Shower upgrade and mcb size

[Paul Lathan]

Hi there.I am looking to upgrade my daughters shower in her flat.The shower is a 7.5kw at the moment,but is struggling with producing a decent temperature with the weather as it is.I was aanting to put in a 9.5kw instead.I have checked the cable from the mcb to the pull switch,and by posts i have read,seems to be 6mm.This runs about 6 feet to the switch,and another 6 feet from the switch to the shower.I have added photos of the fuse which is on its own board,which reads 63A.Am i missing something,as I was prepared to upgrade 6mm to 10mm,but unsure why such a large fuse.Any help would be greatfully received.cheers

 

[Andy78]

Upgrading of the cable will be notifiable to building control and should be installed and tested by a competent electrician.

 

[GMES]

Also the 63amp you refer to is the main rcd, I'm guessing the 50amp next to it is for the shower

 

[Deleted member 105166]

There's a 63A RCD and the shower is on a 50A MCB, 10A larger than it currently needs to be. But what feeds that board? Is it a sub main and if so what size breaker and cable feeds it from the main board?

 

[Dave OCD]

Paul, the 63a you refer to is the current capacity of the RCD ,in other words it's designed to handle that amount of current. The overcurrent protection is currently a 50 amp MCB rather than a fuse, this unit would have been bought as a 'Shower unit'. For the length of cable run you describe and assuming it's not covered by any insulation I'd say you could go up to 9kW safely with the new shower unit. But remember this is a notifiable job under Part P.

 

[Dave OCD]

Upgrading of the cable will be notifiable to building control and should be installed and tested by a competent electrician.

Yes there are plenty of things that should happen Andy.

 

[Andy78]

Yes there are plenty of things that should happen Andy.

Just my advice to a father who will obviously want the best in terms of safety for his daughter

 

[Wilko]

Hi - if I could advise you - this is not something you can take on as a DIY project. I've fixed a few that have had potential to be deadly without the upgrade you're contemplating. There's just no way I know for you to learn enough from the internet to safely undertake this job.

 

[The Ghost]

Is the flat her own or rented? Working 10mm and effectively terminating it properly and testing afterwards is a skilled job. If rented make sure the Landlord has agreed. I have never like the idea of standing under an electric shower so counter-intuitive.

 

[Bobster]

Hi - if I could advise you - this is not something you can take on as a DIY project. I've fixed a few that have had potential to be deadly without the upgrade you're contemplating. There's just no way I know for you to learn enough from the internet to safely undertake this job.

I wouldn't say that, all the information needed is online to do this job.

However, the time taken to do this and the cost of test equipment, notification etc... It's just far easier and a lot cheaper to bring a qualified electrician in.

 

[telectrix]

hmmmmm. a 50A MCB is a bit of a low rating to provide over current protection for 6.0mm cable, but..... a sthe shower is a fixed load then it only needs short circuit protection. a 9kW shower is within the capability of 6.0mmcable, assuming not in insulation, so a shower replacement on the existing circuit should be straight forward. if in doubt though, consult a competent spark.

 

[westward10]

Delete.

 

[Dave OCD]

Don't you mean a bit too high a rating Tel ?

 

[telectrix]

Don't you mean a bit too high a rating Tel ?

yep. my bad.

 

[Rpa07]

Yep and that run in the photo looks pretty itchy poo free and full of free air making a good ccc for a ‘slight’ upgrade (by a competent qualified electrician!)

 

[Dave OCD]

I'd also just double check that as the existing shower is a 7.5kW that the existing cable is 6mm and not 4.....

 

[Wilko]

I wouldn't say that, all the information needed is online to do this job.

I was thinking that some level of supervised work experience would be a prerequisite for the design, installation and testing of electrical equipment. Perhaps I am wrong?

 

[Bobster]

I was thinking that some level of supervised work experience would be a prerequisite for the design, installation and testing of electrical equipment. Perhaps I am wrong?

I'm being pedantic.

Of course it's easier to learn under supervision, but it's only basic maths and being able to and have access to in most cases fairly simple data.

 

[buzzlightyear]

what I like to know is the land lord ok with this if it is rented out to his
daughter, and ripping out the said cable to the shower .and put a bigger cable for a shower like Niagara falls!