Discuss Size of shower cable in the UK Electrical Forum area at ElectriciansForums.net

B

Bensen

Hey what kilowatt showers can be feed off 6mm cable and which need 10mm? I guess the distance from the fuse board also needs taking in to account?
 
Hi Bensen, distance plays a big part along with other factors including overcurrent protection and installation methods. I see from your profile that you are a plumber so IMO you should leave electrical cable calcs to the sparks.
 
Thanks would many sparks also do the plumbing on an electric shower. Its a swap or a 25year old plus electric shower that has stopped working.
 
considering the last plumber that i last had fit the water supply to a shower... brought it out 2 ft. below where i'd marked the studded wall, so the shower unit would have been only 2ft. above the bath and the cable 2 ft. above the shower, i do my own shower pipework now.
 
Hey what kilowatt showers can be feed off 6mm cable and which need 10mm? I guess the distance from the fuse board also needs taking in to account?

Each shower install would need to be assessed and designed on an individual basis and in accordance with appendix 4 of the regs. The kW rating of the shower and cable length are just 2 of many factors involved. This is definitely a job for someone who has been properly trained in circuit design.
 
Very broadly speaking up to 8.5kw on a 6mm
8.5kw to 10kw will need a 10mm
You need to consider some very important variables including,
The installation method ie is the cable run enclosed in some way or clipped direct.
Is the cable running within some form of insulation ect.
To explain,
The cable under load generates temperatures above ambient, and its ability to dissipate those temperatures will be greatly affected by the way its installed.
You also have to consider the length of run as this can affect the difference between the supply voltage at source and the voltage at the load/shower terminals.
This is known as volt drop and directly relates to the internal resistance of the cable per metre, in relation to its cross sectional area.
The characteristics of the protective device are also important as you need to ensure that the device disconnects the supply before the user of the shower receives an electric shock, should a fault condition develop.
The installations integrity need to be verified to ensure insulation,polarity, along with a low resistance earth return path are able to satisfy these requirements.
A certificate recording these results is produced to provide a paper trail for future reference.
Building regulations under part P also come into play when working in bathrooms as they are known as a special location, and these are divided into various zones for compliance.
If all this makes sense to you and you have the appropriate test equipment and knowledge to use it, then your good to go.
If not, consult a qualified electrician.:icon12:
 
Very broadly speaking up to 8.5kw on a 6mm
8.5kw to 10kw will need a 10mm

You need to consider some very important variables including,
The installation method ie is the cable run enclosed in some way or clipped direct.
Is the cable running within some form of insulation ect.
To explain,
The cable under load generates temperatures above ambient, and its ability to dissipate those temperatures will be greatly affected by the way its installed.
You also have to consider the length of run as this can affect the difference between the supply voltage at source and the voltage at the load/shower terminals.
This is known as volt drop and directly relates to the internal resistance of the cable per metre, in relation to its cross sectional area.
The characteristics of the protective device are also important as you need to ensure that the device disconnects the supply before the user of the shower receives an electric shock, should a fault condition develop.
The installations integrity need to be verified to ensure insulation,polarity, along with a low resistance earth return path are able to satisfy these requirements.
A certificate recording these results is produced to provide a paper trail for future reference.
Building regulations under part P also come into play when working in bathrooms as they are known as a special location, and these are divided into various zones for compliance.
If all this makes sense to you and you have the appropriate test equipment and knowledge to use it, then your good to go.
If not, consult a qualified electrician.:icon12:

You have just given this plumber a green light IMO lol
 
Very broadly speaking up to 8.5kw on a 6mm
8.5kw to 10kw will need a 10mm
You need to consider some very important variables including,
The installation method ie is the cable run enclosed in some way or clipped direct.
Is the cable running within some form of insulation ect.
To explain,
The cable under load generates temperatures above ambient, and its ability to dissipate those temperatures will be greatly affected by the way its installed.
You also have to consider the length of run as this can affect the difference between the supply voltage at source and the voltage at the load/shower terminals.
This is known as volt drop and directly relates to the internal resistance of the cable per metre, in relation to its cross sectional area.
The characteristics of the protective device are also important as you need to ensure that the device disconnects the supply before the user of the shower receives an electric shock, should a fault condition develop.
The installations integrity need to be verified to ensure insulation,polarity, along with a low resistance earth return path are able to satisfy these requirements.
A certificate recording these results is produced to provide a paper trail for future reference.
Building regulations under part P also come into play when working in bathrooms as they are known as a special location, and these are divided into various zones for compliance.
If all this makes sense to you and you have the appropriate test equipment and knowledge to use it, then your good to go.
If not, consult a qualified electrician.:icon12:
Stuff and nonsence :biggrin:
 
Very broadly speaking up to 8.5kw on a 6mm
8.5kw to 10kw will need a 10mm

You have just given this plumber a green light IMO lol

And a green light on advice that is wrong!

Why do people persist in their quest to not only help people do things they shouldn't be doing, but to give them duff advice as well?!

I wouldn't go as far as to say 'blind leading the blind' in this particular case. But at least get it right before you advise people to do what they shouldn't be doing. Better still though, just don't advise at all unless that advice is plainly and simply; "get a qualified electrician in".
 
Thanks would many sparkys be able to take care of the plumbing too. Its an old 25year plus shower that needs swapping.

Comments removed for the sake of forum decorum and in fear of a wrapping on the knuckles by learned professionals.
I do love em though xx
 
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And a green light on advice that is wrong!

Why do people persist in their quest to not only help people do things they shouldn't be doing, but to give them duff advice as well?!

I wouldn't go as far as to say 'blind leading the blind' in this particular case. But at least get it right before you advise people to do what they shouldn't be doing. Better still though, just don't advise at all unless that advice is plainly and simply; "get a qualified electrician in".

I'm terribly sorry, you are of course quite correct.
The cable selection regarding 8.5kw to 10kw on a 10mm is vague and ball park, but other comments were in the post regarding this.
My point is its not a simple answer.
But getting a qualified electrician is not an easy thing these days.
You can think your a qualified electrician, and then thankfully be reminded that clearly your not.
And that's where I now find myself.
So my advise to the original poster with corrections in place is
Get a qualified electrician, and in future I will do likewise.
Thank you once again for your advice.
 
And a green light on advice that is wrong!

Why do people persist in their quest to not only help people do things they shouldn't be doing, but to give them duff advice as well?!

I wouldn't go as far as to say 'blind leading the blind' in this particular case. But at least get it right before you advise people to do what they shouldn't be doing. Better still though, just don't advise at all unless that advice is plainly and simply; "get a qualified electrician in".

This is why I very rarely dish out any advice on here (not that I could anyway!); sketchy 1st posts, don't know who's asking, can't see the site ... list goes on.
 
Of course all the above is very true.
So difficult to judge the integrity, knowledge, experience, or competence of anybody on this forum.
And I do mean anybody.
Some are no doubt very nice, genuine people, with a wealth of experience under there belt.
Others are arrogant self obsessed masters of there universe who probably make a living sucking on the experience and hard work of the genuine electrician.
Of all the electrical consultants, technicians, engineers, and qualified electricians I have known and respect. Not one of them is or has been a member of this forum. Or feel any need to be so.
I come on here when a little bored and enjoy the banter.
I have spent a lovely evening with friends one of which is a telecoms engineer, the other a solicitor, and another has his own plumbing business.
Our wife's likewise enjoyed the evening, been talking about an up coming cruise that we are all looking forward to.
For me its time for bed, and for those who relate to my comments, and come here for similar reasons (and they know who they are)
I would say take any sarcasm, arrogance, or statements relating to the I no so much more than anyone else brigade with a pinch of salt.
There not an integral part of your life or mine in the real world.
And lets face it, the real world is full of, how shall we say, Plonkers. lol.
Have a really good night fellas, God bless xx
 
Thanks would many sparkys be able to take care of the plumbing too. Its an old 25year plus shower that needs swapping.
Then it aint a like for like saw, particularly given the requirement for RCD protection per manufacturers instructions. Can a plumber spell RCD? ;)
 
Of course all the above is very true.
So difficult to judge the integrity, knowledge, experience, or competence of anybody on this forum.
And I do mean anybody.
Some are no doubt very nice, genuine people, with a wealth of experience under there belt.
Others are arrogant self obsessed masters of there universe who probably make a living sucking on the experience and hard work of the genuine electrician.
Of all the electrical consultants, technicians, engineers, and qualified electricians I have known and respect. Not one of them is or has been a member of this forum. Or feel any need to be so.
I come on here when a little bored and enjoy the banter.
I have spent a lovely evening with friends one of which is a telecoms engineer, the other a solicitor, and another has his own plumbing business.
Our wife's likewise enjoyed the evening, been talking about an up coming cruise that we are all looking forward to.
For me its time for bed, and for those who relate to my comments, and come here for similar reasons (and they know who they are)
I would say take any sarcasm, arrogance, or statements relating to the I no so much more than anyone else brigade with a pinch of salt.
There not an integral part of your life or mine in the real world.
And lets face it, the real world is full of, how shall we say, Plonkers. lol.
Have a really good night fellas, God bless xx

With that mix of friends and technical ability you were probably best placed to help the OP! The plumber friend regarding plumbing, you regarding electrics, the telecom engineer for advice on avoiding their cables and the solicitor friend for legal advice when it all goes wrong for the OP! :D

P.S.
I'm afraid your god didn't bless me :(
 
I am working in a house at the moment where the customer has got a tiler in , and he's plastering all the walls , fitting bathrooms , fitting kitchens , installing plumbing , and when I went back he had all my electrical work apart and was playing with that , what hope is there in this country when customers don't give a ---- about proper tradesmen to do their work ...

I had a right set too with this guy , but the customer sees his work of more importance , so what chance have you got , just about anyone thinks they can dabble with our work.....
 
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Dear oh dear,
Talk about making a mountain out of a mole hill.
The original poster could gleam the information he requires from any web search or forum he wishes to visit.
It takes a simple google search.
And maybe that's where the real problem lies because as we all know a little knowledge can sometimes be dangerous.
The OP as an example could easily have visited this;

Shower Cable Size | Size Chart | Gainsborough Showers

And taken his info from there.
So in retrospect I was simply making the OP aware of the many variables required to ensure the install was safe and compliant.
6mm as said, will suffice in most instances for an 8.5kw shower
And from 8.5 to 10kw 10mm.
Once again the installation method and cable run along with other factors will dictate.
Safety is paramount and for that reason a qualified electrician is the sensible way forward.
And looking back that's exactly what I said.
So no I was not giving the OP the green light, I was simply making him aware that there is more to his question than he was aware of.
I pointed out that if he was unsure seek a qualified electrician.
Hardly a green light, and as a response certainly not a case of the blind leading the blind.
I am well aware of my level of competence, experience, and knowledge base.
Still learning actually as we all are.
We can have differences of opinion, and different levels of experience.
But I hold true to my belief that certain people on this forum have a very arrogant attitude, and as said come from the I know better than anyone else brigade.
We can all cross T's and dot I's looking for holes to pick in someone's comments, but that doesn't excuse rudeness or lack of respect.
We all come from different backgrounds and levels of experience.
Regardless of trade or profession there are decent people and there are silly billy's lol.
Its as simple as that, we are what we are fellas.:icon12:
 
We spend years a college(or at least most of us do) learning about cable cals the science behnid electrics and theory for a good reason. There is more than just what size cable due to Kw rating of the shower. What about earthing arrangements, Zs of the circuit, compliance with section 701 of the BGB.

So before you get on your high horse preaching about us being arrogant, make sure you give correct advice with everything in mind as you say a little knowledge can be dangerous.
 
We spend years a college(or at least most of us do) learning about cable cals the science behnid electrics and theory for a good reason. There is more than just what size cable due to Kw rating of the shower. What about earthing arrangements, Zs of the circuit, compliance with section 701 of the BGB.

So before you get on your high horse preaching about us being arrogant, make sure you give correct advice with everything in mind as you say a little knowledge can be dangerous.

Yes I did too, and agree.
That's all in my reply to the original poster, phrased somewhat differently but there.
My comments are not for you regarding arrogance. Your one of the nice guys and if you knew and worked with me we would be shaking hands and you would find me very different to what you perceive on a forum.
That's the shame of it.
 
Yes I did too, and agree.
That's all in my reply to the original poster, phrased somewhat differently but there.
My comments are not for you regarding arrogance. Your one of the nice guys and if you knew and worked with me we would be shaking hands and you would find me very different to what you perceive on a forum.
That's the shame of it.

I'm guessing the comments were for me regarding arrogance, and I'm guessing that's because you perceive me to be 'not one of the nice guys'.

Well guess what, I couldn't give hoot.

I certainly don't come from the 'I know better than anyone else' camp, far from it in fact, but your advice about 6mm for up to 8.5kW and 10mm for the rest, although a rough guide, is still wrong. It would be like me saying that a rough guide for sub mains is to use 16mm cable!? Well hang on a moment... What about a 200A sub main?!

You start giving people 'rough' guides and they will use them. It is in our nature to take a mile when given an inch.

There are situations where 16mm cable may well be needed for an 8.5kW shower and there are other situations when 6mm may well be just fine for a 10.5kW shower. You explain well that there are other issues that need taking into account but this guy is a plumber, he isn't going to know is he. For all you know he may be looking at your post and all he sees is "6mm is fine for 8.5kW". That is where the danger lies and was the only point I was making.

If you're going to be giving out advice to unqualified people it should be "get a qualified electrician", no more no less. The moment you start making them think that it is a job they can do themselves they are going to cease this opportunity aren't they! If they're the sort that know their limits they wouldn't be on here in the first place asking us how to do something they shouldn't be doing. What is worse however is not only providing advice that allows them to scoot off and start tampering with the unknown, but providing advice that hints at options that may well be unsuitable. In this case, you've nothing short of a recipe for disaster.

I know that a lot of people on here have the undying urge to 'help' others, all at the same time showing off what knowledge they may (or as is often the case 'don't) have and racking up their post count at the same time. All I'm saying is maybe sometimes, it's best to quell that urge.

If by saying this I come across as a d¡ckhead then so be it. I'd far rather be a d¡ckhead that doles out the right advice than a d¡ckhead that doles out wrong and potentially dangerous advice.
 
The other thought I have had for a long time is that as there are so many threads posted on this forum , there must be situations that cover almost everything , so anyone can register on here and search for something to give them the answer they want ...

I just tapped in 'Shower cable size required' on google and up came a selection including a thread on this forum from 2011 exactly what this guy needs ...
 
Last edited by a moderator:
duty_calls.png
 
I'm guessing the comments were for me regarding arrogance, and I'm guessing that's because you perceive me to be 'not one of the nice guys'.

Well guess what, I couldn't give hoot.

I certainly don't come from the 'I know better than anyone else' camp, far from it in fact, but your advice about 6mm for up to 8.5kW and 10mm for the rest, although a rough guide, is still wrong. It would be like me saying that a rough guide for sub mains is to use 16mm cable!? Well hang on a moment... What about a 200A sub main?!

You start giving people 'rough' guides and they will use them. It is in our nature to take a mile when given an inch.

There are situations where 16mm cable may well be needed for an 8.5kW shower and there are other situations when 6mm may well be just fine for a 10.5kW shower. You explain well that there are other issues that need taking into account but this guy is a plumber, he isn't going to know is he. For all you know he may be looking at your post and all he sees is "6mm is fine for 8.5kW". That is where the danger lies and was the only point I was making.

If you're going to be giving out advice to unqualified people it should be "get a qualified electrician", no more no less. The moment you start making them think that it is a job they can do themselves they are going to cease this opportunity aren't they! If they're the sort that know their limits they wouldn't be on here in the first place asking us how to do something they shouldn't be doing. What is worse however is not only providing advice that allows them to scoot off and start tampering with the unknown, but providing advice that hints at options that may well be unsuitable. In this case, you've nothing short of a recipe for disaster.

I know that a lot of people on here have the undying urge to 'help' others, all at the same time showing off what knowledge they may (or as is often the case 'don't) have and racking up their post count at the same time. All I'm saying is maybe sometimes, it's best to quell that urge.

If by saying this I come across as a d¡ckhead then so be it. I'd far rather be a d¡ckhead that doles out the right advice than a d¡ckhead that doles out wrong and potentially dangerous advice.

Considering your avatar you will probably appreciate the scene in the film Patton when the Russian general toasts him.
So with that in mind from one Dick Head to another Dick Head, I will drink to that.

With regards to giving poor advice on the cable sizing front.
I feel I have made it quite clear, in my original reply to the OP, that there are factors that need to be taken into consideration, not least length of run and installation method.
Its all there if you take the time to read it !!
And if my comments are without substance or merit I suggest you search the internet yourself, because like the OP its all there and far from a big hush hush secret these days.

Have a look for yourself,

Removed

Argue with the shower manufactures by all means.
Do I see 8.5kw 6mm mentioned there ??
At least others can judge for themselves, but that's not to say your not entitled to your opinion.
With reference to the majority of your comments I will say this.
I agree with you.
But the one regarding blind leading blind, bit harsh is that.
By all means don't agree.
But don't assume a guy doesn't know his stuff purely because his opinion differs with yours.
 
Last edited by a moderator:
Baldsparkies; I think the mistake you've made in post 10, is that you've virtually given the go ahead, then gone on to qualify your statement.
Should have gone the other way round.
The geezer will just see what he wants in your initial statement and ignore the rest!
 
Considering your avatar you will probably appreciate the scene in the film Patton when the Russian general toasts him.
So with that in mind from one Dick Head to another Dick Head, I will drink to that.

With regards to giving poor advice on the cable sizing front.
I feel I have made it quite clear, in my original reply to the OP, that there are factors that need to be taken into consideration, not least length of run and installation method.
Its all there if you take the time to read it !!
And if my comments are without substance or merit I suggest you search the internet yourself, because like the OP its all there and far from a big hush hush secret these days.

Have a look for yourself,


Removed

Argue with the shower manufactures by all means.
Do I see 8.5kw 6mm mentioned there ??
At least others can judge for themselves, but that's not to say your not entitled to your opinion.
With reference to the majority of your comments I will say this.
I agree with you.
But the one regarding blind leading blind, bit harsh is that.
By all means don't agree.
But don't assume a guy doesn't know his stuff purely because his opinion differs with yours.
Don't attempt to defend the fact a 8.5kw shower cannot be used on a 6mm2 cable, believe me you will lose the argument, we consider ohms law and several tables in BS 7671 as well as installation factors/ methods in BS7671 when calculating cable sizes, ahem, say no more, now crawl back into your fox hole, incomming
 
Last edited by a moderator:
Very broadly speaking up to 8.5kw on a 6mm
8.5kw to 10kw will need a 10mm

You need to consider some very important variables including,
The installation method ie is the cable run enclosed in some way or clipped direct.
Is the cable running within some form of insulation ect.
To explain,
The cable under load generates temperatures above ambient, and its ability to dissipate those temperatures will be greatly affected by the way its installed.
You also have to consider the length of run as this can affect the difference between the supply voltage at source and the voltage at the load/shower terminals.
This is known as volt drop and directly relates to the internal resistance of the cable per metre, in relation to its cross sectional area.
The characteristics of the protective device are also important as you need to ensure that the device disconnects the supply before the user of the shower receives an electric shock, should a fault condition develop.
The installations integrity need to be verified to ensure insulation,polarity, along with a low resistance earth return path are able to satisfy these requirements.
A certificate recording these results is produced to provide a paper trail for future reference.
Building regulations under part P also come into play when working in bathrooms as they are known as a special location, and these are divided into various zones for compliance.
If all this makes sense to you and you have the appropriate test equipment and knowledge to use it, then your good to go.
If not, consult a qualified electrician.:icon12:

this is about the only thing the plumber would of seen IMO.
 
Considering your avatar you will probably appreciate the scene in the film Patton when the Russian general toasts him.
So with that in mind from one Dick Head to another Dick Head, I will drink to that.

With regards to giving poor advice on the cable sizing front.
I feel I have made it quite clear, in my original reply to the OP, that there are factors that need to be taken into consideration, not least length of run and installation method.
Its all there if you take the time to read it !!
And if my comments are without substance or merit I suggest you search the internet yourself, because like the OP its all there and far from a big hush hush secret these days.

Have a look for yourself,

Removed

At least others can judge for themselves, but that's not to say your not entitled to your opinion.
With reference to the majority of your comments I will say this.
I agree with you.
But the one regarding blind leading blind, bit harsh is that.
By all means don't agree.
But don't assume a guy doesn't know his stuff purely because his opinion differs with yours.

Not quite sure what my avatar has to do with anything but hey ho.

For clarity, I wasn't referring to you as a dick head, rather that I am happy to be a dick head giving out right advice instead of wrong.

Also, I didn't quite go as far as to say 'blind leading the blind' did I?! I suggest you read that post in more detail.

Finally, with regards to helping people who don't know what they're doing, just because there is advice out there, that doesn't mean to say we as electricians should be adding to it. If you want to take an 'if you can't beat 'em join 'em' attitude that's your prerogative, but you won't catch me joining in. All I would say is that you should be a little more careful in future that the advice you dole out is right, and not leading people towards doing things that are potentially dangerous. If you truly knew your stuff, I'd suggest you wouldn't be doing this would you? Hence my advice; get a qualified electrician.
 
Last edited by a moderator:
Baldsparkies; I think the mistake you've made in post 10, is that you've virtually given the go ahead, then gone on to qualify your statement.
Should have gone the other way round.
The geezer will just see what he wants in your initial statement and ignore the rest!

this is about the only thing the plumber would of seen IMO.

Precisely the point I was making!

Apparently though, making g such a point makes us not very nice lol!
 

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