Electric shower cuts out after 5 mins

[Johntheo5]

You should not change the MCB for one with a higher rating if that's your intention.
The person that installed the circuit has judged that a 32amp breaker was suitable to protect the circuit cable.
Your shower appears to be drawing current at a level that the existing cable is carrying at its upper limit within its method of installation.
Do yourself a favour and engage an electrician to install an upgraded circuit

Yes, Very good point.

I was in a house a few years ago where the house owner had his 9kw electric shower (with 6mm2 cable and protected with a 40A/30ma RCBO) changed to a hot&cold integrally pumped Triton AS2000XT shower and who ever had installed it had left the the same RCBO and wiring in place, don't know how the 6mm2 cable was terminated in the shower but the same cable certainly appeared to (rear) enter the shower, this shower probably only draws a amp or two so was/is this against regulations or, at least should the the RCBO have been changed to a 5A or whatever?.

 

[terryplumb]

The overcurrent protective device is there to protect the circuit cable from carrying current in excess of what it can safely carry. Putting a shower on that draws less current than the original shower isn't an issue.

 

[bernardgreen]

So both then. I will change the MCB first as that is the more economical and shorter time change. See if that has any impact. Then swap the cable out

Changing the MCB to a higher rating will ( probably ) prevent the shower from cutting out but will mean the cable will not longer be protected from overload, The overheating of the cable will be increased as the higher rated MCB will not be cutting power

Replace cable first, then the MCB,

 

[Johntheo5]

To stay within regulations maybe get a new 32A MCB installed, if the tables below are accurate and your cable load is 38A then that MCB theoretically shouldn't trip for between 15 and 25 minutes, all a bit borderline I suppose.,