Changes to connect a 16A (hardwired) oven to 13A socket

[JohnW2]

According to the specs for the Samsung there are:
Upper oven 1200W
Lower oven 1220W
Upper grill 1600/1100W
Lower grill 1100W
So, it would depend on what can be used at the same time.

Hmmm. That lot adds up (at worst) to 5,120W, so one has to wonder what the "3.6kW" previously mentioned refers to! It sounds as if, in getting a 3.6kW figure, they have already applied diversity (although I then make it around 3.1kW).

Whatever, I doubt that many of us would be too happy with that lot on a 13A supply - unless, as you imply, there are 'interlocks' to prevent it all being on at once.

This is the reply to someone asking "What is the amperage?" .... ".... as it requires a 32amp and a fused spur.... "

Hmmm

Kind Regards, John

 

[ban-all-sheds]

Do you, or does anyone, feel that one could legitimately invoke the concept of diversity here?

Ah - but is diversity to be used in the calculations for maximum demand of an installation, or to "allow" In ≤ Iz ≤ Ib?

The more I think about it the more I'm inclined to go with the former, not the latter.

 

[ban-all-sheds]

Upper oven 1200W
Lower oven 1220W
Upper grill 1600/1100W
Lower grill 1100W

So, it would depend on what can be used at the same time.

Usually not grill and oven. Can anybody get any combination of those numbers to add up to 3650?

This is the reply to someone asking "What is the amperage?"
http://ao.com/product/BT621VDST-Sam...ectric-Single-Oven-Stainless-Steel-15471.aspx
Thank you for asking this question I know there are many other customers out there who will be very glad you have brought this up as working out what components you need for installation can be confusing.
For safety reasons the Samsung BT621VDST oven must be hardwired in by a qualified electrician as it requires a 32amp and a fused spur.
I do hope this oven ticks all your boxes, if not let me know and I will do some research to help you find the right model for you.

So, who knows?

Well, for a start clearly not the person who wrote that "answer".

 

[JohnW2]

Do you, or does anyone, feel that one could legitimately invoke the concept of diversity here?

Ah - but is diversity to be used in the calculations for maximum demand of an installation, or to "allow" In ≤ Iz ≤ Ib? The more I think about it the more I'm inclined to go with the former, not the latter.

An interesting question. The answer to the first part is presumably yes. I think the answer to the second is 'no', in the way you've phrased it', but I think many would say that it is used to produce an 'effective' ('after diversity') value for Ib which then has to satisfy In ≤ Iz ≤ Ib

If that is not the case, then most of the advice given in this forum, and other places, about the application of diversity would actually be incorrect.

Kind Regards, John

 

[ban-all-sheds]

I'll un-think it.

 

[JohnW2]

I'll un-think it.

Fair enough. Does that mean that you agree with my interpretation (which, as I said, seems to be the basis of most advice one sees being given about diversity)?

Kind Regards, John

 

[ban-all-sheds]

Answered here as it's gone all off-topic generic.

 

[sgabello]

It would make so easy to add/remove/change cables

Don't see how in your case it would help - you don't have a circuit where you need to change cables, you need a whole new one.

Well...
It takes 5 minutes to add a new cable like this:
http://www.leroymerlin.it/catalogo/...avo-rete-h05vv-f-3-x-2,5-mm-bianco-34544741-p

to an existing tube like this:
http://www.leroymerlin.it/catalogo/...idotti/tubo-corrugato-25-mm-x-10-m-32444195-p

by using something like this:
http://www.leroymerlin.it/catalogo/elettricita/fili-e-cavi/sonda-3-mm-x-15-m-32906720-p



But I get your explanation about tradition.



Just to give everyone an update, I invited over an electrician and unfortunately he confirmed that I would need a new separate line and probably also a new consumer unit with RCD. The only way to do it, would be to run a new cable under the floor... not an option at the moment.

So... I guess I will have to compromise on the choice of oven and go for a 3Kw max.

Cheers everyone for the help! I'm so impressed by the number of very competent people on this forum! Out of curiosity, is any of you an electrician by trade?

 

[ban-all-sheds]

It would make so easy to add/remove/change cables

Don't see how in your case it would help - you don't have a circuit where you need to change cables, you need a whole new one.

Well...
It takes 5 minutes to add a new cable like this ... to an existing tube like this ...

That's not the sort of cable to use in conduit, and I'm not sure it would always be as easy as you think to pull 3 new singles though several m of flexible conduit (as it isn't twin-walled) which is snaking through a building. But it often can be a big help.

There are downsides - holing, and even more so notching, of joists becomes harder to do safely if your "cable" is 25mm in diameter. Wall chases need to be a lot deeper, and you might find that you don't have the thickness available for horizontal ones.

Just to give everyone an update, I invited over an electrician and unfortunately he confirmed that I would need a new separate line and probably also a new consumer unit with RCD. The only way to do it, would be to run a new cable under the floor... not an option at the moment.

And as I said - in this case you don't already have a circuit installed where you could pull larger conductors through, so even if your house had been wired using flexible conduit throughout you would still have to dig up the floor.

So... I guess I will have to compromise on the choice of oven and go for a 3Kw max.

Not necessarily - if you had the kitchen circuit converted to a 20A or 25A radial, you could connect the oven you wanted to it.

Out of curiosity, is any of you an electrician by trade?

I'm not, nor are Bernard or JohnW2. Don't think Andy is. EFLI is, don't know about the others.

 

[sgabello]

So... I guess I will have to compromise on the choice of oven and go for a 3Kw max.

Not necessarily - if you had the kitchen circuit converted to a 20A or 25A radial, you could connect the oven you wanted to it.

Interesting... how do I know what kind of circuit I have at the moment?
The MCB that connects the kitchen is 32A, and it has two red cables departing from the top (unlike the others with only one cable).

Could that mean that I have a radial circuit already?

Out of curiosity, is any of you an electrician by trade?

I'm not, nor are Bernard or JohnW2. Don't think Andy is. EFLI is, don't know about the others.

What a pity... I feel like I can trust you guys more than any electrician. Is anyone of you from London and happy to recommend a good electrician in SW area? After reading this thread... anyone vetted by you, has to be very good.

 

[ban-all-sheds]

Interesting... how do I know what kind of circuit I have at the moment?
The MCB that connects the kitchen is 32A, and it has two red cables departing from the top (unlike the others with only one cable).

Could that mean that I have a radial circuit already?

No, it means that you are virtually guaranteed to have a ring.

It's also virtually guaranteed to be wired in 2.5mm² cable.

As a radial there's a very good chance you could have a 20A breaker, and a reasonable one that you could have a 25A one. You need an electrician to check how the cable has been installed, unless you know the details of the route? e.g. is it in thermal insulation anywhere, or in a bunch with other cables?

 

[bengasman]

Stumbled onto this thread when looking for an answer to another issue and am a bit puzzled why you can't take a 16A spur from a 32A ring as long as the cable to the spur is big enough to carry 32A.
What am I missing?

 

[ban-all-sheds]

It's not allowed. The cable in a 32A ring final is too small to be on a 32A breaker, but there's a special dispensation (aka kludge) to allow this provided certain conditions are met. One of which is that it shall only supply BS 1363 accessories, i.e. sockets and FCUs. You can't get 16A fuses for FCUs.

 

[JohnW2]

Stumbled onto this thread when looking for an answer to another issue and am a bit puzzled why you can't take a 16A spur from a 32A ring as long as the cable to the spur is big enough to carry 32A. What am I missing?

For a start, I'm not sure what you would mean by a '16A spur' - since the largest fuse you could put into an FCU is 13A - the only way you could do it would be with an MCB in an enclosure or a switch-fuse (neither of which would be allowed on a ring final).

As for connecting a 16A load to a 32A ring final circuit, the whole concept of such a circuit assumes that the 32A maximum load is reasonably distributed around the whole of the ring - and applying a 16A load at one point on the ring clearly goes against that concept. More practically, if there is one load that large attached to a ring, it doesn't leave all that much for 'everything else'.

Kind Regards, John

 

[bengasman]

Why would you need a separate fuse on a circuit that already is protected by the mcb or other form of fuse on the board? I may have missed it but I'm not aware BS 7671 require more than one fuse to protect the wiring.

Apart from that, I can get 16A as well as 20A ceramic cartridge fuses without any problem from stock.

Why would cable on a 32A ring be too small to carry 16A from a 'spur'?

Not saying you're wrong, just that I'm at a loss as to the why and how.