RCD trips on incoming power dips

[damartin]

Property suffers from high number of voltage anomalies - all traced back to high voltage faults by EDF. Problem is that the RCD (80A 30ma) trips on most of these. Mega gives 2M across the circuit. RCD has been replaced as a precaution but same issue. What could the possible problem be? - have others had this issue? Should I be looking into time delayed RCD as a replacement or is this clearly some device fault within the property? Any advice would be welcome because I have been pulling my hair out over this one. Trips do not happen with enough regularity to remove devices from the sockets to rule equipment in or out - sometimes there will be 3 trips a week - then nothing for months.

 

[Darkwood]

What are you insulation testing when it reads 2meg, how do you know you are getting transients from the energy supplier, tell customer to note time and date and what they think was powered when it tripped and also what the weather was to see if was wind or rain creating a problem.

 

[damartin]

Thanks so much for your reply. 2M between live and earth across circuit with all devices plugged in. As for energy supplier - it was noted that lights would often dim or flicker around trips - so EDF agreed to fit supply logger for a week - in this time there were two trips - both times the logger confirmed anomolies which EDF matched with high voltage issues that would affect local substation. Outages occur in all weather conditions - have not yet been able to find a patern - all seasons all times of day - most common if anything early in the morning.

 

[martspark]

is it a front end RCD for the whole installation - if it is you cant
replace with S type

if it aint can you temp fit rcbo in place of mcb on skt circuits if you
you think thats where problem is?

cud be combined devices providing earth leakage enough to get close
to 30mA

You do the megger test with devices still plugged in?

 

[Darkwood]

With a confirmed supply transient issue it could cause havoc with appliances etc as well as nuisence tripping, firstly id fit a mains filter at the front end to protect the installation and secondly id do individual insulation tests to each circuit so as to narrow this low reading down.
It may be that the area is prone to lightning strike to pylons which could be many miles away so going unnoticed by customer it may just be coincidence with all the recent storms though.