Cable guide for new 8.5kw shower

[Win2Kuser]

Hi, first post, so please be gentle with me lol

Okay, basically, our bathroom has a shower on/off pull switch, but no shower, so we're attempting to fit one.

Not so long ago, a sparx friend of mine checked the pull switch and said it was live and all I needed was to drop some 10mm cable over the top and chase it down behind some conduit or tiles etc into a shower. He also said that I should only get an 8.5kw shower.

So, I have the shower, and I've started installing it, but I think I've got myself confused with the cable and bought the wrong stuff; especially comparing it with the thick cable leading from the chock box inside the shower.

I was under the assumption that 10mm cable was literally 10mm physical size, which in Homebase was listed as ring main cable. Looking closer at the cable, it's actually made up of 2.5+2.5+1.5 cores, and the markings are as follows;
BASEC TO BS 6004 6242 YH 2X2.5+1.5 SQMM ALTIN 2010 4

Searching on google, it looks like you add the core sizes up to get the size, so a 4mm + 4mm + 2mm would be the right cable? Also, on fleabay, searching for 10mm shower cable returns items with the description 6242 which this one has.

I did ask on the screwfix forum, but just got a silly reply making out I was having a laugh... not sure if it was a good thing or a bad thing!

The cable incidentally, is only around 2.5mtrs long from the pull switch to the shower.

So, question is, is the cable I have bought suitable, or will I need to rip it all out?

Thanks in advance,

Mark

 

[riveralt]

STOP!!!

Before you start you need to speak to your Local Authority Building Control because this installation will need to be notified to them.

Some questions:

What is the size of the cable running from the consumer unit to the pull switch?
What is the size of the MCB protecting the cable?
Is the circuit protected by an RCD?
What do the manufacturers instructions say in so far as the cable size and the MCB size?

Given your lack of knowledge displayed so far it may be better if you get an electrician in fix your shower.
Perhaps the screwfix forum had come to the same conclusion - not sure why you would expect a different response here.

 

[bernardgreen]

Please stop and get an electrian to install the electrics to the shower.

The cable you have is totally inadequate and if used will create a serious risk of damage to your new shower ( terminals over heating and melting the case without any fuse blowing ). It may also create a serious risk of fire, if the cable does suffer damage from over heating then it may leave the shower unit live, very likely to be FATAL for anyone using the shower.

 

[Win2Kuser]

Great, thanks guys, I knew I should have come here first.

Why would I expect a different answer to screwfix? It was a simple enough question. I asked a question, I didn't expect sarcasm and silly comments, if the bloke said that to my face, I'd rip his head off! I don't know why people can think they can say anything on forums because they're hidden behind a monitor

Thanks for your help anyways. What I was planning on doing was install it myself, then get it checked over before using it. So, I obviously took the 10mm size literally, if I do get the full 10mm cable from say fleabay, it would be okay? I'm generally okay when it comes to things like this, just got my wires crossed (no pun intended) over the cable size, anything I ever do concerning electrics, I always get checked before use, but I like to fit it myself, one for sh1t and giggles, and 2 to save money.

The instructions on the shower are very vague to say the least, it just says to use 20mm conduit if required.

I've had a look at the trip switch, and it says Crabtree MCB B32 61/B32. Looking at the cable, it's a hell of a lot thicker than the crappy stuff I got! It's about 16mm width, so presumably the core sizes are a lot thicker!

So was I right with adding the core sizes up? 10mm actually means 4+4+2, or is it something to do with mm squared or something?

Thanks again

 

[bernardgreen]

So was I right with adding the core sizes up? 10mm actually means 4+4+2, or is it something to do with mm squared or something

NO you were WRONG about 4+4+2

10mm cable is 10mm² ( ten square millimetres of copper ) cross section in EACH of the Live and Neutral conductors. The protective earth conductor is a bit smaller.

The vague installation instructions probably included a sentence similar to

The elecrical supply for this equipment must be installed and tested by a qualified electrician

Lack of knowledge and/or information can result in an error or omission in the installation with serious or fatal consequences. Your confusion over cable sizes shows clearly that you do not have the knowledge to install the shower.

 

[holmslaw]

..

 

[ban-all-sheds]

Searching on google, it looks like you add the core sizes up to get the size, so a 4mm + 4mm + 2mm would be the right cable?

Where on earth did you read that nonsense?

Why would I expect a different answer to screwfix? It was a simple enough question. I asked a question, I didn't expect sarcasm and silly comments, if the bloke said that to my face, I'd rip his head off! I don't know why people can think they can say anything on forums because they're hidden behind a monitor

You asked a question which displayed such a staggering level of ignorance that it was quite reasonable to think it was a wind up.

I guess, like me, fooman finds it really hard to understand why someone who must know that he knows SFA about electrics nevertheless decides to plunge in and install a mix of water and a large electrical load, in contravention of the law.

What I was planning on doing was install it myself, then get it checked over before using it.

Of course you were.

So, I obviously took the 10mm size literally

No, you took it in complete ignorance of the things you need to know.

if I do get the full 10mm cable from say fleabay, it would be okay?

You tell us. How do you plan to do the continuity, insulation resistance, polarity and EFLI testing?

anything I ever do concerning electrics, I always get checked before use

I'd be interested to hear from any of the people here how often they "check things over" for DIYers, and what they actually do.

but I like to fit it myself, one for s**t and giggles

You're a t**t.

 

[sparkwright]

(sigh) Another satisfied op...

 

[holmslaw]

..

 

[sparkwright]

Not so long ago, a sparx friend of mine checked the pull switch and said it was live and all I needed was to drop some 10mm cable over the top and chase it down behind some conduit or tiles etc into a shower.

Mark

Out of interest, what size cable was feeding the pull switch?

 

[sparkwright]

You may wish to answer quickly, I have a feeling this topic is soon to become 'locked'.

 

[bernardgreen]

why don't people like Argos, or at least in the instructions, tell you about them.

[1] it would reduce sales and profits

[2] the people working there often have no knowledge of what they are selling.

[3] if they mention there may be a hazard with DIY install they would open themself to litigation for selling something they admit may create a hazard.

 

[ban-all-sheds]

why don't people like Argos, or at least in the instructions, tell you about them.

[2] the people working there often have no knowledge of what they are selling.

Example:

The cable was bought from Homebase, the person cutting the cable was made aware of what I was buying the cable for, and he said that it was fine for it.

Also..

[4] Is it their job? The same sorts of places sell bricks, sand, cement, timber, windows, doors, tiles etc etc - you could rock up to a large DIY shed in a large truck and drive off with a self-assembly house.

Do they tell you that you need planning permission and Building Regulations approval to build a house?

No - you're expected to know.

Go to a car dealer and buy a car. Do they tell you that you need a driving licence and insurance? No - you're expected to know.

 

[Click4]

I agree BAS it is not their job to know,

although reservedly I do think the staff should have an adequate knowledge to properly advise customers. Because it is a DIY store after all so to a certain degree the staff have to expect to be asked questions every now and again.

But like you say, it is the responsibility of the customer to stay within the law.

Hence why you can go out and buy boilers, gas fittings etc on a no questions asked basis lol as the seller is more interested in the sale than whether you "should" be doing what you are as that falls upon your own responsibility.