rcd tripping on a ring main

[Daveh36]

Ok help before a pull out the rest of my hair got an rcd that trips when ring main breaker turned on got continuity but still trips when only live connected ant ideas

 

[Pete999]

If this is a dual rcd board and I know this is obvious but are the neutrals definitely in the correct neutral bar.

For some reason the OP seems to be saying no Ns connected.

 

[littlespark]

Does the rcd stay on with no lives connected either?
Rule out a faulty rcd

 

[Pete999]

If this is a dual rcd board and I know this is obvious but are the neutrals definitely in the correct neutral bar.

For some reason the OP seems to be saying no Ns connected.

 

[Deleted account]

For some reason the OP seems to be saying no Ns connected.

I'm a bit confused myself on this one. Don't understand the situation.
Better explanations is needed I think.

 

[Midwest]

OP is saying he has only lives connected, energises mcb & then RCD trips. That 'lecky is going somewhere, and as already suggested there must be a parallel path to earth. Even 16 MΩ sounds like there's an issue somewhere, connected load or earth fault.

 

[Andy-1960]

Are just the neutrals for this circuit disconnected or all the neutrals in the board? I’m thinking borrowed neutral maybe?

 

[nunthe wiser]

Most likely circuit across 2 rcds

 

[Midwest]

Back to the beginning again, testing wise.

 

[SparkyAndGeorge]

What board have you installed put a picture on here

 

[ChrisElectrical88]

What was it in the end?

 

[Risteard]

ok so got continuity not shorts insulation resistance low but not too low at 16meg and again all I have connected or two lives of the ring no neutrals for any circuit no earths for any circuit. RCD stays on until I turn the breaker on. Never come across a fault like it

Why would you energise without cpcs connected (let alone neutrals)?

This is not a safe way of fault finding.

 

[The_apprentice2.0]

why have you disconnected the neutrals? RCD's compare the current between line and neutral so if you do not have the neutrals connected the RCD will not reset???

 

[Pete999]

why have you disconnected the neutrals? RCD's compare the current between line and neutral so if you do not have the neutrals connected the RCD will not reset???

Mentioned something similar in post 13.

 

[jackhammerJIM]

why have you disconnected the neutrals? RCD's compare the current between line and neutral so if you do not have the neutrals connected the RCD will not reset???

With the neutral disconnected how can current flow ?

 

[Midwest]

Through an earth path.