Protecting 2 ovens on 1 radial cicruit

[Hefferl]

I need to install 2 single ovens (3.45kw / 14 odd Amps each).

I only have one way available in CU.

If I use a single radial circuit on a 32A MCB how can I comply with this manufacturer's installation instruction "The fuse protection must correspond to the power rating specified on the appliance's rating plate and to local regulations"?

My options appear to be 

(1) Don't protect them just protect the circuit cable

(2) Use a 13A FCU

Suggestions please.

 

[Essex1]

Manufacturers have no place telling you what to do with your own installation. Crack on with the radial. 

 

[Rob_the_rich]

I have two thoughts on this;

(1) BS7671 134.1.1 says "The installation of electrical equipment shall take account of manufacturer's instructions", ie "take account" not blindly follow.

(2) MI says must "correspond", not "exactly equal". The corresponding protective device for a 3450W oven would be 15A or higher (not "14 odd amps", you divide by 230, not 240) depending on the type of device.

 

[binky]

if you have protected the cable properly, then it complies with regs. If you are worried about overloading the supply, then that is highy unlikely as the ovens won't run at full power except when getting upto temp.

 

[leesparkykent]

I would run a 6mm 32A radial (cable calcs depending) with a dual cooker outlet plate.

 

[Hefferl]

I am taking account and not blindly following the MI - if I was blindly following I wouldnt be considering option 1.

But also I'm not just ignoring them and thats why I posted the question to see if there was a way to achieve this.

I do realise that the device needs to correspond and not be exactly equal - but my point is that with a 32A radial the device will not correspond with the power (15A or so) of an individual oven and as such will only protect the cable and not the appliance as the manufacturer asks - and whether to divide by 230 or 240 depends on what voltage the power rating is quoted at surely?

I am not worried about overloading the supply as the two ovens combined will not exceed the MCB/Cable rating.

I guess I could run the radial to a small enclosure with 2 x 16A MCBs - but the general concensus appears to be that If I correctly protect the cable I have done enough so thats what I shall do - many thanks to all,

 

[Sidewinder]

Under the Low Voltage Directive the manufacturer is forbidden to rely on the circuit protective device in the installation to protect their appliance.

Now, if they are, then the equipment is not legal for sale.

 

[Hefferl]

Under the Low Voltage Directive the manufacturer is forbidden to rely on the circuit protective device in the installation to protect their appliance.

Now, if they are, then the equipment is not legal for sale.

Great answer - thanks

 

[binky]

Under the Low Voltage Directive the manufacturer is forbidden to rely on the circuit protective device in the installation to protect their appliance.

Now, if they are, then the equipment is not legal for sale.

so every appliance should be fused?

 

[Sidewinder]

Not necessarily, it depends on the detail design and, the product standard.

It is not necessary to fuse the appliance to make it safe.

It is just that the protective device in the supply installation is ONLY there to protect the installation itself, not, any appliances connected to it in any way means, shape or form.

 

[Sharpend]

So why don't the manufacturers come up with the 16a fused plug?

 

[Andy™]

cheaper to print a bit in the book saying you have to provide it in the circuit

 

[Sharpend]

Oh I don't disbelieve that, but how much better would this planet be to live on if we all worked together rather than against each other! 

 

[mikep]

Why not 32a radial with a a small BG ip65 CU with 2 x 16a Mcb's in the kitchen may be the best thing you can do cheaply !

£32 BQ

 

[Sidewinder]

Ensure it's a non-combustible CU remember!

Not many IP65 non-combustible CU's out there.

The one I have found is an Al alloy, and I've yet to find out if it contains any magnesium.

 

[mikep]

British general do all metal ip65 shower and garage consumer unit available from Screwfix & B&Q, its really nicely made for the £32 it cost, comes with 63a RCD and 2x Mcb's,, I've fitted a few of them in the kitchen base units using the old 45amp 10mm cooker to feed them then you have a 3 way Mcb's  and RCD unit for running ovens & hobs etc for £32 or £27 for the Garage one but a 40a Rcd fitted, perfect !

 picture below

 

[Sidewinder]

British general do all metal ip65 shower and garage consumer unit available from Screwfix & B&Q, its really nicely made for the £32 it cost, comes with 63a RCD and 2x Mcb's,, I've fitted a few of them in the kitchen base units using the old 45amp 10mm cooker to feed them then you have a 3 way Mcb's  and RCD unit for running ovens & hobs etc for £32 or £27 for the Garage one but a 40a Rcd fitted, perfect !

 picture below

View attachment 7027

They are an aluminium based alloy, though, thus not ferrous, e.g. steel, and if, they contain any, magnesium, then they are in contravention of the requirements of buildings standards.

I have yet to get confirmation of the exact scenario, hence why I have not used them.

Until I do have confirmation of the metallurgical composition of the alloy, and can prove that if, it contains magnesium, it is still compliant, in a truly traceable manner, then I will not be using them.

 

[kerching]

I remember back in the day being called to a fire in a switch room.

aluminium cased check meter had got a tad hot due to a very loose connection. The end result was less than desirable

 

[Rob_the_rich]

Under the Low Voltage Directive the manufacturer is forbidden to rely on the circuit protective device in the installation to protect their appliance.

Now, if they are, then the equipment is not legal for sale.

Bathroom fans requiring 3A fuses?

 

[Sidewinder]

They shoud not be doing it, but, like most things it's not policed.