New shower not heating up hot.

[diycooper]

I have had a new 8.5kw shower installed.

It is installed with 6mm cable clipped with a 32 MCB.

The shower is getting warm but not hot.

Could it be the fuse needs changing t0 a 40 amp as 8.5kw is roughly 37 amp ?

Would the shower still not get hot but trip if this was the case so I suspect a fault with the shower ?

 

[PrenticeBoyofDerry]

What device rating does the MI say the shower needs?
And what voltage rating is the power/current being calculated?

Also the voltage drop and method of installation must be factored into this, it is possible that a 6mm T&E cable cannot be safely protected by a 40A device.

 

[PrenticeBoyofDerry]

Would the shower still not get hot but trip if this was the case so I suspect a fault with the shower ?

I have seen showers rated at 8.5kW run on a 32A breaker without tripping it.
It would depend on how long the the overload is allowed to continue, to if the device will trip.

 

[oldbutnotdead]

Changing the MCB will make no difference to how well the shower heats the water. MCB will either permit current to flow or will trip- a 32A MCB supplying a 40A load won't 'throttle' the supply to 32A- it'll pass 40A for a while and then it'll trip.