RCD refuses to switch on (up)

[John Chalmers]

I’ve run a 2.5mm t&e cable from a 16a cu in the house to the shed all in 20mm plastic conduit - say 7m. The shed has a BG garage unit with RCD and two ways, 5 and 16a.
In the shed is a final ring circuit with a spur for a fan and a LED style fluorescent fitting. The RCD refuses to switch on. Even with both ways switched off the RCD will not switch on.
I have checked all connections and can find nothing. I checked the mcb, previously used for an immersion heater, by connecting the lights wire into it and everything was okay.
Wired brown into mcb, blue to neutral bar and earth to earth bar all on the non-elcb side of a MEM cu. Other end as per instructions into RCD.
Any ideas please? I simply wanted this up and working before bringing a sparky in to test and certify.

 

[Pete999]

ELHNC 404. By MEM.

Then the CU in your shed is covered by the ELCB in the house, is that correct?

 

[casperLennon]

What’s the box to the right of the cu?

 

[Pete999]

ELHNC 404. By MEM.

John can you post a pic of the house CU internals please?

 

[suffolkspark]

It looks like youve mixed up the neutral of the incoming cable with the other one next to it... Hard to see behind that blue neutral link

 

[Pete999]

I'm beginning to think the N is connected to the wrong busbar in the house, I'm confused with the OPs description of how it is wired I have asked if he can post a pic of the house CU internals, just to be sure in my mind, hopefully he will.

 

[Midwest]

Is it my iPhone screen (small), or is there a blue wire going from the neutral bar to the earth bar. Haven’t got my reading glasses?

 

[buzzlightyear]

why has the op put a 32 amp on a radial or is it a ring ring a roses .

 

[Midwest]

Is it my iPhone screen (small), or is there a blue wire going from the neutral bar to the earth bar. Haven’t got my reading glasses?

Naah found em and it’s not.

 

[buzzlightyear]

Naah found em and it’s not

lol .

 

[Silly Sausage]

View attachment 48035lol .

Is he your mate, Captain James T. Jerk?

 

[John Chalmers]

John can you post a pic of the house CU internals please?

Pete, been out. Picture attached. Flexi conduit coming up from under the floor. See the brown wire going into middle mcb and tell-tale blue wire going into neutral bar. Cheers.

 

[Pete999]

Swap the N to the other N bus-bar

 

[buzzlightyear]

Swap the N to the other N bus-bar

I bet you are itching to go and do it ,hay Pete.

 

[ChrisElectrical88]

Why a 16A radial to the shed then a ring main on a 32A in the shed, wheres the thinking in that?

Also why have you energised before initial verification was carried out?

Anyone mentioned exporting the earth to the shed yet

 

[Pete999]

I bet you are itching to go and do it ,hay Pete.

Yes right