RCD trips another RCD

[AB1977]

Why would one RCD trip the other RCD when I turn on a power circuit MCB?

 

[Sharpend]

How long has this been happening?

what works have been done prior to it happening? 

 

[binky]

borrowed neutral gets my vote

 

[Murdoch]

Neutral in wrong bar ?

 

[SPECIAL LOCATION]

Why would one RCD trip the other RCD when I turn on a power circuit MCB?

Yes if they are wired incorrectly.

 

[kerching]

As previously said.......I would say that somebody has been doing some alterations /additions and has got the neutral wrong.

but what do I know

 

[sprocketflup]

Cant believe no-ones mentioned that it might be the neutral yet