hooking up altenative power to the house

[riccol1966]

ok I am planning to have a renewable system with solar panels and battery and inverter, and a generator as backup to that also. All the kit to be installed in the garage and run a cable into the house. The plan is for this cable to feed into a changeover switch which then supplies a new consumer unit. Then I swap some of the existing circuits from the main CU to the renewable CU. With me so far?

Question is: what is the established, de facto way to earth such a system. Having read through posts on this I am not totally clear. A 230V inverter/generator puts out 115volts on both live and neutral. So
Q1) is it ok to bring a 2core L+N SWA cable to the house, and then run the earth from the cable gland to the new CU and on to an earth rod. I know this isolates the new CU totally from the grid, but does it give RCD protection?
Q2) I don't understand some comments on other posts such as: "if the generator has neutral and earth isolated then join them at the generator plug" Surely that sends 115v continuous to earth, which cannot be right?

Only a beginner on this, so can I have plan english answers please?

Thanks

 

[Steve]

A 230V generator puts out a sine wave. You have to tie the neutral to ground, in order that the phase carries an RMS of 230V to ground/neutral. Many properties are supplied this way, with combined neutral and earth to the point of entry.

I have to say, this is a very specialised area of electrics, and you would do best to get a fully qualified electrician in. You'd have to know the intricacies of earthing systems, and those of generator sets. Also, having 2 generators as you say, as well as the mains, will bring its own problems.

For example, how will you utilise the solar power if you have to actuate a changeover switch, isolating the mains supply? The DNO will have problems with it, regarding the possibility that their network could remain live, during scheduled maintenance outages, due to your equipment. You would probably have to submit drawings to them for approval.

In short, Dont do it.

 

[breezer]

waste of time too

 

[riccol1966]

thanks for your comments crafty, Actually I will be getting a fully qualified electrician in. And the new CU will be totally isolated from the grid. But I suspect not many electricians are aware of the neutral-earth issues on inverters/generators (could be wrong). So I need to ask the right questions when the new CU and CO switch are being installed. It would seem the best thing too do would be to join the neutral to earth at the CO, is that the usual method of dealing with this?

 

[breezer]

you have been told what you are doing is:

a) waste of time

b) expensive

c) not worth it in terms of you will spnd more than you save

so in all seriousness, why are you planning on going ahead?
I really would like you to help me understand what it is that makes you think you will save money / be "green"

 

[stevesey]

Don't suppliers of domestic wind turbines, solar panels have an out of the box solution for this. After what's the point in B&Q selling their £1500 wind turbine if they don't provide way to connect it up.

Perhaps they don't yet - but if they even want to make this sort of green energy mass market they will need to.

 

[breezer]

i wrote a post about these.

in short b q only sell them, price includes survey / installation, but my point / note was they are only g'teed for 5 years, but it will be at least 10 years before you get your money / investment back.

in short

waste of time
_________________________________

question to riccol1966 (the op)

i assume when you say solar panels you do mean electric solar panels?

if so please let me know where you are getting them from at a cheap price as i want some for something, but not what you are doing.

good reliable solar panels cost thousands

cheap 1 watt out put solar panels cost arond a tenner from maplin


quick idea

based on this price

500 watts of soalr power is foing to cost you £5,000

is your idea still good?

i want to try an experiment to charge a battery to run a light, yes i can buy a ready made kit, but i want to make one.

oh and do rememeber i did say cheap panes cost 10 /watt

you will want yours to last

 

[bernardgreen]

My two pence on the matter

Add an extra cold water in the loft to feed only the hot water tank.

Use all you alternative energy to warm this water so the feed to the hot water tank is warm. That way you reduce the amount of energy required from mains gas / electric to provide hot water.

 

[breezer]

do you mean use the old black painted rads in a box trick?

 

[bernardgreen]

do you mean use the old black painted rads in a box trick?

Along with car radiator and fan to recover heat from air in loft using some very simple control equipment using op-amps as comparators to decide whether to run the fan or not.

24 volt immersion heaters from wind generator

Condensing coil in extractor fan ducts from kitchen and bath room

 

[breezer]

oh yeah, the condensing coil in vents from bathroom and kitchen to extarct more heat using more energy to do it than you will extract, i forgot that one

perhpas the op should move to iceland.

 

[stevesey]

My two pence on the matter

Add an extra cold water in the loft to feed only the hot water tank.

Use all you alternative energy to warm this water so the feed to the hot water tank is warm. That way you reduce the amount of energy required from mains gas / electric to provide hot water.

Often though about doing this - but concerned that this lukewarm tank then presents a lovely breeding ground for bacteria. OK they will later get heated to 60oC but I seem to remember from O level biology that's not enough to kill them (68oC needed?).

 

[bernardgreen]

I know of one person with a plastic tank with this scheme and he has had no apparent ill effects from it. The tank has a tight fitting, almost sealed lid.

Anothed option would be a tank static water with anti bacterial and a coil through it taking water the the hot tank.

oh yeah, the condensing coil in vents from bathroom and kitchen to extarct more heat using more energy to do it than you will extract, i forgot that one

The fan is there anyway. the cooling coil is passive and circulation by thermo syphon

 

[tim west]

There are replies that state it's all a waste of time as it's not cost effective but surely cost is not paramount here but everyone doing their bit to save energy where possible (ignoring globalwarming for the moment and energy wastage, whether true or not) Resources are being plundered and if everyone did their little bit then big savings could be had in use of resources surely?

 

[Steve]

There are replies that state it's all a waste of time as it's not cost effective but surely cost is not paramount here but everyone doing their bit to save energy where possible (ignoring globalwarming for the moment and energy wastage, whether true or not) Resources are being plundered and if everyone did their little bit then big savings could be had in use of resources surely?

Photovoltaic solar cells just aren't powerful enough (yet) for powering parts of houses. Water heating solar cells are a good idea though.