It weren't broke until I got there an' improved it.

[Marti]

So...
This is all on my house and no animals were harmed in the making of this hash up but the Mrs doesn't know...yet.
A few years ago we had this house rewired. Usual story, a lash up by an unqualified because we knew no better and it was one of the incentives for me to qualify and offer a better service.
The CCU is an amendment 3, 16 way, split board rats nest but I've completed an EICR, resolved the issues and all was well. Trouble was I hated the rats nest and gave an afternoon to stripping it out, labelling, making sure the L and N were each in the correct side of the board, all tidy and collecting my gold star.

I have a garage CCU running via 40a type C via SWA to my workshop. One RFC and a light via an RCD.

NOW if I plug in any device in the workshop the 40a type C (at the house) trips with the relevant RCD. IR, polarity and RCD all test fine at the workshop so I've buggered something at the house end. Does this mean I should have been a plumber / pimp / Trump supporter?

Apologies for the long story. I have humour where my dignity should be. What are your thoughts on the problem

 

[buzzlightyear]

I have a garage CCU running via 40a type C via SWA to my workshop. One RFC and a light via an RCD.

NOW if I plug in any device in the workshop the 40a type C (at the house) trips with the relevant RCD. IR, polarity and RCD all test fine at the workshop so I've buggered something at the house end. Does this mean I should have been a plumber / pimp / Trump supporter?

two rcd in series not good .

 

[telectrix]

fault is probably N in wrong bar. if it trips only when yo apply a load.

 

[Pete999]

So...
This is all on my house and no animals were harmed in the making of this hash up but the Mrs doesn't know...yet.
A few years ago we had this house rewired. Usual story, a lash up by an unqualified because we knew no better and it was one of the incentives for me to qualify and offer a better service.
The CCU is an amendment 3, 16 way, split board rats nest but I've completed an EICR, resolved the issues and all was well. Trouble was I hated the rats nest and gave an afternoon to stripping it out, labelling, making sure the L and N were each in the correct side of the board, all tidy and collecting my gold star.

I have a garage CCU running via 40a type C via SWA to my workshop. One RFC and a light via an RCD.

NOW if I plug in any device in the workshop the 40a type C (at the house) trips with the relevant RCD. IR, polarity and RCD all test fine at the workshop so I've buggered something at the house end. Does this mean I should have been a plumber / pimp / Trump supporter?

Apologies for the long story. I have humour where my dignity should be. What are your thoughts on the problem

Have you taken the feed for the W/Shop from an MCB and taken the N from the wrong N busbar? without being there it's very difficult to trace any faults, maybe a borrowed N causing your problems, either that or you have screwed up the connections at the W/S CU.

 

[SparkyChick]

Some pictures of the inside of both boards may help.

But just to clarify... both the 40A type C MCB AND the RCD supplying it trip, correct?

 

[MJPD29]

Probably neutral connected to wrong bar in house board

 

[Yozza19]

Or earth neutral reverse on swa

 

[Nebu1a]

I dont know about a rats nest but I once found a mouse welded to the incoming main switch terminals of a detached garage CU.

 

[Marti]

Thanks Guys,

My bet, from what you've said, is that I've got the neutral in the wrong bar. Haven't had time to check but I'm confident that, from the SWA onward is fine. Funny enough, this was the situation that prompted me to asked about labelling in another thread.

 

[Marti]

I once found a mouse welded to the incoming main switch terminals of a detached garage CU.

He had it in-comin'

OH, Buzz Lightyear, point noted about series RCD's. I will correct that as well - thank you

 

[buzzlightyear]

Jigsaw Electrical Services ,you can put togather .i have piece missing .

 

[Marti]

But just to clarify... both the 40A type C MCB AND the RCD supplying it trip, correct?

That correct SC. the fact that this was working perfectly until I fixed it suggested the issue is at the house end where I tidied up the wiring but double checking all the workshop installation did seem good practise.

 

[Nebu1a]

"making sure the L and N were each in the correct side of the board, all tidy and collecting my gold star."

Might have to give the gold star back

 

[SparkyChick]

That correct SC. the fact that this was working perfectly until I fixed it suggested the issue is at the house end where I tidied up the wiring but double checking all the workshop installation did seem good practise.

Does the same occur if you turn the lights on in the workshop?

 

[Bobster]

If the MCB is tripping as well as the RCD, then it is likely not just putting the neutral in the wrong bar.

That wouldn't have any effect on the MCB.

Start by doing an IR test on the circuit.