Futureproofing. Wiring for photovoltaics

[TalentlessAmateur]

As I am planning getting a property rewired, I was thinking about making sure that I pre-empt possible future works. One such could be photovoltaic generation via panels in the roof. I don't really think I'll be considering this anytime soon as unless energy prices shoot up dramatically or the technology gets much cheaper I doubt it will be worthwhile.

However, things may change, and if it is cheap and easy, and makes PV installation easier at a later date, I would consider getting the ground ready.

Would it be worth getting a 'spare' circuit set up to the loft ready? What would this circuit be like?
Could it be used for anything else in the meantime?.... 13A socket for instance?

I'd be getting a light fitted up there anyway as I'm sick of going into lofts with a headtorch.

Many thanks in advance.

 

[ban-all-sheds]

Main thing would be to strengthen the roof...

And run some plumbing up there - PV is a pipe dream but heating water does actually work.

 

[Adam_151]

Not sure if there is some variation between makes, but the system I came across, the instructions request a 4mm radial, fed via a C16 mcb, this is fed through a rotary isolator adjacent the main DB (very important), and clearly labeled as PV isolation point, and there is normally a meter that goes after this iso as well... but if you had the cable into the DB and had length left on it...

 

[TalentlessAmateur]

I am inclined to agree with you. Solar hot water sounds very good but would be a pretty big project and am not even considering it as yet.

In 10 years time PV may be more cost effective (either by technology or price of power) so that is why I'm thinking about it. If one cable from the consumer unit to the loft would make the installation easier, and cheaper, then it may well be worth doing it as part of the rewire. If the technology is more complex to install, then I'd be tempted to let it slip. Problem is, I don't know!

Cheers.

 

[ban-all-sheds]

If the price of centrally generated electricity gets to the level where PV at these latitudes is commercially competitive the economy and society will go into meltdown.

 

[seasickstevie]

If possible, I'd be thinking about a duct and traps in the floor etc. at strategic points, rather than pulling a cable through.

Always a good idea to create a route from CU to loft if possible, if you're looking to be future proof.

 

[flameport]

Always a good idea to create a route from CU to loft if possible, if you're looking to be future proof.

And also if you want to contravene Part B of the building regulations.

 

[ban-all-sheds]

Sometime you should go to the foot of your stairs and look up at the ******* great vertical path from the ground floor to the loft hatch.

 

[1john]

you could always run a few lengths or 16mm2 twin and earth to the loft for future proofing, this should cover most bases.

tbh I would worry about it when you need to, if your supply is on an exterior wall with consumer unit near by then a conduit could always be installed up to the loft / roof area in the future. My money would be spent on solar water heating, this is easily acheivable NOW and you can start saving NOW, cant see us ever mustering enough energy from the sun to catisfy our own needs unless drastic changes in lifestyle are made.

 

[crunchynut]

The comparison between commercial market prices and private energy generation is IMO misleading Ban; it will take many yrs before PV could even get close to this, even in the very most favourable climates.

The ability of the UK to generate meaningful (ie commercial) PV energy is widely acknowledged as pointless. If someone was to get a PV array on their roof they would currently suffer a terrible (financial) payback time. They would however get to feel marginally smug!

I agree re solar heating.

PV is not without it misgivings.

 

[Stoday]

I guess the "experts" here haven't heard of the feed-in tariffs that pay you for generating "green" electricity, hence they think PV is uneconomic. It's not. It's very much economic if the PV is installed by a government approved contractor. You can then enjoy a completely uneconomic "feed in" tariff" whereby you get an enormous subsidy and the uneconomic part is paid for by others

First you get paid 41.3 p/kWh for all the electricity you generate, including that which you use yourself. Moreover, this incentive (bribe?) is index linked with RPI and is paid tax free. On top of that you get an extra 3p/kWh for all the electricity you export to the grid. These payments are guaranteed for 25 years.

I'm sure all of you will be overjoyed to learn that the source of this subsidy is other consumers, including you. That subsidy is, in effect, only available to someone who has £20k to spare to pay for the system, so must be well-off. The cost of that subsidy is paid by other consumers, including the poorest. It's the previous Labour government that's to blame. They got their just desserts (a boot in the arse) but this sort of thing hasn't died with them (yet).

 

[Chri5]

Always a good idea to create a route from CU to loft if possible, if you're looking to be future proof.

And also if you want to contravene Part B of the building regulations.

Thick hat on, explain please

 

[maltaron]

The payback system looks brilliant until you work out the true cost. It still takes the full 25years plus for payback, and one major problem is "government approved contractors" which puts at least 20% on the initial cost. I have looked into this as I am just about to start a South facing extension and have come to the conclusion that PV power is possibly worth considering for a young person with cash to spare. And it should be remembered that the "guaranteed for 25 years" payments spans 5 parliaments in a virtually bankrupt state.

 

[Chri5]

Try reading this thread:-


//www.diynot.com/forums/viewtopic.php?p=1597613#1597613

 

[flameport]

Regarding Part B, a continuous path from the consumer unit (probably on the ground floor) straight up into the loft space is likely to contravene B3 (4), which states:
(4) The building shall be designed and constructed so that the unseen spread of fire and smoke within concealed spaces in its structure and fabric is inhibited.

As for PV - a total crock. Only theoretically viable because of the FIT tarrifs, but:
1. The FIT tarrifs will NOT be lasting for 25 years or anything like that. Law or not, they will disappear as soon as the system becomes to expensive to operate.
2. PV systems will require significant maintenance over their lifetime, which the proponents of PV systems conveniently forget to tell you about.
3. PV systems generate power at the very time most of it is not needed.
4. There are far better ways to spend £15k+ on energy saving or 'green' technology.