, sometimes 15 FFCI had don their job... but all measuring shows nothing wrong.

We have a 230V 3 phase supply quite equal to US 208V delta systems. (I'm in Norway) All this is wired for 230V single phase.

All hints to find and make documented reports are welcome.

If you have access to a power line monitor it might be worth a look but I am not really sure what kind of transient would trip multiple GFCIs. I assume the building is empty at night and you don't have a cleaning lady walking around plugging in a bad vacuum cleaner until she finds one that works.

I do only have a regular multi-meter, no power line monitor. And yes the building is empty during the night :-) Nice weather, no lightning.

Any animals or insects around at night that could access wiring?

No, none that I have seen, or tracks after insects or animals. it is turning to be colder now, and I have to be extremely aware of rats and mice that would prefer to live indoors during the winter, but no signs so far.
Large green area close to the building, pretty moist ground there now after day of raining, but that's after the the faults.

Discovered and fixed an error where 2 small branches was interconnected! Horrible error probably made when the building was rewired 15 yrs ago. After solving that no more errors in that sub-panel. The electrician could not understand how an error like that could have been there for so long without being a greater problem. At least it has been there since I came there in April.

One thing I learned as an inspector is installers seldom make one mistake if they are making mistakes. It is worth inspecting each circuit you are having trouble with paying particular attention to the neutrals. Folks tend to get sloppy with them assuming they are grounded conductors, what could go wrong but if they get grounded or share current with another circuit on the load side of a GFCI/AFCI it will trip. You may find multiple problems once you start looking but you have to start somewhere..

Today I i made a ground fault extension cord...I did switch the live and ground, plugged in an old (double insulted, un-grounded so it should be safe to touch) drill an did some testing, and at least in 2 positions both the actual GFCI-breaker and one more did trip. Maybe induction, because it did not happen each time.

The reason are probably in another part of the building, and the combined breaker of the trade mark Chint, was renamed by one I do not know, but overheard calling it Shit. It may be right renaming, but I am not 100% sure. :-)

I do not believe so, but it may just be bad English from another Norwegian :-)

I'm pretty sure I have found the ground fault, a pretty large pump, when running another pump, the fault does not come back, but it is still bad that so many Chint breakers release because of an ground fault so far away. If someone asks I will never say "use that brand". Conclution: It is far to expensive to go for such lo-cost solutions!

dsk,
Are you really sure that that is the issue though?
Have you tested the actual earth leakage circuit breakers to rule them out?
What voltage and size pump motor is it that caused this fault to occur?
I find it very strange that a single motor could cause multiple RCD's to trip at any given time,
unless there is an issue with the neutral-earth link at the switch-board or some other poor
neutral connection somewhere in the system.
Anyone doing electrical work these days should have at the very least one of them either Fluke,
Kyoritsu or Megger multi-function testers, they give you so much in the way of things you can test.
My Kyoritsu tester allows me to upload to my laptop and it's instant test records.
I have insulation resistance to 1000V, Earth-Loop, Continuity, Earth Resistance (2P, 3P), RCD Tester.
You only have to buy it once.