Turn off hob and both MCB and RCD trip.

[telectrix]

And although unrelated to the current issue having both lighting circuits via the one RCD is poor design, especially with elderly customers.

and the house should have 2 separate 100A supplies, so if 1 goes down, the other will still give them power and lights.

 

[Dave OCD]

Are you on the beer Tel ?

 

[The Ghost]

When they are switched off are they off load? I am thinking something wrong with the switches. If as you say the observers/reporters are not the sharpest knife in the draw, it seems you may have to verify what has been stated.

 

[Wilko]

By all means make checks, but I'm thinking the induction hob is not working correctly. It should not trip the MCB instantly ...

 

[elsparko]

disconnect the hob if problem is solved buy a new one, occams razor

 

[Grezza]

Ah, the clue is Induction hob. Often these have a lot of filter capacitiance L to E and N to E that can cause transient trips. Check the installation with a 500V megger to see if there are any other issues, and you might want to move the hob to it's own RCBO

I second this.

 

[DC-backfrom the past]

as above .............maybe a faulty switch on the hob. not closing properly and sparking causing the fault ?

 

[Risteard]

I can't envisage a fault that would trip both.

I can: a phase to Earth fault.

 

[satori]

An update, in case anyone's wondering how I'm progressing:

Employer hasn't let me have the tester yet, so no progress. Will report back as soon as I make progress. Thanks all for the comments so far.

 

[elsparko]

An update, in case anyone's wondering how I'm progressing:

Employer hasn't let me have the tester yet, so no progress. Will report back as soon as I make progress. Thanks all for the comments so far.

does the circuit work without the hob connected? if so then thats your problem solved

are you going to be testing the internals of the hob? if it is the faulty oven and nothing to do with the actual circuit then i feel you may kick yourself when you find out how much parts cost + labour vs a whole unit

ive got 99 problems but a hob isnt one.