multiple RCD's tripping throughout the building

[srewolf21]

One of the buildings we maintain has had a problem on and off for a number of years now with multiple RCD's tripping simultaneously on different fuse board's across all three phases throughout the building. I have literally stood watching the fuse board's within the electrical intake and have seen up to 12 RCBO's going out almost the same time.
We have carried out periodic inspections even down to using high current meters to check the integrity of the main neutral, earths and bonding.
I have recently become aware of harmonics within the electrical systems and was wondering as this can increase the current within the neutral within a 3 phase system if this could possibly be our problem.

My initial thoughts on what was causing this was a external neutral problem from the supply side as it is a PME system.

Has anybody else got any other ideas?

 

[Knobhead]

Do you have access to a power quality meter? It may give you some idea of what’s happening with the neutral.
But to be honest it shouldn’t cause problems with a RCBO but with the modern electronics in them it’s anyone’s guess.

 

[ringer]

I was talking with a guy at the Cov Elex who is having problems with rcbos tripping when they are using walkie-talkies next to the board. Not sure if that is what is happening in your situation but is evidence that rcbos are susceptible to external electronic noise.

 

[Knobhead]

It’s ironic, we want higher standards of protection, but that method of protection is fallible.
So we now have unreliable protection, where do we go from here?

 

[telectrix]

It’s ironic, we want higher standards of protection, but that method of protection is fallible.
So we now have unreliable protection, where do we go from here?

just have to look forward to pension day, mate. time to let the younger ones sort out the mess.

 

[Inteificio]

wait, why did I 'like' that, I am one of the younger ones!!!

 

[srewolf21]

I was talking with a guy at the Cov Elex who is having problems with rcbos tripping when they are using walky-rallies next to the board. Not sure if that is what is happening in your situation but is evidence that rcbos are susceptible to external electronic noise.

I have come across that problem before but it was with older mobile phones causing MCB's to trip. in this case I do not think it is the problem however with RCD's and RCBO's anything is possible.

 

[srewolf21]

Do you have access to a power quality meter? It may give you some idea of what’s happening with the neutral.
But to be honest it shouldn’t cause problems with a RCBO but with the modern electronics in them it’s anyone’s guess.

as I work for a small company we do not have a power quality meter and would have to hire one the main reason I'm floating the idea of the harmonics is I have only recently become aware of this problem (and I really hate finding out about something I know nothing at all about) and as they seem to increase the neutral currents especially within three-phase systems was wondering if this could be a potential problem with RCD'S.

 

[Kamikaze]

wait, why did I 'like' that, I am one of the younger ones!!!

Hang on in there mate, retirement is only 40 years away...lol

 

[srewolf21]

It’s ironic, we want higher standards of protection, but that method of protection is fallible.
So we now have unreliable protection, where do we go from here?

the regs go on about discrimination within electrical systems but it is becoming more and more difficult to provide it.

 

[Kamikaze]

As strange as that might seem it could be earth leakage from outside the system coming in.

 

[srewolf21]

As strange as that might seem it could be earth leakage from outside the system coming in.

I think this is the strongest possibility and was my initial thought especially as historically the fault seemed to get worse with poor weather conditions we are still waiting for EDF to carry out a fritter test. But at the moment I'm open to any ideas.