Wiring for new 16 Amp oven

[Beeg]

Evening all, apologies if this is in the wrong forum or has been asked before.

I have ordered a new oven thinking I could just plug it in to 13amp socket same as my old one. However I checked today and the oven is 16amp and therefore should have its own dedicated circuit.
I checked the instructions for the old oven and turns out that is also 16amp, however it has been connected to 13amp socket.

I understand that using 3 core flex to connect the new oven to a 3 pin socket does not conform to regulations, and I do not intend on doing so.
But if the plug was fitted with 13amp fuse, would this not adequately protect the cable from over current? Assuming the oven was at full load and drawing 16amps, would the plug top fuse simply blow causing a minor annoyance at dinner parties?

I must stress again that I have no intention on doing it this way, I just have a keen interest in electrical theory and want to know for my own satisfaction

Thanks in advance
Beeg

 

[SparkyAndGeorge]

what does the manufacturers instructions say? sometimes it states categorically NOT to put it on a plug

 

[Tony Reidy]

You are right it does need a dedicated circuit

 

[James]

it may well work just fine, 16A will be the current draw whilst every element is on at the same time. however I WOULD NOT RECCOMEND doing so.
note, the time the fuse will blow is in the middle of cooking x-mass dinner, when the fuse is warm from being under load for a long time and you turn everything up to finish it off.

sods law and physics working in harmony.

Dedicated circuit is the way forwards.

 

[Tony Reidy]

what does the manufacturers instructions say? sometimes it states categorically NOT to put it on a plug

But are they implying that a 13A switched spur is ok

 

[Octopus]

What is the make and model of the oven ?

 

[James]

But are they implying that a 13A switched spur is ok

16A is the key,
standard 13A plug is a no
13A spur is a no
16A socket could be done
16A isolator is ok.
simple, supply has to be greater than manufacturer's instructions.
No If's, No buts. if you want it to comply and be safe, follow the manufacturers instructions.

 

[Tony Reidy]

16A is the key,
standard 13A plug is a no
13A spur is a no
16A socket could be done
16A isolator is ok.
simple, supply has to be greater than manufacturer's instructions.

I do think it should be made clearer to customers when they buy an oven

 

[Wilko]

Hi - as above, use manufacturer’s installation instructions as your guide. No plug and socket for a 16A oven please. By the by, a 13A fuse won’t melt at 13A as that’s it’s rated working current. What we perhaps can’t be sure of is what size flex is used. So the fuse will protect against a short circuit, but maybe not a small (but long term) overload. There are fuse current vs time graphs around if you’d like to dig further .

 

[Beeg]

Thanks everybody.

I suspected it wasn’t right, even though the existing one is 16amp connected to a wall socket.

I haven’t had chance to look but did wonder if it was possible that the socket was on a dedicated 16A radial circuit , but as I understand it the socket would only be rated to 13A? And even then the safety of the cable is relying on the fuse blowing in time?

Apologies if that’s a load of bo****ks ^^

 

[Charlie_]

Have a look at the rating plate of the oven. What is the power rating?

 

[Beeg]

Have a look at the rating plate of the oven. What is the power rating?

3.2kw. Therefore 3200/230 = 13.9 A?

 

[Octopus]

What is the make and model of the oven ?

I’ll try again ....

 

[Beeg]

Hi - as above, use manufacturer’s installation instructions as your guide. No plug and socket for a 16A oven please. By the by, a 13A fuse won’t melt at 13A as that’s it’s rated working current. What we perhaps can’t be sure of is what size flex is used. So the fuse will protect against a short circuit, but maybe not a small (but long term) overload. There are fuse current vs time graphs around if you’d like to dig further .

Just had a quick look at the current v time graphs and apparently a 13A fuse can have 20A through it and not blow

 

[Beeg]

I’ll try again ....

My apologies. It’s a
AEG BES351010M

 

[Octopus]

Well .... the mi says 16a

So a dedicated circuit required ...

 

[Octopus]

Well .... the mi says 16a

So a dedicated circuit required ...

 

[Beeg]

Well .... the mi says 16a

So a dedicated circuit required ...

I agree, as I said before I had no intention of doing it any other way, I just wanted to satisfy my own curiosity about the potential consequences of connecting to a standard 3 pin plug / socket. Thanks for your help

 

[James]

It is not something you can say “it’s only a little over”
The limit is 13A, not 13.2A not 13.05A
13A IS THE MAXIMUM.
End of discussion.

 

[Octopus]

I agree, as I said before I had no intention of doing it any other way, I just wanted to satisfy my own curiosity about the potential consequences of connecting to a standard 3 pin plug / socket. Thanks for your help

Rule of thumb .... if it comes with a 13a plug on it, plug it in, if it doesn’t you need to hard wire it.

 

[Beeg]

It is not something you can say “it’s only a little over”
The limit is 13A, not 13.2A not 13.05A
13A IS THE MAXIMUM.
End of discussion.

I completely agree with you, as I said in my original post I had no intention of connecting to a 3 pin plug. I fully appreciate that the regs and max current ratings are there purely for safety and under no circumstances should they be exceeded.
I was merely asking to satisfy my own curiosity and I apologise for any confusion this has caused.

 

[Charlie_]

Also at 240+ volts the actual current and power will be higher than that stated for sure 230 volts

 

[Beeg]

Could be way off the mark here.... if the existing socket was off a RFC then the MCB would be rated at 32A.
Would it be possible / acceptable for an electrician to remove the existing socket and fit a cooker control unit, providing the cable to the oven is suitably sized, say 6mm?

 

[Taylortwocities]

Yes, you are way off the mark. It is not permitted to connect loads greater than 13A to a ring final.
All connections to ring final circuits must have a fuse of no more than 13A (usually a fused BS1361 plug or an FCU).

In fact, the guidance is that fixed loads of more that 2KW should be on their own dedicated circuit.

 

[Beeg]

Yes, you are way off the mark. It is not permitted to connect loads greater than 13A to a ring final.
All connections to ring final circuits must have a fuse of no more than 13A (usually a fused BS1361 plug or an FCU).

In fact, the guidance is that fixed loads of more that 2KW should be on their own dedicated circuit.

I didn’t think it would be as simple as that somehow so I either need to buy an oven under 2.9kW that has a plug fitted or get a sparky to run a new cable from the CU with a 16Amp MCB?

 

[Wilko]

I didn’t think it would be as simple as that somehow so I either need to buy an oven under 2.9kW that has a plug fitted or get a sparky to run a new cable from the CU with a 16Amp MCB?

Hi - the common approach for providing power to electric cooking appliances is by their own circuit. While the design can vary, its often a 6mm cable with a 32A overload protective device. The actual appliance connection method used is then varied to suit the appliance.
Are you saying you have no cooker circuit?

 

[Zerax]

It is not something you can say “it’s only a little over”
The limit is 13A, not 13.2A not 13.05A
13A IS THE MAXIMUM.
End of discussion.

Shame you weren't on our negotiating team for Brexit !

 

[dmxtothemax]

A 13A fuse will not blow at 16A.
At 25% overload will hold
At 50% over load will still hold, but may blow if held for long periods
At 100% will usually blow.

 

[Pete999]

Could be way off the mark here.... if the existing socket was off a RFC then the MCB would be rated at 32A.
Would it be possible / acceptable for an electrician to remove the existing socket and fit a cooker control unit, providing the cable to the oven is suitably sized, say 6mm?

NO

 

[Beeg]

Hi - the common approach for providing power to electric cooking appliances is by their own circuit. While the design can vary, its often a 6mm cable with a 32A overload protective device. The actual appliance connection method used is then varied to suit the appliance.
Are you saying you have no cooker circuit?

I do have a cooker circuit but as far as know that’s for the electric hob on the other side of the room.
So it could be that the socket isn’t part of the RFC but is actually fed from its own 32A MCB?

If that was the case would it be acceptable /conforming to remove the socket and fit a JB/cooker connection unit with some 6mm T&E to the oven?

 

[Wilko]

Hi - in that case I think you need an Electrician and a new circuit to suit. Someone here maybe able to help if you post up your locale .

 

[Beeg]

Hi - in that case I think you need an Electrician and a new circuit to suit. Someone here maybe able to help if you post up your locale .

Thanks Wilko, think I may just swap the oven for one under 3kW that can be plugged in, sounds less messy. I have solid floors so cables can’t be run underneath downstairs floorboards.

If the existing socket is supplied from its own circuit on 32A MCB, would an electrician just remove the socket and fit a cooker control unit with some 6mm T&E to the oven?

Thanks again

 

[James]

They might well do that but you need someone to actually come and look before quoting.

 

[davesparks]

Also at 240+ volts the actual current and power will be higher than that stated for sure 230 volts

This assumes the stated power rating isn't the 240V rating. Most heating elements are still built to the exact same spec as before this mythical voltage change so the published ratings of a lot of appliances are still the 240V ratings.
Electric showers are a good example, they usually have a nice big power rating on the box with small print stating the lower, less attractive, 230V rating.

 

[Beeg]

Thank you everyone for your replies and patience, it is appreciated.

Would I be right in thinking this is not a situation whereby a competent electrician would apply diversity?

Thanks again
Beeg

 

[telectrix]

Just had a quick look at the current v time graphs and apparently a 13A fuse can have 20A through it and not blow

but the Titanic could have 20 holes in it and not sink, but it did.

 

[telectrix]

Thank you everyone for your replies and patience, it is appreciated.

Would I be right in thinking this is not a situation whereby a competent electrician would apply diversity?

Thanks again
Beeg

my thoughts. stick iton a 13A plug. get a camp meter and see how much you can get the current up to by switching everything on. bear in mind the initial current will be higher than once it's started cycling on stats.

 

[telectrix]

meant clamp, not a poof meter.

 

[Octopus]

Thank you everyone for your replies and patience, it is appreciated.

Would I be right in thinking this is not a situation whereby a competent electrician would apply diversity?

Thanks again
Beeg

Apply diversity to what?

The manufacturer's instructions say 16a which means a dedicated supply ...

 

[Beeg]

my thoughts. stick iton a 13A plug. get a camp meter and see how much you can get the current up to by switching everything on. bear in mind the initial current will be higher than once it's started cycling on stats.

I understand the theory behind this, however would it not be a contravention of the regs as it is connecting something with a stated max load above 13amps to a 13amp socket/ring final circuit?

 

[telectrix]

as murdoch said. MI says a 16A supply, so that's what you need to do, even if it never pullls over 13A.

 

[Beeg]

I noticed something on another forum saying that it is possible to take a mini CU off the downstairs ring and fit a 16A MCB to it which would supply a cooker point.

So the 32A MCB at the main CU would supply downstairs ring plus a mini CU.

Am I right in thinking that the regs state nothing above 13amp may be connected to RFC?

 

[Wilko]

Hi - many things in life are possible, but some are not recommended.
AFAIK there isn’t really a regulation prohibiting this exactly, but IMHO it’s not in accord with Appendix 15 and perhaps Regulation 433.1 (design so that a small overload of long duration is unlikely).
Another way of saying it - if a student submitted this design at college it wouldn’t result in a pass.

 

[Pretty Mouth]

Beeg, the OSG advises this:

H2.5 Permanently connected equipment
Permanently connected equipment should be locally protected by a fuse complying with BS 1362 of rating not exceeding 13 A or by a circuit-breaker of rating not exceeding 16 A and should be controlled by a switch, where needed (see Appendix J). A separate switch is not required if the circuit-breaker is to be used as a switch.

So the IET have no problem with what you propose

 

[Beeg]

Hi - many things in life are possible, but some are not recommended.
AFAIK there isn’t really a regulation prohibiting this exactly, but IMHO it’s not in accord with Appendix 15 and perhaps Regulation 433.1 (design so that a small overload of long duration is unlikely).
Another way of saying it - if a student submitted this design at college it wouldn’t result in a pass.

Thanks Wilko. I’ve swapped the oven for one fitted with a 13amp plug but had I kept it, an electrician wouldn’t have connected it in the method described above and would have have insisted on installing a new radial circuit from the CU?

 

[Wilko]

Myself, I wouldn’t likely be putting a new remote CU for a cooker on top of a B32 RFC. If it needed it’s own B16 it would be sitting in the CU and feeding the appliance in the usual way. But that’s just me, I can’t comment on what someone else would do.

 

[Pretty Mouth]

That's fair enough Wilko, what you say would certainly be better practice. There are times when best practice is hard to achieve - no spare ways in the CU, expensive decoration, you know the sorts of things. It's nice to have other options which, while perhaps not ideal, will still get the job done

 

[Beeg]

Sorry to ask yet another question on this thread.
I’ve found an oven which is 13amp but it doesn’t come with a plug and says it must be hardwired.
Does anyone have any idea of the reason for this?
Is there any reason why a plug can’t be fitted to it?

Thanks again
Beeg

ETA... I appreciate that MIs should always be followed, I’m just intrigued as to why this might be the case.

 

[James]

Sorry to ask yet another question on this thread.
I’ve found an oven which is 13amp but it doesn’t come with a plug and says it must be hardwired.
Does anyone have any idea of the reason for this?
Is there any reason why a plug can’t be fitted to it?

Thanks again
Beeg

ETA... I appreciate that MIs should always be followed, I’m just intrigued as to why this might be the case.

They are not manufacturers instructions, just the advertised spec.