Funny business

[cliffed]

Call out to a job,flat with Db protected by 30ma trip as main switch.
Rcd had tripped but not in clients flat,main intake area downstairs.
There I found a 30ma rcd which supplied Db in upstairs flat.
Apparently this as been tripping on a regular basis,& got worst,obviously no discrimination between rcd s,& so,a nuisance.
Did all the correct testing,& installation proved ok,rcd tripping times ok too.
Major concern is that it's a tt system,& there are other rcds in situ,controlling various other supplies.
At main intake a 100 ma time delay rcd is installed,& sometimes this trips,& causes havoc to all.
The flat seems to cause all this once tripped,tried explaining to client the ins & outs,but goes way over the head.
I think I gonna do a runner.

 

[Toneyz]

Why is it a TT system ? what testing have you done so far.
alot of the time RCD/RCBO's don't trip is that they stick as not tested quarterly

 

[Wilko]

Sounds like a new design for the installation is needed, which could be an opportunity. As I read it, there must be a fault somewhere that's setting off the RCDs but it might be tougher than usual to find. If you do carry on with it - perhaps IR test circuits with external lights - I've had a couple of these go bad recently with the seasonal damp (and diy ... ).

 

[cliffed]

Why is it a TT system ? what testing have you done so far.
alot of the time RCD/RCBO's don't trip is that they stick as not tested quarterly

No Earth provided by Rec,insulation tests between conductors all fine,times are ok.

 

[cliffed]

Sounds like a new design for the installation is needed, which could be an opportunity. As I read it, there must be a fault somewhere that's setting off the RCDs but it might be tougher than usual to find. If you do carry on with it - perhaps IR test circuits with external lights - I've had a couple of these go bad recently with the seasonal damp (and diy ... ).

Cheers exactly what I think,its like your an electrician it's gotta be fixed now !!
This all happened late afternoon today,so most probably go back soon,or someone else's headache.
,cheers,happy new year.

 

[Toneyz]

I think exactly what Wilko has put above to also if there is a leakage to earth from each flat and landlords but not enough to trip 30mA but together trips 100mA how old is the installation.I would see if supply could be upgraded to PME etc if a earth is provided to the buildings nearby gives a good indication.