RCD Tripping

[Danny_Labrador]

So the garage is without an electrical supply, so I decided to install one.

I laid about 20M of 2 core 2.5mm2 armoured cable and terminated it in the garage with a consumer unit.

Added a metal clad double socket again supplied by 2.5mm2 - all mounted on a large sturdy wood board and encased in trunking.

Ran separate trunking with 1.5mm2 to a strip LED light in the centre on the ceiling with a pull switch.

I tested the installation initially with meter and then live with an extension in the house run to a 13amp socket and it all worked perfectly.

I finally wired it into the main fuse box but now it immediately trips the RCD.

OK the obvious conclusion is that somewhere I have a leakage of current to earth BUT the aforementioned socket is wired through the main distribution board through the RCD. I have checked that the MCB supplying the socket is protected by the RCD - it is.

So the RCD does trip when it's supplying current through the socket outlet bit does trip when it supplies current through a new MCB.

Curious.

Any technical solutions please.

 

[SJD]

Is the N connection in house in the correct N busbar?

 

[buzzlightyear]

have checked the screws on the metal box might be on the tails touching the conductor ..

 

[goasis]

You say you tested the install with a meter, what results did you get?
Also how are you providing an earth to the garage?

 

[MJPD29]

Interesting what test results did you get? Also, put up a pic of consumer unit may have mixed neutrals up

 

[radiohead]

As above, it sounds likely that you have incorrectly terminated the N in the house DB. Bear in mind this installation requires notification to BC, if you fail to do so and have not installed and tested it in accordance with Bs7671 you are breaking the law.

 

[Baddegg]

As above, wrong neutral bar?....what test results did you get?.....you say using 2 core swa what are you using as the earth....the armour or have you TT’d?....

 

[Danny_Labrador]

Neutral in the wrong busbar - silly mistake - thanks to all those who spotted it and posted.

 

[telectrix]

well done for owning up. bet there's a lot more members wot have done that at some time, but won't admit to it. i know i did it once and had a shower replaced before i spotted it. to be fair though, there weren't enough N terminals on the correct bar.