Radial wire size?

[Yorkshirebloke]

Evening all,
Hopefully a couple of quick questions for you....
I'm thinking of putting a new radial circuit to the conservatory. SWMBO would like an electric wall type heater in there, and there is 3 double sockets, at the moment to run 2 uplighters and a tv.
Will 4mm be sufficient do we think? Cable will be run clipped to the bottom of the floor joists (8m from CU to conservatory) and then run in the cavity another 4m to the furthest socket.

Secondly, upstairs I'm thinking I'll run 2 radials (each side of the house) can I run them on one RCBO or do i need to separate them?
Many thanks all
Alex

 

[winston1]

4mm will be more than sufficient. Will this be a new circuit? If so it is notifiable.

Two radials can run off 1 RCBO. Once again notifiable if a new circuit.

 

[Yorkshirebloke]

Ah good stuff thanks.
Yes I appreciate it's notifiable. Im doing the grunt work for the sparky that's all.

 

[ban-all-sheds]

Then the sparky is the only one who can answer your questions.

He is the one who will have to sign this:

I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2008, amended to 2015 except for the departures, if any, detailed as follows:

and he will be the one to declare that he complied with the Building Regulations.

Do not present him with decisions made by other people and expect him to accept responsibility for them.

 

[Yorkshirebloke]

Then the sparky is the only one who can answer your questions.

He is the one who will have to sign this:

I being the person responsible for the design, construction, inspection & testing of the electrical installation (as indicated by my signature below), particulars of which are described above, having exercised reasonable skill and care when carrying out the design, construction, inspection & testing hereby CERTIFY that the said work for which I have been responsible is to the best of my knowledge and belief in accordance with BS 7671:2008, amended to 2015 except for the departures, if any, detailed as follows:

and he will be the one to declare that he complied with the Building Regulations.

Do not present him with decisions made by other people and expect him to accept responsibility for them.

He's on holiday in Ibiza, I'm pretty sure a text asking him the question would be as welcome as a sh1t sandwich........

 

[ban-all-sheds]

He's on holiday in Ibiza

Then wait until he gets back.

I'm pretty sure a text asking him the question would be as welcome as a sh1t sandwich........

Likewise just assuming that he will sign documents to say that he made all these decisions.

 

[Yorkshirebloke]

Then wait until he gets back.

No. I won't. I asked a question on here to satisfy my own mind.

Likewise just assuming that he will sign documents to say that he made all these decisions.

Im assuming he will be absolutely fine knowing I asked a question to safeguard MY house.

 

[phatboy]

Two radials can run off 1 RCBO. Once again notifiable if a new circuit.

Why only 2?

 

[Yorkshirebloke]

Why only 2?

For upstairs. The way the sockets are located it's not an easy ring, so I am looking to run 2 radials up each side of the landing as it were.
Downstairs it will be a ring for the kitchen, the radial for the conservatory and a radial for the remaining sockets downstairs.

 

[JohnW2]

Why only 2?

One could, in most respects, run as many radials (and/or ring finals) off one MCB or RCBO as one wanted to, limited only by the terminal capacity of the device. However, the limitation of total current across all the circuits, and the fact that a fault on one of the circuits would take out all of them, would usually make it less than a clever idea.

Kind Regards, John

 

[ban-all-sheds]

Im assuming he will be absolutely fine knowing I asked a question to safeguard MY house.

No - you are assuming that he will be absolutely fine with returning from holiday and finding that you expect him to sign a declaration that he did something which he did not.

This has absolutely nothing to do with you "safeguarding" your house.

This is clearly, if not a complete rewire then some significant alterations. Why, I wonder, are you so vehemently opposed to being courteous enough to allow him to exercise his professional responsibilities properly?

 

[ban-all-sheds]

... run in the cavity ...

How are you planning to comply with 522.8.4 & 522.8.5?

Remember, you'll be expecting a professional electrician to sign a document to say that he installed the cables in the cavity, and that he did it in a way which complied with the regulations.

 

[Yorkshirebloke]

I could get involved in a discussion with you about the all of the above...........

But quite frankly I can't be bothered, and I'd sooner listen to a skilled tradesman.

Thanks anyway. You have yourself a lovely day

 

[ban-all-sheds]

I could get involved in a discussion with you about the all of the above...........

I very much doubt that.

But quite frankly I can't be bothered, and I'd sooner listen to a skilled tradesman.

I wonder why you are so utterly determined to ignore the possibility of problems that might arise simply from your refusal to just wait a short while so that you can ask your skilled tradesman questions which are his to answer by right, and so determined to press on with a plan which is at best discourteous and at worst doomed to fail?

Actually - I do have a theory.

I wonder how many others here are beginning to share it?

 

[Yorkshirebloke]

I very much doubt that.


I wonder why you are so utterly determined to ignore the possibility of problems that might arise simply from your refusal to just wait a short while so that you can ask your skilled tradesman questions which are his to answer by right, and so determined to press on with a plan which is at best discourteous and at worst doomed to fail?

Actually - I do have a theory.

I wonder how many others here are beginning to share it?

Lol, sweet cheeks your theories matter not to me, and most of the forum for that matter.

The bit you are clearly champing at is the cable run through the cavity in the dwarf wall.
Sigh.
The cable is already there. It's been there since 1999 when it was installed. It hasn't caused damp. In fact every forum I frequent has pretty much said it is a horse sh1t reg and it won't cause problems.
HOWEVER......
It is a reg and one I will be addressing. I will be addressing it because the conservatory will be coming down in the next 3 years and a new one of a different shape replacing it.
So, to make my life easier for when it does come down I wanted to supply it with it's own radial circuit which will be sufficient to use when the new conservatory goes up. The conservatory as of the minute is on the end of a radial circuit through the kitchen sockets. The house at the moment has very little floor boards and is in a state where it's really easy to run this extra wire, so makes sense.
So, as you can see, I'm not causing the sparky any grief and I'm future proofing the house.
I grant you that it will NOT be 100% compliant as of the day the sparky signs it off. It has however been like this since 1999 and what I'm doing will make it safer as of the moment, and specifically in the long run. I know this. I have taken an educated risk. I am MORE than happy with my decision. If the sparky doesn't like it, I can quite easily take the wire out the CU and leave the conservatory without power.

But, as always, thanks for the input.