Buying a new shower

[mo2]

Hi, I am looking to have an electric shower installed in a current bathroom. As far as I know the cable already there is 6.0mm, but I am not toally sure. Today, I will be trying to find out the length of this cable and the route it takes. I also will try and see if it has been terminated in the CU and is so where etc.

Is there any tips you can give me. If I find the fuse it has been connected to, can I then use that fuse value to work out what shower I can get?

Thanks very much

 

[ColJack]

no, the cable rating and route is what defines your maximum shower size..

it's no good having a 50A breaker in the board if the shower is wired in 6mm run through 10m of loft insulation...

6mm T+E clipped direct (ref method 1 ) is 47A... = 11KW ( roughly.. )
6mm T+E insulated (ref method 15 ) is 35A... = 8.5KW ( roughly.. )

( all calculations based on voltage of 240V )

 

[mo2]

OK, I have had a good look and followed the cable.

It starts at the CU (dont know if it is connected ) and runs freely 4.6m paralell to all the cables the provide the house. After that 4.6m it runs up a breeze block wall 2.4m. When it pops out of the wall into the attic and in the attic 17.1m of it is sitting on top of the insulation. It also goes under two wooden planks in the attic. The end of it has some tape around and is sitting in top of the bathroom we want to install the shower in.

So, what sort of shower can I have if I leave it sitting on the insulation?
If I clip it above the insulation?


Thanks for your efforts/help/replies

 

[securespark]

I assume from your description, there is no isolation switch for the shower.
In this case, I have added a few metres to allow for this.

So, with a run of 27m, volt drop at 35A is around 7V, which is OK.

With Method 4, which is the worst case scenario in your cable run, 35A is the maximum allowable load.

At 230V, this is 8 kW. However, I have done no correction for grouping.

Bear with me, unless someone beats me to it...

 

[mo2]

I assume from your description, there is no isolation switch for the shower.
In this case, I have added a few metres to allow for this.

So, with a run of 27m, volt drop at 35A is around 7V, which is OK.

With Method 4, which is the worst case scenario in your cable run, 35A is the maximum allowable load.

At 230V, this is 8 kW. However, I have done no correction for grouping.

Bear with me, unless someone beats me to it...

Thanks v. much for that, sounds OK, how do you correct for grouping?

We are thinking about 7 or 7.5kw shower...