DIY - new oven tripping DB. Electrical Advice

DIY - new oven tripping DB. Discussion ThreadDIY - new oven tripping DB. Electrical Advice

hello all,

btw I'm a plumber.... do I hear groans?! I installed a new Neff oven, DB is 0.5m away through a wall, wired into spare 16A MCB (house was built 2019) with 2.5mm T&E via 20A switched outlet, manufacturers lead with moulded plug (wired into outlet - not shortened).

... plug lead into oven... pop... both RCD's trip.
... switch outlet on... ditto
... switch MCB on... ditto

Neff engineer came out, no difference... tripping RCD. Tested the oven with his test lead plugged into ring-main, absolutely fine, no issues. Conclusion: is the Neff lead is faulty, OK. (No replacement lead on vehicle!) replacement lead sent via courier turns up 4 days later.

... wired up new lead... pop... same issue.
OK, wired up original lead Neff into plug; plugged into extension lead, plugged into ring-main... oven fires up, no issues!

What am I doing wrong?? Is the 16A MCB faulty? Do I need to check continuity of 2.5mm T&E?

Please help...

Regards
Jim

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