Rcd trips before I even switch on MCBs

[oldstudent]

Hi all

I've just fitted a new consumer unit. 10 way twin RCD.

After a very long day struggling in a tight location I powered up.

Switched on RCD furthest from isolator, held in OK, switched on mcbs protected by that RCD all OK

Switched on RCD next to isolator wont stay in. Even with no mcbs switched on.

Thought it may be a faulty RCD so swapped them over, same problem.

With no mcbs switched on either side, Rcd still wont hold in next to isolator.

I'm too tired to carry on now, can anyone give me some suggestions where to start checking in the morning.

Pre instalation tests were all fine

TNS system.

Only thing I had to do was extend some cables within the enclosure using crimps.

Thanks

 

[Amp David]

Double check to see if the flying lead for that RCD are correctly connected.

 

[Dunc]

Neutral to earth fault or you've got a neutral in the wrong terminal strip.

 

[tony mc]

Neutral to earth fault if its tripping before you switch on the MCB.

As you energise the RCD it is seeing a fault so if MCB's are all off the imbalance will be the neutral.

You have got the neutral connected to the neutal of that RCD??

Or a faulty RCD.

If your sure your IR tests are good try swapping RCD over then take it from there.

 

[topquark]

Neutral to earth fault or you've got a neutral in the wrong terminal strip.

Yep neutral in the wrong terminal strip would have been my guess.

 

[truckster]

Or a loose connection on that RCD. Is the neutral tight in the strip?

 

[Goody]

Yep neutral in the wrong terminal strip would have been my guess.

I second that.

 

[electromonkey]

I second that.

I third that.

 

[kev123]

I would fourth that, check your neutral connections within the consumer unit. This reminds me of when i was an apprentice mid 90's when certain manufacturers had you make there boards up. And we used to get the connections mixed up. ( flexible neutrals )

 

[telectrix]

yep. could even be a manufacturers tails incorrectly wired. donb't hink it#sa borrowed neutral as that would usually show up when a load is applied.

 

[Deleted member 9648]

Wish I had a quid for every time this comes up on here.....

(easy peasy a cu change,....anyone can do that cant they?)

 

[nickblake]

think its time to start fault finding and the easiest way to start is to disconnect each circuit one but one and testing them till you find the circuit thats causing the fault , you could have the good old can of worms here , easiest way is to disconnect the neutral of each circuit and try and switch on the RCD do this till it stops tripping , did you carry out any test whilst changing the board as you should have done as this would have highlighted the problem befor you energised

 

[ezzzekiel]

neutral earth fault - usual suspect outside light with water ingress

 

[DurhamSparky]

N-E usual suspect incompetence to fault find....! rather spend 10 mins logging on to forums to ask questions

 

[hasel5]

N-E usual suspect incompetence to fault find....! rather spend 10 mins logging on to forums to ask questions

My views exactly