Electrical bods, help with MCBs and RCBOs!
Discussion
My shower is a 10.3kW shower. When I had it installed, the sparky that did it put in a 32A MCB into my consumer unit (MK Sentry.)
I knew at the time that this wasn't enough, that it needed to be 45A, but I just use the "1" heat mode on my shower and never the "2" mode, as that trips the MCB.
I've had enough of this, I'd like a fully functioning shower.
So, I went to B&Q yesterday and bought a 45A MCB, which looks like this:

Unfortunately, I didn't realise (as I didn't have the cover off my CU at the time) the MCB for the shower is actually an RCBO and looks like this:

I can't find anyone selling that particular type of RCBO (LN 6330, 32A, Type 2, 30mA) any more, all I can find are these 45A Type B Curve ones, whatever that means.
Can I use one of those in place of the existing one? The existing one just seems to have the live and neutral wiring going into it, I can't see any wires at the back like the white and blue ones on the photo of the existing one, but they could be hidden behind other wires.
Any ideas?
I knew at the time that this wasn't enough, that it needed to be 45A, but I just use the "1" heat mode on my shower and never the "2" mode, as that trips the MCB.
I've had enough of this, I'd like a fully functioning shower.
So, I went to B&Q yesterday and bought a 45A MCB, which looks like this:

Unfortunately, I didn't realise (as I didn't have the cover off my CU at the time) the MCB for the shower is actually an RCBO and looks like this:

I can't find anyone selling that particular type of RCBO (LN 6330, 32A, Type 2, 30mA) any more, all I can find are these 45A Type B Curve ones, whatever that means.
Can I use one of those in place of the existing one? The existing one just seems to have the live and neutral wiring going into it, I can't see any wires at the back like the white and blue ones on the photo of the existing one, but they could be hidden behind other wires.
Any ideas?
gazchap said:
My shower is a 10.3kW shower. When I had it installed, the sparky that did it put in a 32A MCB into my consumer unit (MK Sentry.)
I knew at the time that this wasn't enough, that it needed to be 45A, but I just use the "1" heat mode on my shower and never the "2" mode, as that trips the MCB.
Chap who fitted our shower got a bit shirty when we went for a 10.3kW (replacing something slightly less meaty) as it meant that he needed to fit heavier gauge wire as well - just over the threshold apparently - might be worth checking that yours is up to the job too.I knew at the time that this wasn't enough, that it needed to be 45A, but I just use the "1" heat mode on my shower and never the "2" mode, as that trips the MCB.
The Electrican that you used could not of been one as this is so basic, he could not of been a qualified. current= power/volts lets take your voltage is 240 at the consumer unit, some times this can vary, so 10,500/240 = 43.75 amps so yes your very right that you should have a 45amp Rcbo
There's no way he is Part P and also if you are not happy with him, report him.
Do not change the Rcbo yourself as how do you know how fast the Rcbo trips.
Remember under Part P it is a Crimanal offence to have some one who is not a competent person to do electrical work, especially in the Bathroom or a circuit supplying ie a shower.
You are looking for members who are either:
Napit
Neciec.
I am an industrial and Part P electrican if i made basic errors like this i would give my job up .
I see this all the time, customers only think of one thing PRICE, they do not seem to care who does there work for them.
I get so many people say to me that - they know of someone who can do the job that i have quouted for by about two thired cheaper.
There's no way he is Part P and also if you are not happy with him, report him.
Do not change the Rcbo yourself as how do you know how fast the Rcbo trips.
Remember under Part P it is a Crimanal offence to have some one who is not a competent person to do electrical work, especially in the Bathroom or a circuit supplying ie a shower.
You are looking for members who are either:
Napit
Neciec.
I am an industrial and Part P electrican if i made basic errors like this i would give my job up .
I see this all the time, customers only think of one thing PRICE, they do not seem to care who does there work for them.
I get so many people say to me that - they know of someone who can do the job that i have quouted for by about two thired cheaper.
Mr Pointy said:
What size is the cable from consumer unit to shower? If it's 6mm then do not change the breaker to a 45A as the current one is all that is protecting the cable from overheating. A 10Kw shower needs feeding by at least 10mm cable.
100% agree! I'm sorry, but best advice is not to touch it all yourself, get a registered electrician to do it for you. It looks like a 6mm cable, but hard to tell from the picture. It's not worth the risk if you are not 100% sure you know what you are doing.I don't mean offense, and we all like to do jobs ourselves, me included, but this is potentially very dangerous.
Griff Boy said:
Mr Pointy said:
What size is the cable from consumer unit to shower? If it's 6mm then do not change the breaker to a 45A as the current one is all that is protecting the cable from overheating. A 10Kw shower needs feeding by at least 10mm cable.
100% agree! I'm sorry, but best advice is not to touch it all yourself, get a registered electrician to do it for you. It looks like a 6mm cable, but hard to tell from the picture. It's not worth the risk if you are not 100% sure you know what you are doing.I don't mean offense, and we all like to do jobs ourselves, me included, but this is potentially very dangerous.
- erm no, think we'll have it done properly, thanks.Yer look what happened when they tried DIY electrical repairs at fujishima.
Lordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
Lordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
Mr GrimNasty said:
Yer look what happened when they tried DIY electrical repairs at fujishima.
Lordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
I have never seen anyone make up certificates, what do you do for a living? I see your profile is blank which seems be be quite common amongst the gobsLordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
tes on this site. I agree there is no need to read the op the part p riot act, but if he cannot source a simple rcbo then maybe he shouldn't be messing about in the consumer unit. A little knowledge is a dangerous thing, now be a gent and go fist yourself.cuprasparkuk said:
Remember under Part P it is a Crimanal offence to have some one who is not a competent person to do electrical work, especially in the Bathroom or a circuit supplying ie a shower
Utter b
ks.It's generally perfectly legal to do minor modifications to existing circuits yourself as long as they're not in a special location such as a bathroom or kitchen.
If the work involves things like new circuits or is in a 'special location' (bathroom, kitchen or garden) then providing building control are notified (and paid the appropriate fee) the work can be done perfectly legally by anyone. Of course the work still has to be to the regs and fully tested with documentation or building control probably won't sign it off. The various Part P domestic installer schemes just provide a mechanism for registered competent electricians to self certify their work and notify building control after the event.
chr15b said:
What about the none competent persons scheme via building control?
The snag here is that most building control officers say they can't test the installation and you have a get a Part P certified electrician to test and certify it. Then you can't get an electrician to do this as they won't certify work they haven't done.gazchap said:
Yeah, it's all going way over my head now so I'll get in a (proper) sparky.
The one that installed it was a recommendation from a friend, and I only dealt with said friend rather than the sparky. Bit silly, in retrospect!
That's the only safe route I'm afraid (leaving aside the legal aspect). You will have to make a choice though:The one that installed it was a recommendation from a friend, and I only dealt with said friend rather than the sparky. Bit silly, in retrospect!
1) Keep the 10kw shower & replace the existing 6mm cable with 10mm while upgrading the breaker to 45A. Depending on how the shower is installed this could mean retiling if the cable is buried in the wall. Could be messy & expensive.
2) Replace the 10Kw shower with an 8.5Kw one which will need a 40A breaker but which MAY be ok with 6mm cable depending on how long the run is & if it's not running under loft insulation for instance. Could be a cheaper solution, although you won't get such a good shower.
3) Replace the 10kw shower with a 7.5kw one which will not require a change to the 32A breaker or cable (according to the Triton website). Probably the cheapest solution & may be acceptable as it may be more than you are able to get at the moment with the 10kw shower on it's low setting.
It depends on the cable run really, & how much you have in the budget.
The cable was all added to the outside of the wall, in trunking, so no retiling or anything would be required.
The main reason I want to be able to use the higher setting on my shower is so that I can get higher water pressure for the same temperature, to have a comfortable shower in cold weather on the lower setting, the water pressure is pitiful.
I'll get a few quotes and see what the sparkies come back with.
Cheers for the help guys.
The main reason I want to be able to use the higher setting on my shower is so that I can get higher water pressure for the same temperature, to have a comfortable shower in cold weather on the lower setting, the water pressure is pitiful.
I'll get a few quotes and see what the sparkies come back with.
Cheers for the help guys.
jeebus said:
Mr GrimNasty said:
Yer look what happened when they tried DIY electrical repairs at fujishima.
Lordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
I have never seen anyone make up certificates, what do you do for a living? I see your profile is blank which seems be be quite common amongst the gobsLordy lordy. The OP is clearly far more intelligent than your average domestic electrician i.e. a dimwit school drop out with a god complex since his industry adopted protectionist practices under the fraudulent guise of safety. Clearly he can judge what needs doing. And don't mince on about insulation and earth resistances and continuity and ramp testing blah blah - most sparks never actually bother and make up the 'certificates'. Even the pro posting above warning of doom and jail can't even type or get things write (probably both).
tes on this site. I agree there is no need to read the op the part p riot act, but if he cannot source a simple rcbo then maybe he shouldn't be messing about in the consumer unit. A little knowledge is a dangerous thing, now be a gent and go fist yourself.Most domestic electricians thought they'd won the lottery when Part P was brought in, after bribery by the 'scheme providers' who make a killing out of selling their registration. And that is their only interest, money, not safety.
Most domestic electricians are thick and lazy, that's why they failed and ended up as a 'trade', sorry if that hits a nerve, but that's why they get so angry when you point out the truth.
I'd offer my fist to you, but I'd doubt you'd feel it whilst your talking.
And if people are going the building control route, remember to point out that the fee is inclusive of the BCO arranging and paying for the testing - they don't like to admit that.
Edited by Mr GrimNasty on Monday 21st March 12:39
Mr GrimNasty said:
And if people are going the building control route, remember to point out that the fee is inclusive of the BCO arranging and paying for the testing - they don't like to admit that.
There are a few letters and guidance notes from the former Office of The Deputy Prime Minister (who had responsibility for the Building Regulations at the time) available on t'internet which back this up if you have an awkward Local Authority. The main document is a circular letter sent to all local authorities in March 2006 which is quite clear:Circular Letter said:
Inspection, testing and BS 7671 certification
C.6 The ODPM has continued to receive hundreds of complaints and queries relating to the need for inspection, testing and BS 7671 certification of installations. Section 1 of the Approved Document has therefore been extensively revised to make it clearer what testing needs to be carried out and who should be expected to do so. The guidance makes it clear that only the person who carried out the installation can complete a BS 7671 installation certificate. It cannot be done by a third party.
C.7 Local authorities have no powers to ask householders or others who are not qualified to carry out testing and complete a BS 7671 electrical installation certificate at the householders’ expense. Where a local authority thinks that such testing is necessary in the circumstances to ensure that reasonable provision has been made the local authority must do this at its expense.
C.6 The ODPM has continued to receive hundreds of complaints and queries relating to the need for inspection, testing and BS 7671 certification of installations. Section 1 of the Approved Document has therefore been extensively revised to make it clearer what testing needs to be carried out and who should be expected to do so. The guidance makes it clear that only the person who carried out the installation can complete a BS 7671 installation certificate. It cannot be done by a third party.
C.7 Local authorities have no powers to ask householders or others who are not qualified to carry out testing and complete a BS 7671 electrical installation certificate at the householders’ expense. Where a local authority thinks that such testing is necessary in the circumstances to ensure that reasonable provision has been made the local authority must do this at its expense.
To clarify to the morons in this thread, if you do ever get away from your keyboard warriorism and decide to enter the real world, you should speak to some sparks before spouting b
ks.
Most sparks hate Part P we hate fannying around doing jobs that anyone with a half a brain cell could easily manage. As for school drop outs, what a crock of s
t - a minimum of 5 A*-C. I myself am a spark and attended a selective grammar school, passed the entrance exam with people a year above me and didn't get a GCSE result below a B.
I get f
king sick of hearing about how all sparks love Part P and we are all thieving b
ds. The reason our trade has some sort of professionalism, is due to the fact that not just any clown can start wiring houses, at least not legally.
/rant
Apologies for the thread hijack
ks.Most sparks hate Part P we hate fannying around doing jobs that anyone with a half a brain cell could easily manage. As for school drop outs, what a crock of s
t - a minimum of 5 A*-C. I myself am a spark and attended a selective grammar school, passed the entrance exam with people a year above me and didn't get a GCSE result below a B.I get f
king sick of hearing about how all sparks love Part P and we are all thieving b
ds. The reason our trade has some sort of professionalism, is due to the fact that not just any clown can start wiring houses, at least not legally./rant
Apologies for the thread hijack
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