Discuss Diversity factor on rewire in the DIY Electrical Advice area at ElectriciansForums.net

Percyprod

-
Esteemed
Reaction score
226
I'm going to rewire my house, and was wondering if it's ok to have 2 shower circuits as well as cooker, sockets and lights off 1 cu, or would it be better to have 1 of the showers on a separate cu, because of the available water pressure the 2 showers are never on together.
 
I'm going to rewire my house, and was wondering if it's ok to have 2 shower circuits as well as cooker, sockets and lights off 1 cu, or would it be better to have 1 of the showers on a separate cu, because of the available water pressure the 2 showers are never on together.
How are you intending to limit the usage of the showers to 1 at a time? if you go the route you have outlined all on the same CU is fine, You will of course need to apply diversity to the whole installation not just the showers and cooker.
 
I'll use the same method I do now - " I'm having a shower, don't run any water!". I was just wondering what usual practice was, it's not a big house, and only 3 people. I appreciate diversity is applied to the whole installation.
 
Contractor which allows only one shower to be used at a time. Also what size is the mainDNO fuse?
 
Interesting point. Can't be bothered fitting contactor, no need. Was told by engineer that 80 amp is big enough fuse for cut-out, as very few properties need 100 amp. Any way, I fitted 100 amp fuse when I fitted meter. His arguement was that if you fit 100 amp it could get too hot if you are pulling 100 amps. My reasoning is that an 80 amp will get even hotter, as it will take the 100 amps for quite some time. Any way cut out is 100 amp.
 
Could always add a booster for your main water?

Not sure why you would want 2 electric showers if your only ever going to use one at a time?
Diversity doesn't apply to showers either so if your using 10.5kw showers and both are on at the same time your going to be drawing 90amps so your Your not far away from your 100amps cut out.
 
Long story, but basically had extension build, and lost part of one bedroom. Decided to make that into another toilet, and as couldn't fit a bath fitted a shower. Like I say, never used together, certainly not going to pay for pump. Why should we ask the Big Chocolate ourangatan?
 
Well, non scheme member doing rewire in England - surely you're going to notify BCO before you start so they can inspect at every stage?
Judging by previos posts I doubt it.
 
Well you have been given the correct answer that there is no diversity allowed with showers.
However I did a cu change a while back at busy holiday cottage which had quite happily been running 3 x 8.5kW showers plus all the normal appliances for the last 10-15 years through a 60A fuse. The main shower now fed by a combi
Isn't it only a DNO network planner who can decide on the size fuse you have? What is the rating of your meter? I think you may have misunderstood the 100A fuse issue, the fuse carriers were overheating before the fuse would blow therefore whenever seen (this is what happens locally) they are reduced to 80/60A so that the fuse blows before the carrier gets too hot. What size supply does your supply agreement state? Locally our agreements are for 15kVA so an 80A fuse is the most suitable.
 
Seems like quite a lot of work for a DIYer, how do you intend to test and certify it?
Seems odd every time that question is asked of a DIYer it goes all quiet
 
Seems odd every time that question is asked of a DIYer it goes all quiet
I actually got a call from someone on Wednesday asking if I could test and certify 2 semi detached houses that the owner had wired, saying his electrician had let him down and he'd ran out of time, but as he had some knowledge 'of electrics' he's done it himself, including all 2nd fixing. I don't know about anyone elses opinion but I wont be doing it there is no chance i would sign my name under a full rewire by a DIY expert
 
Very often DIY jobs are done to a higher standard than those done by so called proffesionals, so let's not go down that road. Any way, I suppose that means none of you would do any work on your car or van, as you're not 'a professional'? Actually what I meant was is it normal practice to fit 2 showers in a cu. I know there is no diversity on their use. As stated they won't be used together. And Mathewd29, if you don't know how to wire and test a shower it's not up to me to tell you!
 
I am not having a go at you, and I disagree with your statement about DIY work being better, maybe it is in a very rare case, but more often it is dangerois and potentially deadly. I am not a so called professional, in fact I am a professional.
 
My comments wern't aimed at you personally Matthew, I don't doubt you professionalism, nor for electrical work either, but in general a lot of diy do a very good job, whatever it is, and some professionals don't. Perhaps I gave the impression I think most diyers are better, not what I meant. Like I say, many motorists do work on their cars, which is possibly potentially more dangerous than doing some wiring, and they have no mechanical training, but they do as good a job as a garage would. I just don't agree that unless you have the necessary electrical ticket you can't do a safe job that complies with the regs, other than not being signed off.
 
You don't need a ticket, you need to be competent. Your original question proves a lack of competence.

There is a line when dipping into other areas of expertise. I'm sure many people could change the oil and filters in their car without being mechanics but wouldn't try and change a gearbox.

They would likely struggle to do an MOT too without having the right paperwork to back them up!

And Mathewd29, if you don't know how to wire and test a shower it's not up to me to tell you!

Why should it be up to us to tell you how to do it!
 
Last edited:
No, but a lot of people would do work on the brakes, suspension etc. I am perfectly competent, it was just a simple question on what other people do. All work I do is perfectly safe. If it is not, then as I have worked to the regs then you are saying they are wrong.
 
No, but a lot of people would do work on the brakes, suspension etc. I am perfectly competent, it was just a simple question on what other people do. All work I do is perfectly safe. If it is not, then as I have worked to the regs then you are saying they are wrong.

At no point did I insinuate the regulations were wrong.

In my opinion you answered your own question in your original post:

because of the available water pressure the 2 showers are never on together.

If this is the case then I see no reason not to have them both on the same board. At the very least I would put them on different RCDs (if it's a split load board), to minimise potential overheating issues as the RCDs tend to be rated at 63/80A. The only time a problem may arise is if/when you come to sell the house.

I'll add that when I was serving my time we completed an EICR on a 12 bed guesthouse (with attached 3 bed owners accomodation). The guesthouse was supplied with a standard "100A" domestic supply. The install was spread over 3 or 4 boards to accommodate various extensions/renovations over the years. There was in total 13 electric showers within the property ranging from 7.5 to 10.5kW! No reports of problems from the owners in the 5 years they'd owned the place!
 
Thanks for reply, I wasn't suggesting you'd said regulations were wrong. My point was that whether doing electrics or car repairs, if you do the work to the regulations, or the the workshop manual, and some one says you've not done it right, or that it is dangerous, then they must be saying the regs or workshop manual is wrong. Because that person has no formal qualifications in that subject doesn't necessarily mean it's wrong. And thanks for the point on the split board. I was going to do that. Glad I'm on the right track!
 
Thanks for reply, I wasn't suggesting you'd said regulations were wrong. My point was that whether doing electrics or car repairs, if you do the work to the regulations, or the the workshop manual, and some one says you've not done it right, or that it is dangerous, then they must be saying the regs or workshop manual is wrong. Because that person has no formal qualifications in that subject doesn't necessarily mean it's wrong. And thanks for the point on the split board. I was going to do that. Glad I'm on the right track!
I will take issue on this Percyprod, a Motoring workshop manual is a how to guide, BS7671 the wiring regulations are not, so there is a difference in my opinion.
 
Thanks for reply, I wasn't suggesting you'd said regulations were wrong. My point was that whether doing electrics or car repairs, if you do the work to the regulations, or the the workshop manual, and some one says you've not done it right, or that it is dangerous, then they must be saying the regs or workshop manual is wrong. Because that person has no formal qualifications in that subject doesn't necessarily mean it's wrong. And thanks for the point on the split board. I was going to do that. Glad I'm on the right track!
No one is suggesting that you are not capable of doing the installation work. Many experienced competent people are quite capable of doing a good installation job. What is important is that you are able to do the necessary inspection & testing, be fully competent at doing the required tests and procedures and have the knowledge to understand and interpret the results.
You may argue that all the install is brand new and if done correctly will be trouble free. Well in the majority of cases this might be so. BUT the whole point of testing is to make sure there are no faults and that the installation is safe to use. Occasionally even brand new installs have unforeseen problems regardless how much care and attention is taken.
One of my apprentices had just that last week. A brand new install throwing up a high R1 & R2 reading. Turned out to be a "brand new" faulty isolator terminal. If no test had taken place and this circuit was energised it would have been potentially dangerous.
 
[/QUOTE]I'll add that when I was serving my time we completed an EICR on a 12 bed guesthouse (with attached 3 bed owners accomodation). The guesthouse was supplied with a standard "100A" domestic supply. The install was spread over 3 or 4 boards to accommodate various extensions/renovations over the years. There was in total 13 electric showers within the property ranging from 7.5 to 10.5kW! No reports of problems from the owners in the 5 years they'd owned the place![/QUOTE]


Hi resu,
I know this is an old thread, but I'm wandering what code you gave the property with 13 electric showers.
The reason I ask is I have been to quote for 7 bed guest house and they have 8 electric showers on one split board CU. supplied by 1 phase. Obviously I would codee C2 for overloading of each of the 63A rcd,s and the 100a rated main switch.

The dilemma I had was the customer asked if the showers are split between 3 boards would it comply. I feel no so would still give a C2 as the main incoming 100A fuse would be overloaded.

There is no visible sign of overheating inside the CU.

I have to make clear I am just at the quote stage and pointed this out to the owner as I was having a quick look to give him an estimate.

I have in the past split 5 existing showers in a guest house and gave it a C3 with a big statement/ risk assessment and advisory attached to eir.
But 8......
 
Last edited:
C2 for the overload

1 CU , 2 CU's or 3 CU's - that is irrelevant/
 
I'm going to rewire my house, and was wondering if it's ok to have 2 shower circuits as well as cooker, sockets and lights off 1 cu, or would it be better to have 1 of the showers on a separate cu, because of the available water pressure the 2 showers are never on together.
You can put 145 shower circuits in if you like, just make sure your supplied load can cope with them, that aside, don't forget to allow the extra building work you need to be done now, might as well widen all those doorways in your house at the same time so your only making a mess once, at your age it won't be long before your wheel chair will get used more and more :D
 
Agreed, thanks murdock.

Yes, we coded it C2, along with a few other things!

They've recently sold up and the new owners have just had planning permission granted for a 14 bed extension. Hopefully they're planning a major overhaul of the existing part of the property too!
 
Must agree with Andy, this has been going on far too long, getting ridiculous, it was January when I first posted it. You obviously haven't got enough to do.
 

Reply to Diversity factor on rewire in the DIY Electrical Advice area at ElectriciansForums.net

Similar Threads

In a property with two consumer units one for the ring main etc., and the other for the 1970s storage heaters (storage heater CU looks like it’s...
Replies
14
Views
1K
90s house electric issues continues 🥲 So after getting some good advice here I've managed to sort out some of the heating issues so thank you...
Replies
2
Views
277
In my bathroom there is supplementary bonding of the bath, bath pipework, and basin pipework before it goes into trunking and exits unconnected in...
Replies
6
Views
425
Hi I've been planning to fit an outdoor junction box at the front of my house to hide a large brickwork hole and properly house the wiring...
Replies
9
Views
954
I have been asked to change cu from old fuse board which has 6 fuses. Only 4 fuses are used. The first fuse feeds cooker circuit. This is not used...
Replies
17
Views
875

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock