Replacing a shower

[asad44]

Hi folks,


In need of some advice, prior to replacing my shower. The unit that i have bought is 9.5kw. However, having read and calculated fuse requirements, i think i might be under fused. To give you some particulars, the shower cable is 10 mm, i cannot establish what rating (kw) the existing shower was, the fuse is a cartridge type enclosed or plugged into one of those older looking fuse things, not a circuit breaker and is 30A. The main board has a 60amp fuse. I think i may need a 40-45 amp fuse but having read some comments on here and other forums apparently it is not recommended to put in a 40 amp fuse into a board that has a 60 amp limit. I hope this makes some sense. So the questions are these:

1- can i buy and use a 45a fuse with my existing circuitry?
2- if not, what do i need to do?

I can provide pics if necessary, any comments very welcome.


Thanks in advance.

 

[LearningSpark]

When you say the cable is 10mm is that the measurement across the cable or is that what is written on the grey outer sheath?

 

[bernardgreen]

What size is the cable and where does it run as those are the limiting factors of the power the shower can be. ?

 

[asad44]

Thanks for the quick replies.


10mm is the measurement across the cable, i cant see any writing on the visible part of the cable.

The cable runs from the shower into the loft across the house then down to the the main board, i would estimate about 17m? The cable runs through the wall cavity.

 

[Mursal]

Might be worth just throwing your eye on the RCD/ELCB in the fuse box.

It has a test button and trips on test, and a trip current of 30mA, yes?

 

[asad44]

Mursal, thanks for reply.


But i dont have a circuit breaker on the shower it is a cartridge based fuse enclosed in an old ceramic type holder.

 

[asad44]

Untitled

• asad44
• 5 Aug 2012
• 1

 

[LearningSpark]

If the cable is only 10mm across then it sounds like 2.5mm2 cable which is no where near big enough for your new shower. You need an electrician to upgrade your feed to the shower and provide you with RCD protection.

 

[RF Lighting]

You are going to have to have that fuse box replaced as the maximum fuse it will take is 30A, and your circuit is required to have RCD protection which your fuse box can not offer.

Also your cable does not look like it is 10.0mm²

There is a guide to sizing cables here:
//www.diynot.com/wiki/electrics:cable_types:flatpvccables