RCD tripping on off peak board

[TJC1]

We recently rewired a property, which had off peak storage heaters also with a 24hr supply for instant heat off the ringmain, as wired before. We didnt have to rewire the off peak storage heaters, only replace the fuseboard.
When we reconnected the main 10mm cpc bond the earthing terminal, everytime you switch the ringmain mcb on the rcd main switch of the off peak board tripped out!!
Very strange
We think we have narrowed it down to a pos faulty heater in the bedroom, but i cant see why the 10mm bond would effect the rcd tripping! Which is off peak so shouldnt have potential to trip out in the day??

Mabye the 24hr supply is some how back feeding to the off peak supply!?

Any ideas?

Many thanks

 

[guest119]

First post, so, hello there and welcome.

Boydy

 

[Plonker 3]

What are you Ze readings on both supplies?
IR results?

 

[Darkwood]

Following on - test results - what routine methods of fault diagnosis did you try and what conclusions did you come up with ..... from your OP- opening post you seem to have been posed a problem and not done standard basic diagnosis either due to inexperience or out of depth.

More details please on your testing etc ... if you haven't done any post this in the DIY section please!

 

[telectrix]

have you got a shared neutral between the 2 boards?

 

[Octopus]

So many questions, so little detail from the OP... time to get your tester out!