Siemens Appliances

[fester]

I have ordered a number of siemens appliances and whilst a new kitchen is being fitted, the power points are being planned accordingly.

The hob has a max working load of around 7Kw so I intend to use the old cooker cable. ?? dont know the mm2??

The cooker has max work load of 3.5Kw which I thought was a little over top but then, if literature says then literature right. So then I thought that at least the microwave would fit on the new ring main. Noooooo, literature says that the max work load is 3.5Kw,

So my question is, do I run two new circuits to new kitchen (after new ring main and new lighting circuit), one for oven & hob, one for microwave, p.s. it is the siemens quantum speed oven OR WILL THE 3.5Kw UNITS BE OK RUNNING OFF THE RING MAIN??????

 

[ban-all-sheds]

I have ordered a number of siemens appliances and whilst a new kitchen is being fitted, the power points are being planned accordingly.

The hob has a max working load of around 7Kw so I intend to use the old cooker cable. ?? dont know the mm2??

Perhaps you should find out. What is the rating of the MCB?

So my question is, do I run two new circuits to new kitchen (after new ring main and new lighting circuit), one for oven & hob, one for microwave, p.s. it is the siemens quantum speed oven OR WILL THE 3.5Kw UNITS BE OK RUNNING OFF THE RING MAIN??????

No, they won't - they are drawing 15A, and there's no practical way to connect them to a ring main.

You can (almost certainly) use the existing cooker supply for the hob, then put in 2 more 16/20A radials for the oven and microwave. Depending on the size of cable, you may be able to use the existing cooker supply to feed a mini-CU in the kitchen with 3 outgoing circuits.

 

[Adam_151]

You could do something like this:

The cables labled 6/10mm could be 6mm unless they are long or have derating factors applied, etc, ect, but for future proof it would make sense to have 10mm on at least one of them, if there is one 10mm and one 6mm it would make sense to have the hob one as the 10mm one, as it would be the main cooker circuit as opposed to the aux one, so if a all in one cooker was fitted in the future, or even if the hob was upgraded, the cable would be right, and most likely only the breaker would have to be changed, minising destruction of the walls.

I've drawn 15A round pin sockets for the oven and microwave so these can be unplugged for mantainance, etc, etc

Adam

P.S.
empty white boxes are cooker connection points
mini CU should go somewhere accessible, but not intrustive (eg.inside a cupboard)

 

[fester]

thanx for that. Have decided to rip the old cooker circuit out and install two new circuits. One for Hob at 7Kw and one for oven and micro at 3.5Kw each. Pretty much like your suggestion, thanx. Sparky mate of a mate who works for powergen did it for me. He also ran an earth cable whilst installing the new circuits so this could be attached to a new stop cock on a new plastic water main pipe (see my post in plumbing section). This earth wire is grounded at the electric meter where a new gas supply is also earthed.

 

[ban-all-sheds]

He also ran an earth cable whilst installing the new circuits so this could be attached to a new stop cock on a new plastic water main pipe (see my post in plumbing section).

Ooh - you don't want to do that....

 

[fester]

why not?? you got me worried now!!

 

[Scoby_Beasley]

Ooh - you don't want to do that....

Whats wrong with earthing a plastic pipe that (technically) doesn't conduct electricity ??

 

[ban-all-sheds]

Precisely that - the underground plastic pipe does not conduct electricity and therefore the metal pipe it joins to is not an extraneous-conductive-part.

Connecting it to the earthing system means that it could then provide a path through you if you touch it, and something live, and that it itself could become live in a fault condition.

OTOH, if you leave it alone it is no more hazardous than a metal curtain track - you wouldn't earth one of those, would you?

 

[Damocles]

Though static build up from repeatedly pulling the curtains could give you a nasty nip off that curtain rail. Better watch out.

As far as I can make out BAS is entirely correct that a plastic water pipe coming into a house is not an 'extraneous conductive part', which is the technical term for bit of metal going through your wall/floor coming out of the ground. Regulations specify that only 'ECP' have to be bonded. Sadly, the OSG specifically also states that if a plastic service comes into the house then it should be bonded where it becomes metal (if it does).

I say sadly because this rather goes counter to the official reasoning on earthing safety, which BAS also explained. The only justification I have seen is that the plastic pipe might unknown to you change very quickly into metal below ground. You need about 1m of plastic pipe to be absolutely guaranteed of electrical isolation (i think, might be less).

 

[plugwash]

the other problem is you have a large grid of metal pipe running through the house

this grid of metal pipe probablly runs rather close to a lot of cables......

furthermore this grid is likely to be earthed anyway though the bathroom bonding so giving it another tie to earth isn't really a problem.

 

[ban-all-sheds]

furthermore this grid is likely to be earthed anyway though the bathroom bonding so giving it another tie to earth isn't really a problem.

Shouldn't be - if the original point of entry of the water supply is plastic, then the pipes etc in the bathroom are not E-C-Ps, and therefore should not be part of a supplementary equipotential bonding arrangement.....