Rcd not tripping when tested ?

[Engineer54]

See im baffled by the ze yes water and gas bond disconected Defo tt even got a note on the cut out dont supply PME ,16mm to 3/8 spike at source then a 16mm 3 core swa via a switch fuse to the DB, i never disconected outgoing neutrals on my rcd test at the unit its self , the testers only 3 months old but im hearing there are issues with the earth pins inside it's a robin MFT going to borrow a mates and see if thats the issue, but i just can't understand one working and the other not. Looking in the board im not 100% its not been adapted from a old 100amp 30/ma split load style and the busbars etc might not be right but it all seemed to be conected fine to me. A longer look maybe required apon my return i think.

An Ra of 0.70 ohms on a 3/8'' twig?? Not even in your wildest dreams!! lol!!!, Even the dammed cable is bigger than the spike it's attached too....

 

[huntos33]

An Ra of 0.70 ohms on a 3/8'' twig?? Not even in your wildest dreams!! lol!!!, Even the dammed cable is bigger than the spike it's attached too....

Telling you now ZE of 0.70 droping to around 0.63 on zs I'm curious as to why its so low but thats what im getting, im back next week with a another tester to double check readings

 

[huntos33]

just a quick update on this ,Been back today changed the bus bar and fitted 4 seprate rccbos got 3 out 4 curcuits passing the rcd and other relevent tests now just 1 ring to go now that trip for love nor money but ever other test is fine !

 

[Engineer54]

just a quick update on this ,Been back today changed the bus bar and fitted 4 seprate rccbos got 3 out 4 curcuits passing the rcd and other relevent tests now just 1 ring to go now that trip for love nor money but ever other test is fine !

And the outstanding Ra values on a 3/8th twig??

 

[Bobster]

And the outstanding Ra values on a 3/8th twig??

Its managed to make contact with the incoming gas/water pipe lol.

 

[huntos33]

Its managed to make contact with the incoming gas/water pipe lol.

It's hit something lol but thats what it is, used 2 diff testers supplys overhead so it not that

 

[richy3333]

As you have concerns over the wiring of the CU any chance of supplying a photo of the 'guts'?

 

[huntos33]

As you have concerns over the wiring of the CU any chance of supplying a photo of the 'guts'?

Ive changed the set up now with a main switch new busbar and 4 rccbos and then the 30ma rcd for the remaining curcuits just the one curcuit not tripping the rcds now

 

[SPARTYKUS]

Whereabouts in the country is the job, huntos33?

 

[Engineer54]

It's hit something lol but thats what it is, used 2 diff testers supplys overhead so it not that

I'd still have trouble believing a 0.63 Ra with a metre long 3/8 twig, even if driven into a salt marsh. Something just isn't right here!!!

 

[SPARTYKUS]

My gut feeling is still a parallel path to a TNCS Connected service of another premises, but as you say huntos33 all other paths disconnected when reading Ze. Nice and chewy