Type A rcd for cooker or type AC OK?

[HappyHippyDad]

My builder has sprung a job on me.
New circuit required for a hob.
The CU has a single 30mA RCD, type AC.
I am still unsure exactly when I should insist on type A, and when I should just advise.

Would you guys be insisting on type A in this case, thus fitting a new CU (as it is an old NSB wylex board with an RCD taking up 3 slots (WSES 100/2). Pretty sure there wouldn't be a type A available)).

The MI would be interesting to read, but I don't have them.

Not sure how be are supposed to determine if there is a possibility of pulsating, residual DC.

Thanks.

 

[bill01803]

If it is an induction hob it needs to be type A
If it is a hob with elements AC will do

 

[Risteard]

You need to bear in mind what else is on that RCCB, and which could prevent it from operating correctly. It's not just the load you're adding which is relevant - DC from other parts of the installation could render the RCD protection ineffective for your addition/alteration.

 

[Rockingit]

We should always 'advise', as our recommendations to clients should always be based against current best practice. However, whether we need to 'insist' is an entirely different animal. For example - in the unlikely event that the cable feeding the circuit is surface clipped then there's no need for any RCD in the absence of a MI that stipulates one (assuming no socket outlet on the oven switch....). As already said above, whilst my personal gut tells me you'll be fine to stay on an AC, only you know what you're installing and what's there already. Also, one assumes that there was an existing oven/hob as part of the original install anyway?

 

[HappyHippyDad]

We should always 'advise', as our recommendations to clients should always be based against current best practice. However, whether we need to 'insist' is an entirely different animal. For example - in the unlikely event that the cable feeding the circuit is surface clipped then there's no need for any RCD in the absence of a MI that stipulates one (assuming no socket outlet on the oven switch....). As already said above, whilst my personal gut tells me you'll be fine to stay on an AC, only you know what you're installing and what's there already. Also, one assumes that there was an existing oven/hob as part of the original install anyway?

You would think there is already one there, but the builder hasn't mentioned this. He's pretty savvy, and I believe he would have mentioned this during our chat if there was one.