Self Build Advice Please - consumer units, sockets & switches...

[janner43]

Hi all,

We are doing a self build 2 bed bungalow in Devon which is going to be very highly insulated with u-values of..
Floor 0.15
Walls 0.14
Ceiling 0.11

With an air tightness factor of 0.8
MVHR with 89% efficiency

* Our other design spec includes no central heating system (not required with the previous specs), we'll just add a panel heater to act as a top up for the stored heat within the home when required. The MVHR should do the rest.

* An "experiment" with no central hot water - just local instantaneous water heaters (3 @ 12kw) where required. Half the plumbing, no dead leg of water, no waste hot water stored. We are not having a bath, so an instantaneous electric shower (9.5kw)

* We are having a 3.7kw solar array. The whole concept is based on the PassivHaus model with a couple of tweaks.

I don't really want to debate the design concepts - feel free to comment if you like, though .
The whole idea has been predicated on thinking differently about the designs when it comes to the heating and water heating together with an avoidance of the connection costs, plumbing, boiler purchase, boiler servicing costs associated with a gas connection (which is available).

We have a great, fully qualified sparky on the project who grew up with our son & is a good guy. I know he'll give us good advice, but I would appreciate several points of view on this please. He is kindly not supplying materials & is letting me source those to save some money. He is also arranging for a pal with the MCS ticket to commission the solar array at mates rates.

That's the background, now to the questions...

1) Consumer Unit...
I wondered if it would be a good idea to have two consumer units...
One for the heavy items - three 12kw water heaters and one 9.5kw shower
One for everything else

Or just get one large unit?

Would there be an issue with the solar array connectivity if we had two consumer units?

I like the idea of splitting as many of the circuits as possible, so what sort of config would you design if this was your build?

2) What brands are the best value for money - I'm familiar (Dad was an electrician for decades, started his trade in the 1950s) with MK, Wylex - but are they as good now as they were or are other names just as good?

3) Any recommendation on which make of sockets & switches to get?

4) Any recommendations as to the cheapest place to buy the gear from please? I already have a Trade Account at Travis Perkins (and Trade Point - don't laugh, it might be handy... )

I hope I have given you enough information & thanks in advance for taking the time to read this and for any answers / opinions / recommends you might be willing to give.

Cheers all.

 

[sean_ork]

Take your point it’s not an investment.

That’s good, because with respect you may be creating something, were no one would want to lend on, or buy it, without wanting to knock you for cash to conventionalise it. What’s the point of investing in a significant asset that can’t easily be liquidised ?

Just random thoughts, please feel free to ignore.

They are very random thoughts, especially as the opposite of what you've posted is true ...

House built to this general standard are the norm for many of our more northerly neighbours, perhaps not all to PH standards but all highly insulated and a measured target air tightness - sooner or later such house will be standard here, there's no doubt about that.

Even up here in the UK there's many conventionally built houses that have to be purchased outright, as no mortgage company will lend on it - ask yourself why.

Also, the wise planners here have efffectly banned brick buildings, you simply won't get a warrant for putting up such a structure - ask yourself why.

 

[sean_ork]

I've never put any sort of relays in, but the most we fitted was 3 showers on one 100A supply in a house which had no problem.
Don't forget the chances of people all showering at the same time in a single house are pretty slim, especially since the water pressure would drop away to a dribble!

Theres no need for relays, just fit a shower priority device which negates any chance of an issue, or a dribble


Shower Prioity Units | MeteorElectrical.com

 

[Leesparkykent]

Theres no need for relays, just fit a shower priority device which negates any chance of an issue, or a dribble


Shower Prioity Units | MeteorElectrical.com

That is a board with relays/contactors.

 

[sean_ork]

That is a board with relays/contactors.

Yep, ready built, tested, approved, proven - not built using bits found in the back of your van

 

[Leesparkykent]

Yep, ready built, tested, approved, proven - not built using bits found in the back of your van

And not amm3 compliant so would have to have an enclosure built round it. TBH I have enough confidence in my ability to build my own if I never needed to......i was just pointing out that they are contactors/relays as you said no need for relays.

 

[plugsandsparks]

I'll double check with Western Power, but having spoken with them about the maximum size single phase domestic connection & them saying it is 100amp I can have, I will be pretty annoyed if it is the old 65amp service. Thanks for the reminder.

63A is not old. 100A is the maximum for a std supply but it is NOT a given. That's why I suggested you get it in writing. I was very recently proposed a 63A supply by WPG for a new build.

 

[newtothis]

They are very random thoughts, especially as the opposite of what you've posted is true ...

ha ha Sean, it might be more accurate and friendly to say ‘your truth’ is different to ‘my random thoughts’.

My thoughts are only based on what I read at this website, Why Passivhaus to summarise my understanding, or lack of:
it’s a precise standard worked out by boffins. Comes with certification and approved contractors/ and architects You tweak it to save money at the building stage and it’s not the ‘real deal’ ie not certifiable, therefore the USP vanishes, leaving an devalued asset that‘s harder to liquidise. In the real world with all it’s uncertainties, changes, shocks, and surprises that's not a good thing to do with a significant asset.

My second point is based on me buying and selling houses.
Dual fuel or three or four types of energy taking advantage of the efficiencies and benefits costs of each type is the preferred option.

Yet another gap in my understanding, I cannot even visualise what some of the items will look like, I’m probably well off the mark when I think of instantaneous water heaters, do they look like something you’d find in a Portacabin on a building site ?

Maybe what I’m saying, is if your going down the Passivhaus route, do it right, using the tradesmen and professionals they recommend (or in reality have paid for the Passivhaus ticket). Whether or not, as others suspect the OP may be attempting the electrical installation, with an largely unpaid mate in background to attempt to 'legalise' his DIY on the electrics is none of my business. :lol:

It's a very interesting topic. To the OP thanks for starting it, and I wish you every success with your project.

 

[sean_ork]

And not amm3 compliant so would have to have an enclosure built round it. TBH I have enough confidence in my ability to build my own if I never needed to......i was just pointing out that they are contactors/relays as you said no need for relays.

Could you build the same for that price ?

 

[sean_ork]

ha ha Sean, it might be more accurate and friendly to say ‘your truth’ is different to ‘my random thoughts’.

My thoughts are only based on what I read at this website, Why Passivhaus to summarise my understanding, or lack of:
it’s a precise standard worked out by boffins. Comes with certification and approved contractors/ and architects You tweak it to save money at the building stage and it’s not the ‘real deal’ ie not certifiable, therefore the USP vanishes, leaving an devalued asset that‘s harder to liquidise. In the real world with all it’s uncertainties, changes, shocks, and surprises that's not a good thing to do with a significant asset.

That wasn't supposed to sound unfriendly, sorry.

The formalisation of the PH "standard" only came about as so many forward thinking buildings/architects/self builders/home owners were working independently towards the same thing - the "standard" was formalised as a moveable goal to be achieved during design/build - there's many many different ways to achieve formal accreditation, if the tweaks result in a failure to achieve formal PH accreditation, the house will still more far more habitable and energy efficient than one constructed to the baseline of current building regulations.


Instantaneous heaters are often fitted to site huts, but (I posted a link to one previously) they aren't all grubby plastic boxes stuck to the wall with bluetac.

Ask the average builder to quote for building a PH and he'll likely first wonder where the beer cellar will be, ask the average builder what a cold bridge is and he'll point you at the crossing over the Forth. I agree the builders need to know what they are doing, but there's no accreditation to pay for, PH isnt a club you have to pay to join - you simply have to prove you can build to a standard, a standard that's far far higher than our current regs.

Making provision for multi fuel is wise, and its been mentioned in this thread previously.

 

[janner43]

ha ha Sean, it might be more accurate and friendly to say ‘your truth’ is different to ‘my random thoughts’.

My thoughts are only based on what I read at this website, Why Passivhaus to summarise my understanding, or lack of:
it’s a precise standard worked out by boffins. Comes with certification and approved contractors/ and architects You tweak it to save money at the building stage and it’s not the ‘real deal’ ie not certifiable, therefore the USP vanishes, leaving an devalued asset that‘s harder to liquidise. In the real world with all it’s uncertainties, changes, shocks, and surprises that's not a good thing to do with a significant asset.

My second point is based on me buying and selling houses.
Dual fuel or three or four types of energy taking advantage of the efficiencies and benefits costs of each type is the preferred option.

Yet another gap in my understanding, I cannot even visualise what some of the items will look like, I’m probably well off the mark when I think of instantaneous water heaters, do they look like something you’d find in a Portacabin on a building site ?

Maybe what I’m saying, is if your going down the Passivhaus route, do it right, using the tradesmen and professionals they recommend (or in reality have paid for the Passivhaus ticket). Whether or not, as others suspect the OP may be attempting the electrical installation, with an largely unpaid mate in background to attempt to 'legalise' his DIY on the electrics is none of my business. :lol:

It's a very interesting topic. To the OP thanks for starting it, and I wish you every success with your project.

We are building "towards" PassivHaus. As you say, PH has very specific standards, but in and of itself it doesn't mean anything to get the "certified PH" badge. It just adds £thousands for no benefit. Some of our standards are better than PH.

EG it all depends on where you are, geographically. The PH standards are the same, but heating costs in Devon are already significantly lower than those in Orkney. Even in an old draughty house. And for the last time - I am NOT DIYING THE ELECTRICAL INSTALL!!!!!!!!!!!!!!!!!!!

This thread has done exactly what I hoped - gained a lot of wisdom and insight from a good number of professionals. Many of whom disagree on certain points, but that is exactly why I wanted to ask the question in this sort of forum.

 

[Leesparkykent]

Could you build the same for that price ?

Probably if not cheaper.

 

[DPG]

It's certainly been an interesting debate. I'm sure as time goes on some of these 'new fangled' ideas will become the norm as we strive for efficiency. Remember, brick houses were a wild new idea after the mud huts! I sometimes think some people would be happy if things never changed and we still lived in mud huts Daz

 

[sean_ork]

Probably if not cheaper.

Yes of course ....

 

[Midwest]

Don't forget the chances of people all showering at the same time in a single house are pretty slim, especially since the water pressure would drop away to a dribble!

You've obviously forgotten what it's like to be a teenager. Turn on shower, wait ten minutes for it to warm up nicely, then have shower for 15 minutes, cos I'm not paying the bill.

 

[newtothis]

That wasn't supposed to sound unfriendly, sorry.

No probs at all Sean, I just put the ‘friendly’ bit in for a laugh - hence the cheeky tongue emoticon.
Watching ManU V southamton - I have beers here, that need to be drunk.:17:
Have a nice weekend all.