Elec Shower Questions

[macrofeet]

Hi,

Currently replacing a Gainsborough 2000x which would be a 9.5kw(39.9amp) which was installed before i moved in prob when the house was built and worked fine for a few years after i moved in

it was setup in the following way

Separate fusebox(CU) from lights and power (1990's mem), with a single 30amp cartridge fuse,
No rcd,
Pull switch in bathroom(unknown rating)

Wiring is approx 9-10 meters long 6mm+, 2core & earth, via trunking and loft

I went to b&q looking for a 7.5kw(31.5amp) shower

however they only had 8.5kw(35.7amp)+ for sale

i realise i will need to get the CU replaced at some point if the creda 8.5kw i got does not blow the fuse straightaway

Questions

If i fit a 40amp rcd is it going to trip out constantly ?

if i get a 40amp mcb(CU) fitted will i need to replace the wiring with 10mm

thanks guys

 

[rebuke]

Firstly, note that in England or Wales changing the protective device is notifiable to your LABC before doing the work under Part P of the building regs...

The current rating on an RCD is a safe maximum load, a standard RCD has no overcurrent protection, so you would still need an MCB. You can get RCBOs, which combine the two devices.

You should find the RCD part only trips if there is a fault. As for the current - when I moved in to my place the previous owners had a 9.5kW shower on a 32A MCB, and that never tripped in use, essentially because although it was over the limit, it wasn't far over, so unless it was used for a long period of time the breaker wouldn't trip as it relies on the thermal part not the magnetic part.

With 6mm, you are limited to around 30A off hand (it depends on length and installation method) - if I were you I would replace the 6mm with 10mm, then put a 9.5kW shower on, there's no point putting anything less in - you will notice the lack of power. Given that the work would be notifiable, you may find it cheaper/easier just to get a qualified spark in to do the job...

 

[macrofeet]

After replacing the wiring from the shower to the rcd i'd now like to replace the shower CU to 40amp

fitting this is not a problem looks like a simple job however

As i cant really afford someone to come fix it for me and i'd like to do it my self if i am able

1/ i'm on an electric meter if i let the credit run out and trip off, am i safe to replace the stand alone CU for the shower or how can i properly switch of the power to my house ?

2/ would i need to get the wiring from the meter to the CU replaced

 

[PrenticeBoyofDerry]

We will assume you live in England or Wales.
This work if done by yourself (DIY) is notifiable to building controls, this is a legal requirement and a fee will need to be paid on application, and work notified prior to work started.
This link will help you understand this.

//www.diynot.com/wiki/electrics:part_p:diy_electrical_work_and_the_law

If it's a simple case of saving money, the likelihood is if you employed an electrician that is registered with a scheme provider it will work out cheaper and safer, than taking this work on yourself and doing it legally.
The electrician will be able to sign the work off and should be able source the correct equipement at trade discounted prices.
Those saving you the notification fee and saving cost on materials and your not breaking the law.

 

[mfarrow]

After replacing the wiring from the shower to the rcd

What with? 10mm² I'll assume for now

1/ i'm on an electric meter if i let the credit run out and trip off, am i safe to replace the stand alone CU for the shower or how can i properly switch of the power to my house ?

Probably, but you'll need to check for dead at the incoming side of the main switch.

2/ would i need to get the wiring from the meter to the CU replaced

Probably not, the meter tails should be man enough. Can you post a pic?

You'll need something like
http://www.screwfix.com/prods/87896 and
http://www.screwfix.com/prods/44720

Don't forget to inform the LABC. Otherwise if they find out, you will have to pay the fee anyway and if the work is wrong then you may be asked to put it right.

 

[mikhailfaradayski]

After replacing the wiring from the shower to the rcd i'd now like to replace the shower CU to 40amp

why? You say you currently have a 9.5kW shower running off a 30 A fuse. You are changing to a lower rating, which you already know will cause a lower current.

fitting this is not a problem looks like a simple job however

simple, but illegal and dangerous if you don't do it correctly.

As i cant really afford someone to come fix it for me and i'd like to do it my self if i am able

Can you afford the £5000 fine that you may be liable for if it comes to light that you have carried out illegal work?

1/ i'm on an electric meter if i let the credit run out and trip off, am i safe to replace the stand alone CU for the shower or how can i properly switch of the power to my house ?

Im concerned that you feel changing the characteristics of a CU is easy when you are not sure about safe isolation. Maybe a bit dramatic, but one mistake can equal heart attack/burns/fire/death (merry christmas )

2/ would i need to get the wiring from the meter to the CU replaced

Bite the bullet, get an electrician to do it safely, legally and you give the design headache to him and get a warranty in return.
The notification fees alone for this job make it expensive as a DIY project.

 

[macrofeet]

why? You say you currently have a 9.5kW shower running off a 30 A fuse. You are changing to a lower rating, which you already know will cause a lower current.

sorry i should have said "after the 3core 6mm2 has been replaced" i have not yet replaced the est 6mm2, 3 core cable as i would need the power off from the meter first

so far i've only installed a stand alone rcd shower side of the fuse and replaced the shower unit this was a long time ago

The orginal shower when i moved in over 5 years ago was 9.5kw i did not realise anything was incorrectly installed, untill the fuse blew after about 6 months after this, i changed out the shower with an 8.5kw which has only been used mid setting on luke warm the fuse is not getting hot and has not blown since, i would have got a correct 7.0kw but it would be quite a weak shower, they are harder to buy once i get the wire and CU sorted it will work out better.

simple, but illegal and dangerous if you don't do it correctly.

i'm trying to get it done correctly, my first post was a year ago and i do not rush into things until i am sure, i am no electrician but i am however qualified in IT and worked for many years in IT before i went into in stone masonry drystone walling etc i have built and wired up arcade cabinets and networked offices and built like over 1000 computers and laptops, i don't think it would be a problem for me to physically replace the CU but need to be sure i'm not missing somthing.

Can you afford the £5000 fine that you may be liable for if it comes to light that you have carried out illegal work?

So far this year i have made £4000 from april working full time which just about coverd my bills, recently its been -4 outside and i'm thinking a hot shower would be nice after work all day instead of a luke warm shower as i cant actually afford to heat my house apart from having the gas oven on and also i am £7000 in dept and i have currently no work for the new year no it is not going to be a merry christmas for me but i'd rather work then sponge off the doll even tho i'd get more money

Im concerned that you feel changing the characteristics of a CU is easy when you are not sure about safe isolation. Maybe a bit dramatic, but one mistake can equal heart attack/burns/fire/death

The physical work seems quite simple, i have not done this before, but i am sure i could do the wiring work needed, my friends dad is more than qualified to do the work however it would be a bit much to ask him to do all the work for me for free i might get all the needed materials, run the wiring from shower and then just get him to replace the cu one day[/quote]

 

[Taylortwocities]

1/ i'm on an electric meter if i let the credit run out and trip off, am i safe to replace the stand alone CU for the shower

Never, ever, trust anything like this!!!.

The supply needs to be properly, safely isolated or you put yourself in the way of serious danger.
Get a competent electrician if you do not know how to do that.

 

[macrofeet]

i cant replace the CU with out opening the meter as the only way to isolate the cu which does not involve opening the meter and removing the fuse is unsafe ?


[/quote]

 

[wingcoax]

Don't even think about opening the meter. As you have been told, get hold of a competent electrician to do the job. You will save money and still be legal.

 

[mikhailfaradayski]

why? You say you currently have a 9.5kW shower running off a 30 A fuse. You are changing to a lower rating, which you already know will cause a lower current.

sorry i should have said "after the 3core 6mm2 has been replaced" i have not yet replaced the est 6mm2, 3 core cable as i would need the power off from the meter first

Im now confused as to what you / had originally / have done since / what you have got now

so far i've only installed a stand alone rcd shower side of the fuse and replaced the shower unit this was a long time ago

The orginal shower when i moved in over 5 years ago was 9.5kw i did not realise anything was incorrectly installed, untill the fuse blew after about 6 months after this, i changed out the shower with an 8.5kw which has only been used mid setting on luke warm the fuse is not getting hot and has not blown since, i would have got a correct 7.0kw but it would be quite a weak shower, they are harder to buy once i get the wire and CU sorted it will work out better.

simple, but illegal and dangerous if you don't do it correctly.

i'm trying to get it done correctly, my first post was a year ago and i do not rush into things until i am sure, i am no electrician but i am however qualified in IT and worked for many years in IT before i went into in stone masonry drystone walling etc i have built and wired up arcade cabinets and networked offices and built like over 1000 computers and laptops, i don't think it would be a problem for me to physically replace the CU but need to be sure i'm not missing somthing.

Can you afford the £5000 fine that you may be liable for if it comes to light that you have carried out illegal work?

So far this year i have made £4000 from april working full time which just about coverd my bills, recently its been -4 outside and i'm thinking a hot shower would be nice after work all day instead of a luke warm shower as i cant actually afford to heat my house apart from having the gas oven on and also i am £7000 in dept and i have currently no work for the new year no it is not going to be a merry christmas for me but i'd rather work then sponge off the doll even tho i'd get more money

Thats unfortunate and i sympathise, however since you are an intelligent type, think through the question. Its no point whinging about how destitute you are, it makes no difference. You could still be liable for a £5000 fine if it all goes ti ts up, can you afford that? Do you want to put yourself at risk? Do you know how much your council charge for pre-work notification? Do you know of their requirements?

Im concerned that you feel changing the characteristics of a CU is easy when you are not sure about safe isolation. Maybe a bit dramatic, but one mistake can equal heart attack/burns/fire/death

The physical work seems quite simple,

it is

i have not done this before,

i think building PCs is easy, done a few myself. I think plugging cat5 leads into panels is easy, but without any direct experience, i think i would be nervous trying to install a newtwork of 5000 terminals into a hospital or similar by myself where the only information resources i have are from strangers on an internet forum. (BTW, what test equipment do you have?)

but i am sure i could do the wiring work needed, my friends dad is more than qualified

Qualification or competence isnt really the issue here. It is notification of the job, talk to your friends dad, ask him how to deal with notification and how much it costs. If he cannot answer that easily, then the chance is he cannot do it without dealing with LABC

to do the work however it would be a bit much to ask him to do all the work for me for free i might get all the needed materials, run the wiring from shower and then just get him to replace the cu one day

Talk to an Electrician about your plans, watch his expression change to one of dismay and disapproval.

 

[ban-all-sheds]

Can you afford the £5000 fine that you may be liable for if it comes to light that you have carried out illegal work?

Oh come on - there are reasonably-to-be expected implications of not notifying work when you should, but a £5,000 fine is not one of them.

 

[mikhailfaradayski]

Can you afford the £5000 fine that you may be liable for if it comes to light that you have carried out illegal work?

Oh come on - there are reasonably-to-be expected implications of not notifying work when you should, but a £5,000 fine is not one of them.

i know its unlikely, but im just telling the OP what might happen.

If you feel comfortable with it, why don't you tell the OP to ignore the potential consequences.

 

[ban-all-sheds]

i know its unlikely, but im just telling the OP what might happen.

No - you're scaremongering to make a point. It is so unlikely that it can be disregarded.

If you feel comfortable with it, why don't you tell the OP to ignore the potential consequences.

Nobody can tell him to do that.

 

[mikhailfaradayski]

i know its unlikely, but im just telling the OP what might happen.

No - you're scaremongering to make a point.

no i'm not

It is so unlikely that it can be disregarded.

is that your advice to the OP?

If you feel comfortable with it, why don't you tell the OP to ignore the potential consequences.

Nobody can tell him to do that.

why not?