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.

 

[ChrisElectrical88]

Deleted wrong thread haha

 

[Norah Nabino]

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.

The RCD might be faulty as well.

 

[ChrisElectrical88]

And the upfront protective device is a 16A MCB so why would you?

Read the thread


Edit, Also that RCD is not faulty, atkeast it wasnt when he started doibg bang tests. Hes fluffed up somewhere.