Electric shower cuts out after 5 mins

[CrazeUK]

B32

 

[terryplumb]

Does this mean I need to get a higher amp MCB for it?

I have only opened the consumer unit once to replace one of the other MCB's. Is it legal for me to replace or do i need to get a qualified electrician to do it?

No ,you can't just swap the MCB for a higher rated one before establishing the size of the cable it's protecting.
What exactly is the kilowatt rating of the shower ?

 

[terryplumb]

Is it not the same as the printed one at the bottom then?

Yes it is ,I just didn't see the lower info.

 

[terryplumb]

What did you replace in the past ? Hopefully not a higher amperage breaker than was there originally ?

 

[CrazeUK]

That's a very good question

No ,you can't just swap the MCB for a higher rated one before establishing the size of the cable it's protecting.
What exactly is the kilowatt rating of the shower ?

That's a very good question. I had the shower unit replaced some years ago. I THink it was a 9.5kw.

I was just thinking, the run from the CU to the trip switch is only a few meters. Would it be worth replacing that for a 16mm for future proofing. The trip switch is directly behind the shower in the kitchen, so that would be easy to replace. I wouldn't do the trip to shower my self

 

[CrazeUK]

What did you replace in the past ? Hopefully not a higher amperage breaker than was there originally ?

No, it was like for like.

 

[terryplumb]

No, it was like for like.

Ok.
A 32amp circuit is wholly unsuitable for a 9.5kw shower. That would draw around 41 amps at 240 volts.
Hence the 32amp MCB is tripping. How many years has the shower been running on that breaker ?

 

[CrazeUK]

Ok.
A 32amp circuit is wholly unsuitable for a 9.5kw shower. That would draw around 41 amps at 240 volts.
Hence the 32amp MCB is tripping. How many years has the shower been running on that breaker ?

It was installed around 5 years ago by a electrician.

Once I confirm the actual kW rating, what would I need for a 9.5?

 

[terryplumb]

My advice would be install a 10mm² T&E cable , if it isn't already ,and 45amp MCB. If you have an isolation switch on the circuit that may need to be upgraded to a similar amperage rating .
A site visit by an electrician who can establish the existing cable size , Length and installation method may judge it possible to just upgrade the MCB.

 

[CrazeUK]

The cable is in ducting, so I can double check that. The total length is close enough to about 4m.

 

[CrazeUK]

P.s. thank you all for the help and information this far

 

[terryplumb]

Have a look at the cable ,the size should be embossed on the outer sheath.
It not ,show us a pic of the wiring inside the shower , particularly the earth conductor ( power off first obviously).

 

[CrazeUK]

This is what is embossed on the cable:
BASEC 078 BS6004 6242 YH 2 x 6 + 2.5 PX 42

 

[terryplumb]

The cable is 6mm². And the showers Kwatt rating is as you thought it was ,9.5kw.

 

[CrazeUK]

I assume that reads from "2 x 6 + 2.5 PX 42"
2 x = 2 core
6 = 6mm²
+ 2.5 = 2.5mm cables in the cores?

Given its a 9.5kw and assuming under rated cable, are we still suggesting going with a 10mm cable, a 45A MCB and potentially isolated upgrade to 45A (if not already)?

Having opened the shower unit, it looks like a strait swap and pull through job to change the 30cm of cable between shower unit and isolator.