Replacing 8.5kw with 9.5kW shower

damoz

Need advice. replacing a shower - want to use a 9.5kw in place of the current 8.5kw one (which has packed up).

The RCD is 30mA. The MCB is 63A i believe. Is this sufficient for 9.5kw shower?

Also, i believe i need 10mm cabling - how do i actually know what it is (measure!?). Have pics if that would help.

tomdempsey200

best advice

get a competent electricuan

2011

I'm with tomdempsey200 on this one.A number of things to consider:The MCB is not suitable for a 9.5kW load. I assume it is "type B" ?This should be selected on the basis of the design current.The protective device should also provide discrimination with the main switch fuse in the distribution board, a 63A MCB is not likley to do this (in a domestic installation). Are you sure that it is an MCB?More information would be required to size the cable correctly. A 10 sq. mm T+E may well be suitable but this can not be verified without knowing lenght of run, ambient conditions etc.. the final circuit arrangement must pass earth fault loop impedance test, not exceed maximum permissable volt drop etc..

damoz

Some images to help - i assume the 63A is the MCB. The manual says minimum 80A - make sense?


Looks like ill need an electrician and a plumber to install this maybe better off sticking with a 8.5kw.

tomdempsey200

most of the board here are rated 63amp

that 80/100 is a UK spec but is better suited to the shower loads

2011

To me the first picture shows a 40A B type RCBO with 30mA current imbalance trip.
The last photo shows a switch fuse which most likely contains a 63A fuse.

tomdempsey200

yes 40amp rcbo...

63amp(main ocpd) board

i meant that the basic UK domestic supply is better suited to showers than the 63amp/12kva we use here

zega

That 9.5kw shower will pull about 41amps.You have a 40amp breaker.

damoz

zega wrote: »

That 9.5kw shower will pull about 41amps.You have a 40amp breaker.

... so needs to be changed? To what? Sorry, it may need to spelt out for me

tomdempsey200

damoz wrote: »

... so needs to be changed? To what? Sorry, it may need to spelt out for me

you can't just swop it out

it's providing overcurrent protection for the cable

that's why you need a competent electrician on the job

or you'll be going round here in circles
with questions and answers

damoz

I intend to get an electrician - just wondering whats entailed, and what it will cost. As i stated, i still have the option to revert to 8.5kW shower.

zega

damoz wrote: »

I intend to get an electrician - just wondering whats entailed, and what it will cost. As i stated, i still have the option to revert to 8.5kW shower.

Get an 8.5kw shower,what that lad above me is saying is that the cables in the walls might not be big enough to power a 9.5kw shower safely.

There's a reason certain size breakers are used,its to protect the cable from carrying more current than its designed for,So thats why you cant just stick on a 50amp breaker(for example),hence why you'll need an electrician

solargain

+ 1

dodzy

tomdempsey200 wrote: »

best advice

get a competent electricuan

tomdempsey200 wrote: »

that's why you need a competent electrician on the job

or you'll be going round here in circles
with questions and answers

Super assistance given there. Would you not just answer the OPs questions ? I think they know they need a sparks, but it still wouldn't hurt to be a little more helpful.

2011

dodzy wrote: »

Super assistance given there. Would you not just answer the OPs questions ? I think they know they need a sparks, but it still wouldn't hurt to be a little more helpful.

Cool your jets.

The OPs questions have been answered so far as is possible.
Some sound advice has been given.

tomdempsey200 is trying to avoid a situation where the OP takes on something that is beyond his/her capabilities.
The fact that 230V is potentially lethal is often forgotten by DIY people.

dodzy

2011 wrote: »

Cool your jets.

The OPs questions have been answered so far as is possible.
Some sound advice has been given.

tomdempsey200 is trying to avoid a situation where the OP takes on something that is beyond his/her capabilities.
The fact that 230V is potentially lethal is often forgotten by DIY people.

Apologies if my post was offensive. It's just annoying when someone chimes in here with the same ole "get a qualified whatever". Case and point, the first response to the OPs question, #2. Now, comparing this to your first response, #3, basically says the same thing, but you provided some info also. Big difference.

This place is a great source for advice on bloody everything, but just once, I'd like to see similar posts answered with something other than that same predictable line. By all means refer to a qualified professional, but at least go some way towards answering the questions.

2011

dodzy wrote: »

By all means refer to a qualified professional, but at least go some way towards answering the questions.

I think that this has been achieved here.

The aim of this forum is not to turn laypersons into the equivalent of qualified electricians. Although it can assist some to deal with the fundamentals and help people to speak the "electrical language" it is important to inform people when something is beyond them.

You honestly would not believe some of the things that I have seen people attempt over the years. A little knowlage can kill!

Unfortunately most electrical items in the home will "work" once they have a phase and neutral connected to them (even when the polarity is reversed). This can mislead people into thinking that the devices are correctly wired and will work safely.

hufpc8w3adnk65

dodzy wrote: »

Apologies if my post was offensive. It's just annoying when someone chimes in here with the same ole "get a qualified whatever". Case and point, the first response to the OPs question, #2. Now, comparing this to your first response, #3, basically says the same thing, but you provided some info also. Big difference.

This place is a great source for advice on bloody everything, but just once, I'd like to see similar posts answered with something other than that same predictable line. By all means refer to a qualified professional, but at least go some way towards answering the questions.

Yes this place is great for advice on gardening, cycling, football streams etc etc etc! There's a reason we spend 4 years serving our time and why it's now illegal for non registered electricians too do a lot of works! The poster has shown in his first post hes not competent enough too carry out this job and by us telling him here how too do it could result in serious injury or worse!

dodzy

MrMac84 wrote: »

Yes this place is great for advice on gardening, cycling, football streams etc etc etc! There's a reason we spend 4 years serving our time and why it's now illegal for non registered electricians too do a lot of works! The poster has shown in his first post hes not competent enough too carry out this job and by us telling him here how too do it could result in serious injury or worse!

I think that the OP gets your point regarding his/her incompetence at this stage. As you can see below, they had indicated that they were "intending on getting an electrician". I think that your post above highlights what was contained in my earlier post, perfectly. Thankfully, 2011 has answered the OPs questions combined with the recommendation of seeking RECI help (that's all that was requested), as it's obvious your intention was to do nothing of the sort.

damoz wrote: »

I intend to get an electrician - just wondering whats entailed, and what it will cost. As i stated, i still have the option to revert to 8.5kW shower.

And FWIW, I've seen work carried out by more than one "qualified" electrician. "Shoddy" would be an understatement, so don't tell me that just because someone is registered, quality & safe work is a guarantee.

markad1

MrMac84 wrote: »

Yes this place is great for advice on gardening, cycling, football streams etc etc etc! There's a reason we spend 4 years serving our time and why it's now illegal for non registered electricians too do a lot of works! The poster has shown in his first post hes not competent enough too carry out this job and by us telling him here how too do it could result in serious injury or worse!

It was 5 years when i served my time .....your either
a: young and it's changed since i done it or
b: your old and your memory is gone

only teasing you MrMac

2011

dodzy wrote: »

And FWIW, I've seen work carried out by more than one "qualified" electrician. "Shoddy" would be an understatement, so don't tell me that just because someone is registered, quality & safe work is a guarantee.

Unfortunately it is a fact that some electricians (including those that are registered) have produced some horrendous work over the years particulary during boom times. However the solution is not to let just anybody "have a go".

This is something that CER has being trying to address. Tough new legislation was brought in last year to deal with offenders, I have read about prosecutions already. Even when an inspector from (for example) RECI deems work to be of sufficient standard there is now the option to take the complaint to another level by reporting it to CER. I have been very disappointed with RECI inspections in the past. Hopefully in time the poor standards of workmanship that we have seen from some electricians will be a distant memory.

tomdempsey200

what is the current-carrying capacity of 6sq T+E in domestic installs?

shower on ground floor

shower on first floor

hufpc8w3adnk65

markad1 wrote: »

It was 5 years when i served my time .....your either
a: young and it's changed since i done it or
b: your old and your memory is gone

only teasing you MrMac

I done phase 2 15 years ago

Bruthal

tomdempsey200 wrote: »

what is the current-carrying capacity of 6sq T+E in domestic installs?

shower on ground floor

shower on first floor

The actual current capacity of a cable would be the same no matter how long the cable is. Its all about the volt drop.

tomdempsey200

Bruthal wrote: »

The actual current capacity of a cable would be the same no matter how long the cable is. Its all about the volt drop.

yes... I mean 'install methods' not length of run obviously

what are the capacities ballpark for different domestic installs

bungalow,ground floor,first floor locations

damoz

kinda sorry i asked now. I just wanted some advice, as the professional i had to put in the shower was not clued in (him been a plumber and all). So. now i will have to get both an electrician and a plumber. Think ill just go back and get the 8.5kw and save the time, money and hassle. Cant for the life of me get an electrician who has time of day for a small job like this...

Sleeper12

You do need a good electrictian on this one. I'm guessing you are going to pay around €200 to get him / Her to replace 6mm with 10mm cable, swap the showers (price of shower not included) & change pull cord switch. The rcbo I think you are stuck with. I think you need a 45amp rcbo but they only come in 40amp. As far as I know this means it might trip every now & then. I'd be more worried about cable size. 6mm suits up to 9kw on a max of 15 meter run (I think). If you had a 16 meter or longer run you would need 10mm even for 8.5kw

2011

tpmcompany1 wrote: »

I think you need a 45amp rcbo but they only come in 40amp. As far as I know this means it might trip every now & then.

Believe it or not I had a 32A RCBO on a 9.5kW shower in my home for years and it never tripped. If you look at the fusing characteristics you will see why.

tomdempsey200

2011 wrote: »

Believe it or not I had a 32A RCBO on a 9.5kW shower in my home for years and it never tripped. If you look at the fusing characteristics you will see why.

yes

but it's a breach of wiring rules all the same

frankmul

zega wrote: »

That 9.5kw shower will pull about 41amps.You have a 40amp breaker.

2011 pointed out in a thread before that a shower rated at 9.5 kW /240v is only a 9.1 kW shower here at 230 volts. In one of the shower manuals. Current works out just below 40 amps. 40 amp rcbo should be ok then.
The cable would be the weak point. Needs to be sized correctly.

tomdempsey200

frankmul wrote: »

2011 pointed out in a thread before that a shower rated at 9.5 kW /240v is only a 9.1 kW shower here at 230 volts. In one of the shower manuals. Current works out just below 40 amps. 40 amp rcbo should be ok then.
The cable would be the weak point. Needs to be sized correctly.

they're usually marked on the box time

230 and 240 ratings

maybe it's a 230/9.5

Sleeper12

Triton showers sold in Ireland are boxed & labled for Ireland (Unlike Mira showers). So when you see9.5KW on a triton T90Z box it is rated for ireland 230v & not 240v UK. So you are back to needind greater than 40amp rcbo. Problem? you cant get 45 amp. So you make do with 40amp & it may trip a few times per year or it might not.

Cable size is the most important thing here. You need 10mm for 9KW or over. Triton are now saying on their boxes they recomend 10mm even on 8.5KW showers. Although you don't need 10mm on 8.5kw anyone putting in a shower from scratch should use 10mm cable. This future will proof the install & the homeowner can change the shower in years to come to 9.5KW

Again a good electrician is needed & with all tradesmen coming into your house ask to see his insurance cert. I have seen an electrician installing a shower & drilled into a pipe. He packed his bags & left with the slowly flooding! On the dole & no insurance!

2011

A 40A B type RCBO will not nuisance trip when feeding a 9.5kW shower due to the fusing characteristics of the device. At 230VAC it is drawing less than 42 amps which is only fractionally above the protective device rating, so no problem for a B type device.

Have a look at the graph shown on page 1 on this link:

http://www05.abb.com/global/scot/scot209.nsf/veritydisplay/b4f98ecc257a2a6c482579050006afb2/$file/1SXE420001L0202_092011_LP.pdf

2011

tomdempsey200 wrote: »

yes

but it's a breach of wiring rules all the same

Correct, but a 40A MCB protecting a load that draws fractionaly over 41A is not going to cause an electrical problem.
I take your point though, it is againt ET101 as the design current exceeds the rating of the protective device.

tomdempsey200

tomdempsey200 wrote: »

yes... I mean 'install methods' not length of run obviously

what are the capacities ballpark for different domestic installs

bungalow,ground floor,first floor locations

what is the answer to this

tomdempsey200

half the homes in the country were wired in 6sq on B40s

I'm not sure that it complies with wiring rules at all regardless of shower rating

2011

tomdempsey200 wrote: »

half the homes in the country were wired in 6sq on B40s

I'm not sure that it complies with wiring rules at all regardless of shower rating

A few things to consider:

1) I would think that if you were to measure the current drawn by an instantaneous shower that has 9.5kW on the name plate you will find that in reality it draws less than 40A. Therefore I think that you could argue that you have verified that the design current is less than the rating of the protective device, so it fully complies with ET101.

2) A 6sq. mm cable in reality can take the full load current of 8.5 and 9.5kW loads. However the designer/electrician needs to ensure that the volt drop and earth fault loop impedance (EFLI) values are not exceeded. This is generally dependant on the length of run.

3) As the size of the MCB (or RCBO) rating is reduced then the threshold for the EFLI value increases. This applies once the protective device type remains constant, so for domestic this would be a B Type. So what does this mean? It means that if a 40A MCB or RCBO is used then a higher EFLI value is acceptable than if a 45A protective device was used. This means that a smaller cable size may be selected in some cases.

4) There is the option of installing a RCD and a 45A MCB. These MCBs are a little harder to source, but it is possible.


5) A 6 sq. T+E and a 40A MCB/ RCBO is the perfect combination for most 8.5kW showers in the country. The issue is more for the 9.5 kW units.

tomdempsey200

2011 wrote: »

A few things to consider:

1) Therefore I think that you could argue that you have verified that the design current is less than the rating of the protective device, so it fully complies with ET101.

you've left out one detail... which was my query

design current and rating of protective device must be lower than cable ccc

2011

tomdempsey200 wrote: »

you've left out one detail... which was my query

design current and rating of protective device must be lower than cable ccc

No, I didn't. See point 2:

2) A 6sq. mm cable in reality can take the full load current of 8.5 and 9.5kW loads. However the designer/electrician needs to ensure that the volt drop and earth fault loop impedance (EFLI) values are not exceeded. This is generally dependant on the length of run.

2011

ET101:2008
Tables A52-F1 and A52-F2, PVC insulated cables with copper conductors, (1 phase) installation methods B1, C, D, and E are all shown to have current carrying capacities in excess of 40A despite the fact that the reference ambient temperature is high (30DegC).

The current carrying capacities for a 10 sq. PVC insulated cable with copper conductors in the same tables ranges from 43 to 70A depending on the method of installation.

Obviously a number of factors need to be taken into account when cable sizing, such as method of installation.

Sleeper12

2011 wrote: »

No, I didn't. See point 2:

Can I just say a normal householder asked a reasonably simple question (with photos no less) & the answers got more & more complex as the thread continues. Is this thread to try answer his questions in a way he might understand or is it about egos? Op must be more confused now than before he asked some simple questions.....

tomdempsey200

tpmcompany1 wrote: »

Can I just say a normal householder asked a reasonably simple question (with photos no less) & the answers got more & more complex as the thread continues. Is this thread to try answer his questions in a way he might understand or is it about egos? Op must be more confused now than before he asked some simple questions.....

well yes, but he hasn't provided basic information like cable size or even a photo of the cable



so what useful advice can he be given?


he may attempt something without considering all the variables and hazards

Sleeper12

tomdempsey200 wrote: »

well yes, but he hasn't provided basic information like cable size or even a photo of the cable



so what useful advice can he be given?


he may attempt something without considering all the variables and hazards

Very simple advice. Stick to 8.5kw shower & let a plumber or electrician swap it for around €100 or change to 10mm cable for 9.5kw. For around €250. Give or take €50. I guarantee he couldn't follow the last few posts. I'm in the business & I'm finding it hard.
Basic advice on this is get a good electrician if you want 9.5kw.
No one even bothered to tell him that a 40amp pull cord switch won't suit long term.
That's all he needs. Simple answers

2011

tpmcompany1 wrote: »

Can I just say a normal householder asked a reasonably simple question (with photos no less) & the answers got more & more complex as the thread continues.

Unfortunately in life simple answers do not necessarily follow simple questions.
"Why is the sky blue?" springs to mind

In this case a very simple answer (and possibly the best for the OP) was provided in post #2

Is this thread to try answer his questions in a way he might understand or is it about egos? Op must be more confused now than before he asked some simple questions.....

You are ignoring the fact that this thread was also dealing with questions asked by electricians.


However I think that a layperson reading this thread would conclude:

1) That swapping out a 8.5kW shower for a 9.5kW shower will most likely be costly.

2) Will require the services of a professional electrician

3) Will most likely involve replacing the cable.

4) It may be far more cost effective to replace the existing unit with one of the same rating.

5) It is not possible to know exactly what is required without carrying out a survey first.

6) There is a reason that it takes 4 years to qualify as an electrician and the work can be technical in nature.

7) Electricity can kill, don't muck around with it if you don't know exactly what you are doing.

tomdempsey200

2011 wrote: »

5) It is not possible to know exactly what is required without carrying out a survey first.

correct

who knows without taking a look whether the 'installation' is suitable for additional loading


tpmcompany1 has overlooked this in the rush to simple answers, which may mislead the op further

Bruthal

frankmul wrote: »

2011 pointed out in a thread before that a shower rated at 9.5 kW /240v is only a 9.1 kW shower here at 230 volts. In one of the shower manuals. Current works out just below 40 amps. 40 amp rcbo should be ok then.

A 9.5kw shower at 240v is actually 8.7kw at 230v.

It has all been mentioned before a few times.

tomdempsey200

Bruthal wrote: »

A 9.5kw shower at 240v is actually 8.7kw at 230v.

It has all been mentioned before a few times.

i think the UK has gone 230v ...in theory anyhow

Sleeper12

2011 wrote: »

Unfortunately in life simple answers do not necessarily follow simple questions.
"Why is the sky blue?" springs to mind

In this case a very simple answer (and possibly the best for the OP) was provided in post #2



You are ignoring the fact that this thread was also dealing with questions asked by electricians.


However I think that a layperson reading this thread would conclude:

1) That swapping out a 8.5kW shower for a 9.5kW shower will most likely be costly.

2) Will require the services of a professional electrician

3) Will most likely involve replacing the cable.

4) It may be far more cost effective to replace the existing unit with one of the same rating.

5) It is not possible to know exactly what is required without carrying out a survey first.

6) There is a reason that it takes 4 years to qualify as an electrician and the work can be technical in nature.

7) Electricity can kill, don't muck around with it if you don't know exactly what you are doing.

If you had posted this answer 4 pages ago op might not have been so confused.
Op here is your answer. Please ignore all the rest!

tomdempsey200

tpmcompany1 wrote: »

If you had posted this answer 4 pages ago op might not have been so confused.
Op here is your answer. Please ignore all the rest!

including yours..

Bruthal

tpmcompany1 wrote: »

Basic advice on this is get a good electrician if you want 9.5kw.
No one even bothered to tell him that a 40amp pull cord switch won't suit long term.

A 9.5kw shower is likely going to draw marginally under 40 amps in real life. So a 40 amp pull chord not doing the job long term will be due to factors other than being overloaded.

That's all he needs. Simple answers

Very little in life seems to have simple answers.

Bruthal

tpmcompany1 wrote: »

If you had posted this answer 4 pages ago op might not have been so confused.
Op here is your answer. Please ignore all the rest!

We can have 2 post threads from now on, now that your here:)