Re: Granny Flat

[danburns]

DNO - the people who own the supply network to your house.

Having asked these questions, and mentioning henley blocks, are you going to be installing this?

If so, can you let us know where you live - I've got some marshmallows that need toasting.

 

[Chri5]

Just for clarity......

What is being implied is that you should not take the supply from the existing main house head.

The main house is likely to be either a 65A or 100A supply and as yet you haven't supplied any information that would suggest that:-

Main hse + granny annex will be less than 100A

So what is being suggested is that you contact the DNO and get costs for a additional main supply with separate meter, rental and billing for the annex.

If you feel that this will be too costly with regard to initial installation (£1000 +++ or so is very possible) and then the added quarterly cost of rental and use then you need to be very, very careful and correct with you sums for total demand over the two sites.

Please photo the CU and existing main head and lets see if a solution away from the DNO is possible.

I would add that if you continue to think the annex should be electric heating and hot then it's very likely that the DNO will have to provide service and give you a new 65A or 100A head.

Finally if you intend to provide a water main, waste, BT and electric whats the issue with a gas main going in at the same time ?

 

[electronicsuk]

surely this is just a case of fitting some henley blocks?

You really seem to be struggling to accept that you aren't capable of this work.

To make absolutely clear, it is NOT simply a case of fitting henley blocks and splitting the supply off down whatever cable you feel like. Even if you do notify this to BCO (which I doubt you intend to do), it seems unlikely they will pass your work, as you haven't listened to a single bit of advice provided so far.

Thanks for your responses everyone.
In regards to a heat pump, i'll forget that , unless i win the lottery this week!

Why? An air source heat pump (a-la air conditioner) can be had for £250 or so off eBay these days. I installed a couple in my old house, one ran 24/7 for a year or so before I moved out and never had a single problem.

As to a lower kilowatt water heater i'll look into that (the 9kw i had in mind is provides instant hot water).

Unless you get a new supply from the DNO, you can pretty much forget instantaneous water heaters. All but the smallest (the type you occasionally see above sinks that provide just enough water to wash your hands) will be unsuitable for your existing supply. Take the advice that has been provided and consider an unvented tank with immersion heater. Oh, and although I'm not a plumber, I believe I'm right in saying that fitting an unvented system is NOT a DIY job. If your granny isn't killed by fire or electric shock first then she certainly doesn't need an exploding hot water tank.

The general concensus seems to be to run the cable from my existing meter and not my house CU which seems a good idea so does anyone know what cable size i would require for this (distance 35 metres, potential load 13kw) ?

That's funny, I thought the general consensus was that you should completely rethink the electrical loads you're considering and then get a good electrician in to design and install for you. Despite pretty much everyone telling you otherwise, you're STILL asking what cable to use for a 13kW load! Nobody is going to answer your question, as you're clearly a danger to yourself and others.

 

[Hainsey]

Well said electronicsuk but this guy makes me laugh so much it would be a shame if he stopped asking.

 

[Steve]

bluebird's gonna sell his local wholesalers out of 25mm² cable.