RCD tripping

[jimmyfield3877]

Hi All, I'm having an issue with an RCD tripping. I've run 6mm Hi Tuff from house to garage CU, run is no more than 10 metres. This has a 40A RCD with a 32 and 6A breaker in. Zs, R1, R2, insulation resistance readings etc are all good for the cable. The problem is as soon as I turn the Garage RCD on it trips straight away and also trips the breaker in the house at the same time. I've checked the connections, they are all secure, no cables touching anywhere they shouldn't. The 32 and 6A breakers I disconnected from the circuit so only thing drawing current is the 6mm. I just cant see what the issue is, anyone have any ideas will be greatly appreciated. Thank you.

 

[telectrix]

neutral in wrong bar at the house CU.???

 

[westward10]

When you say breaker in the house is this just an mcb.

 

[buzzlightyear]

post a pic up inside the cu.

 

[radiohead]

If as you say and I understand it...... the cable tests are satisfactory, and the cable can be energised without tripping the supply end, and nothing is connected to the load side of the garage RCD....Then the only logical explanation is that the garage RCD is faulty tripping itself and the supply end when switched on.
Unless the above is not the case and you have missed something in your initial verification checks.

 

[westward10]

Any chance of more info?