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.

 

[Octopus]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

 

[telectrix]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

and what happens when all the air has been used up, and he's breathing in CO2?

 

[sean_ork]

and what happens when all the air has been used up, and he's breathing in CO2?

Clearly you don't know what MHRV is, or how it works.

 

[sean_ork]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

It's mechanically recovered by the whole house ventilation system.

 

[DPG]

I think people need to look towards these new ideas rather than ridiculing them and sticking to how things have always been done. If we didn't progress like this then we'd still be living in houses with no cavities and no loft insulation. And we'd still have houses full of 60W and 10W lamps. Daz

 

[janner43]

Back to a sensible question - you made a statement about the property being "sealed" or similar - how do you get rid of unwanted moisture?

and what happens when all the air has been used up, and he's breathing in CO2?

https://en.wikipedia.org/wiki/Heat_recovery_ventilation

Heat Recovery Ventilation the best way to remove and replace stale, moist and unwanted air from your home

:waving:

 

[telectrix]

I think people need to look towards these new ideas rather than ridiculing them and sticking to how things have always been done. If we didn't progress like this then we'd still be living in houses with no cavities and no loft insulation. And we'd still have houses full of 60W and 10W lamps. Daz

best thing since the hindenburg. a bit of savings through heat loss. £3000 to replace corroded wall ties and repoint half the house.

 

[janner43]

best thing since the hindenburg. a bit of savings through heat loss. £3000 to replace corroded wall ties and repoint half the house.

You got that right. On south / western UK exposures, ie West Scotland, West Wales, Cornwall and parts of Devon no-one should install cavity insulation - especially if they have exposed brick.

In other parts of the U.K. it should be alright, but I could take you to two houses I personally know of where the houses are colder after the cavity insulation. One has failing internal plaster because of penetrating damp. The cavity insulation gets wet, the house gets cold.

Not good

 

[sean_ork]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

 

[Leesparkykent]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

More often your find they are now mostly timber framed. As they are manufactured off site.

 

[sean_ork]

More often your find they are now mostly timber framed. As they are manufactured off site.

Most of them are up here, the kit goes up in two days, but even then there's still the daft preference for a brick outer, sticking to what they know.

 

[davesparks]

Yet builders are still throwing up shoeboxes faced with brick, just enough FG to satisfy the building inspector, dense block inner, and glueing PB to it.

That's so 1960s

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend thousands on fancy gadgets to plug in to the ancient sockets etc.

 

[davesparks]

Most of them are up here, the kit goes up in two days, but even then there's still the daft preference for a brick outer, sticking to what they know.

But a brick skin has worked for us for hundreds of years, so we kind of like it.
It does beg the question of what alternatives are readily available?

 

[sean_ork]

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend thousands on fancy gadgets to plug in to the ancient sockets etc.

Yep, developers don't care what the ongoing costs are to keep it warm, as long as it takes longer than 10 years to fall apart they are alright jack.

 

[Octopus]

That's because the overriding decider in mass built houses is cost, the less it costs to build the more money the developer makes.

Houses built for an individual customer can be built far better if the customer is willing to pay for it, but again people don't like to spend money on sensible things.
It's the same situation we come across as electricians, people begrudge spending a few hundred on improving electrical safety but will happily spend tens of thousands on a fancy new kitchen

corrected that for you!