Separate radial for oven/boiler/etc?

[wh666]

Hi all, just looking for some advice and hopefully a consensus. Im not 17th edition but quite competent. Doing my own rewire to a high standard and then getting a fully qualified aquaintence to sign it all off. At the moment though, everyone is off on holiday and before I start I have a burning question .......

I will be doing a separate ring for the kitchen as we all know its advisable, however the rest of my downstairs is only a few sockets, is it ok to put the rest of the downstairs sockets and upstairs on one ring, then keep the kitchen on one of its own? Seems silly to have three rings when I've only got a small three bed mid terrace!




Then the main question is in the kitchen, I will have an extractor hood, single electric oven all singing and dancing modern one (no hob as its gas) and a boiler. I dont have the original box with the ratings for the oven by the way. I imagine it would be a bit of a load to shove it all on fused boxes on the same ring?

Instead I was thinking of having the extractor which is hardly any load on the ring on a fused box, then the combi condensing boiler and the single oven on a 45a+ radial. Please correct me if this needs some re-thinking?

I know you would usually just have an oven on a 45a radial but thats double ovens with hobs. Im no plumber, so does anyone know roughly the load a boiler has on a circuit? It seems silly to have a kitchen ring, radial for the oven and a separate one for the boiler? Or what about if you think the oven still needs a separate radial, having the combi boiler on the ring with the extractor and the oven on its own radial?


I've tried searching the web, but there are so many conflicting opinions that its enough to confuse anyone ...


Hopefully someone more qaulified/experienced can help? Thanks in advance.

 

[Taylortwocities]

Doing my own rewire to a high standard and then getting a fully qualified aquaintence to sign it all off..

Well, your questions demonstrate that it cannot be to a high standard as you do not have the first idea.
And this aquaintance. Is he prepared to lie on a legal document that he designed, installed and tested the installation himself?
Electricians who are members of registration bodies are not alowed to do this.

You are going to do a rewire without having any idea of the actual loads??? Good grief

Edit: There may be opinions - ignore them - they are dust in the wind.

There are regulations related to wiring. It is called BS7671. Everything you need to comply with is in there.

 

[ricicle]

Doing my own rewire to a high standard and then getting a fully qualified aquaintence to sign it all off. At the moment though, everyone is off on holiday and before I start I have a burning question .......

Before we start let's cut to the chase - we have heard this one so many times before about mysterious Electricians being away on holiday. Is this really the case or are you blagging.
Either way it won't really affect the answer you are given.......

 

[wh666]

Before we start let's cut to the chase - we have heard this one so many times before about mysterious Electricians being away on holiday. Is this really the case or are you blagging.
Either way it won't really affect the answer you are given.......

Whow, no need for you to both be so rude about it. Yes the electrician is on holiday spending a bit of time with his kids while they're off as well.


If you're not prepared to help by venturing an opinon why comment?

 

[wh666]

Doing my own rewire to a high standard and then getting a fully qualified aquaintence to sign it all off..

Well, your questions demonstrate that it cannot be to a high standard as you do not have the first idea.
And this aquaintance. Is he prepared to lie on a legal document that he designed, installed and tested the installation himself?
Electricians who are members of registration bodies are not alowed to do this.

You are going to do a rewire without having any idea of the actual loads??? Good grief

Edit: There may be opinions - ignore them - they are dust in the wind.

There are regulations related to wiring. It is called BS7671. Everything you need to comply with is in there.

Well obviously I did have "the first idea" as I stated it. I never said I didnt have an idea of actual loads as Im well aware of them for the lighting circuit and most of the mains. Also im aware of regs including Part P.

However my experience lets me down when it comes to combi boilers, all I asked is a simple question ..

 

[1john]

more circuits = better
less circuits = worse

it seems silly to have alot of major things required for personal comfort on one circuit to me

 

[ban-all-sheds]

At the moment though, everyone is off on holiday and before I start I have a burning question .......

Then damp it down and wait for the acquaintance to get back from holiday. If you want him to sign a declaration to say he did the design then you ought to let him actually do it.

I will be doing a separate ring for the kitchen as we all know its advisable,

No we don't.

however the rest of my downstairs is only a few sockets, is it ok to put the rest of the downstairs sockets and upstairs on one ring,

You tell us.

You're perfectly competent and can work to a high standard - what's your take on 314.1 regarding that?

then keep the kitchen on one of its own? Seems silly to have three rings when I've only got a small three bed mid terrace!

Does it?

Why do you think that minimising the numbers of circuits equates to good design?

Then the main question is in the kitchen, I will have an extractor hood, single electric oven all singing and dancing modern one (no hob as its gas) and a boiler. I dont have the original box with the ratings for the oven by the way. I imagine it would be a bit of a load to shove it all on fused boxes on the same ring?

Or instead of imagining things you could look at the oven instructions, or look up the specifications on the manufacturers site, or look at the rating plate on it.

Instead I was thinking of having the extractor which is hardly any load on the ring on a fused box, then the combi condensing boiler and the single oven on a 45a+ radial. Please correct me if this needs some re-thinking?

So it's silly to have 3 rings, but not silly to have a 45A circuit for an oven?

I know you would usually just have an oven on a 45a radial but thats double ovens with hobs.

Which you haven't got.

Im no plumber, so does anyone know roughly the load a boiler has on a circuit?

Ask the plumbers.

It seems silly to have a kitchen ring, radial for the oven and a separate one for the boiler?

Does it?

Or what about if you think the oven still needs a separate radial, having the combi boiler on the ring with the extractor and the oven on its own radial?

What about you ridding yourself of the ideas that you should strive to reduce the numbers of circuits, and that rings are the only answer for socket circuits?

 

[ajrobb]

I was thinking of having the extractor which is hardly any load on the ring on a fused box, then the combi condensing boiler and the single oven on a 45a+ radial. Please correct me if this needs some re-thinking?

Oven on 13A socket, boiler on 3A fused spur and extractor drawing less than 1A - whole lot on radial in 2.5mm² protected by 20A RCBO. If you go 45A, you'll have problems squeezing 10mm² cable into junctions designed for 2.5mm². Put concealed sockets (oven and extractor) on accessible 20A isolator switches.

You didn't mention the hob's gas igniter but that wouldn't take load to 20A. Another concealed socket on an accessible 20A isolator switch.

If you are not fully qualified, you should notify your local BC of the work under Part P and only they can sign it off.

You can put several 13A sockets on a 20A radial as long as load diversity keeps total current within limits. I've gone for a similar design; washing machine, boiler, extractor and gas igniter on a 20A radial with isolator switches for concealed sockets. That got through first fit inspection by BC.

 

[Taylortwocities]

I installed a single oven last week - it required 16A
I installed a combi microwave recently, it too required a separate 16A feed.

You/your friend need to determine exactly the loads adn then do a design. That is, after all, the first thing any competent electrician must do when designing and installing anything.

Then you get into cable size calculations......

 

[ajrobb]

I installed a single oven last week - it required 16A

Looking at data sheets for Hotpoint single oven, the fuse protection should be a maximum of 16A (to protect the 1.5mm² wiring) but the maximum power drawn is 2.4kW at 240V (i.e. 10A for resistive load). A 13A socket should be adequate. They even say the product should be "unplugged" before servicing.

 

[slup]

Your oven isn't necessarily the same as the one Taylortwocities installed though is it?

My Bosch single oven is rated at 3850W, and the combi microwave at 3400W - so neither of those could go on a 13A socket.

 

[ajrobb]

Your oven isn't necessarily the same as the one Taylortwocities installed though is it?

My Bosch single oven is rated at 3850W, and the combi microwave at 3400W - so neither of those could go on a 13A socket.

OK, so some ovens need a dedicated radial and a qualified electrician to install them. Others can happily run off a 13A socket. I suspect that most cheap ovens fall into the latter category.

As said, the actual loads must be known for a working design. IF they are prepared to restrict themselves to units that can run from 13A sockets, then a 20A radial or 30A ring would probably be OK.

Trying to use a 45A radial for anything other than a cooker point (or fuse box) is asking for trouble. I'm guessing they could run single 13A sockets on multiple 2.5mm² spurs from a switched cooker point. However, given the switch is labelled COOKER, I guess they should be restricted to cooking appliances (oven and gas igniter).

 

[OwainDIYer]

Others can happily run off a 13A socket. I suspect that most cheap ovens fall into the latter category.

I suspect that most cheap ovens are Continental and intended for 16A circuits, which don't fit too neatly into the normal British way of doing things.

 

[ajrobb]

Others can happily run off a 13A socket. I suspect that most cheap ovens fall into the latter category.

I suspect that most cheap ovens are Continental and intended for 16A circuits, which don't fit too neatly into the normal British way of doing things.

I checked Hotpoint's catalogue and none of their single ovens draws more than 13A. The first few Zanussi single ovens I checked need a 13A fuse. However, point taken, continental ovens may be designed for 16A at 230V so slup's Bosch draws just over 16A at 240V.

 

[RB2004]

Trying to use a 45A radial for anything other than a cooker point (or fuse box) is asking for trouble.

lol, apparently some people dont know that.
saw some wiring the other week... 10mm cable in the CU, using a 45amp MCB.

but in the kitchen, somebody had wired the kitchen sockets into the old cooker connection point... and run 2.5mm around the room in a radial to the sockets.. while maintaining the 45amp mcb.