mistermarantz Registered User

I have an old 8.5KW Triton electric shower for the last 10 years which needs replacing. I have bought a new 8.5KW electric shower and I'm hoping someone can help me.

I read the instruction manual of the new shower and it recommends a 10mm cable and a 40 amp MCB for showers over 8KW

I checked the set up of my old shower and it was wired with 6mm cable and the fuse box has a B32 amp MCB. The shower is approx 4m away from the fuse box.

Even though my old shower has worked fine for the last 10 years, can someone please advise me if the correct cable and MCB was installed from day 1??

Is 6mm cable and a B32 MCB safe for a 8.5KW shower??


In my opinion the 6sq is fine but I would change the 32amp mcb to a 40 RCBO.

Avns1s Registered User

I agree, the 6 sq. should be fine for a short run like that. But I would change to the RCBO as Woddle says.

mistermarantz Registered User

Folks, thanks for your help

Whats the difference between a MCB and a RCDO?

Also, what does the "B" in B32 mean?

davelerave Registered User

Ya.cables fine for 8.5kw at 4metres but change to 40a rcbo.Might need a small rewire if the existing 32 is already fed via an rcd .
Get a sparkie to test wiring at shower when finished

davelerave Registered User

The rcbo combines the overload/short-circuit protection of an mcb with the earth-leakage protection of an rcd.The 'B' denotes the magnetic tripping characteristic and is the type you need for shower

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