UKH

I'm in the market for a range oven. Needs to be wide to fit the space.

I have my eye on this one: https://www.currys.co.uk/products/logik-lftg90b18-90-cm-dual-fuel-range-coo...

Issue is I only have a gas supply and a 13a fused socket on a switchable spur.

I really don't want to go down the route of adding a 16a radial. It's a long way and not an easy route and would be quite a lot of disruption.

What I'm not sure about is it's rated for 3000w yet needs a 16a fuse.

Any idea why this is?

How naughty would it be to use a three pin plug?

I know it will work just fine, but don't want to cause trouble later when selling for example.

No

13A plugs and sockets are not designed to be run at 3000w for extended periods regularly. You may start a fire. Especially if you are tight and bough cheapo sockets/plugs. And no, the fuse won’t prevent this. 

don’t do it.

however, if you contact a local sparky you may find your fused spur is heavy duty enough for a direct 16A connection. Or not. But it’s worth asking.

13A plug though.. no. If that was safe they would have provided one. End of.

Not sure why you've replied to me, I already said I wouldn't do it!

I take your point, and reading your response has helped me understand their logic (see below). But I still think it would be safe under normal use. I can buy a 3kw heater (in fact I have one for the attic) and run that off a 13a plug all day long. Whether you should is another matter, but all the checks and balances do not prevent consumers from doing this.

In order to draw 3kw from the cooker for an extended period, I would have to have the grill and the oven on and leave the door open, otherwise it would likely only stay on for 10 minutes before the thermostat kicks it off.

This is the scenario I suspect they are thinking of and hence the 16a requirement.

Does it not often just come down to manufacturers wanting a product for worldwide markets.

Take a 2.2kw unit (https://www.currys.co.uk/products/kenwood-ck306-90-cm-dual-fuel-range-cooke...) which says "13 Amp (Requires hardwiring to a fused spur)"  which i don't believe to be true. 

A 13a Oven can perfectly legitimately be connected to a three pin plug.

But I may have to get the more expensive one linked above.

Any thoughts wiring this one to a plug. Surely the text on their website isn't for any UK requirement. Although just as easy to hard wire this one as I have the 13A spur anyway.

Assuming good parts well fitted: 

Question 1: Over what time does a 13A fuse reach thermal balance between ohmic heating from the fuse and heat loss to the environment.

Question 2: Is is more or less than the boil time of a typical kettle?

Regardless of the answers, I’d be concerned that the single-core, oval profile 6242 twin & earth on an oven can’t be safely fitted to a 13A plug for couple of reasons, and so it’s fundamentally not going to make a safe plug for any power draw.

Because I’m a lazy bum and usually reply to the most recent post.. 

It's the 3kw heaters you would need to worry about.

I hadn't considered this.

I've not found the original source yet (assume it's law) but it seems there's a requirement that a fixed unit should be hard wired if above 2kw, and 13a otherwise.

Trying to understand the logic here, but I guess it's unlikely that a mobile heater is going to be used on the same socket for 20 years.

Exactly. Although my granny definitely did this. The socket in question was brown and crumbly when we got to it after she went hee own way. I think that’s the point here.. also it’ll be inaccessible so you can’t monitor it. 

Also on a purely pragmatic point, if you go against the manufacturers instructions and or the law, your home insurance will be invalid. 

Probably the most important point.

Fine, I'll get a gas cooker. But don't blame me when the cake doesn't raise properly due to uneven heat.

Sorry.. You can’t have your cake and heat it (evenly)

Doesn't matter what we think,  what do the manufacturers installation instructions say? Follow them.

It'll be fine. What's the worst that could happen?

But if you don't question and challenge things and ask questions you don't learn.

To answer your thread title, yes, I would if it was mine. Would I do it for anyone else? No.

It's interesting that no one will countenance this on this thread, but every time we have a thread about EV charging someone will say they have been using a granny charger for years. That's about 2.8kW for 10 hours straight, so a bigger risk than your oven. 

Hard wired ovens don't usually come with a cable only a junction box. You can get 16A flex that fits perfectly fine into a plug so if you use this  your last point isn't really an issue.

Might be a bigger risk in the first 10 hours - but a granny charger's generally out in the open with some ventilation and you can see if the cable/plug starts to show any damage over the years.

Oven is either built in or in a custom gap with the cable & plug hidden. You can't see if there's sufficient ventilation to stop the repeated heat stress from possibly inadequate ventilation causing any long-term damage, especially remembering that an oven does tend to put out rather a lot of heat.

So presumably requiring higher spec wiring is to build in some contingency for that hidden degradation over time.

Isn't there a wider point that the entire ring circuit becomes overloaded if it's not a dedicated circuit? E.g, kettle plus oven plus toaster.

3000W / 240v = 12.5A

Way too close for a 13A fuse which will give loads of nuisance tripping

A BS1362 13A fuse will never blow with a current of 20A.

See bs1362 fuse characteristics/time-current curves for further reading.

How very british. 

The specification actually says 3.3 kW, which would require 13.75 amps at unity power factor. However the load is likely to have an inductive component giving a less than unity power factor so the actual current could be significantly greater, particularly at switch on, hence need for a 16amp fuse. But at least you will save on house insurance as there wouldn’t be any point in buying policy that may not be honoured.

The article I found on searching that makes the point that the 13A fuse rating is the maximal continuous load at which the *fuse* will not cause thermal damage to the plug. Fuses work by running hot and then melting. By running AT the spec load long term you are basically operating at the thermal design limit of the plug/socket. This is not wise..

As noted, the granny charger (and actually the ‘3kw’ heater are more like 2.8 and this margin is important. The only device you probably have which is *actually* 3kw is your kettle which doesn’t run for long.

buy an air fryer…..they bake excellent cakes as well.

It doesn’t matter what anyone ‘thinks’, you can do what you like. However when you come to sell the property, the surveyor will flag up that it fails to have a dedicated double pole switched spur from the consumer unit at the manufacturers stated required rating, and also you won’t have the sign off of a qualified electrician for part P, for a plug into a 13A socket.

As it fails to meet the fitting instructions posted by the retailer and presumably the manufacturer, if there happened to be a fire there’s a strong possibility that your house insurance will be null and void.

If you aren’t part P qualified, it probably voids the manufacturer warranty also. Finally, it’s your home where your family lives, why not do it properly?

People keep saying this. What is the basis? There is nothing in my insurance documents mentioning any such requirement and pretty much all houses will have something that isn't compliant with current (i.e contemporary not electric!) regulations 

Insurance policies are likely to exclude damage caused by wilful negligence by the home owner / policy holder. I would expect fire caused by DIY electrical work in contravention of wiring regs could come under this

Yes, I can see identifying a potential problem, asking for advice on the internet and then ignoring it might not look good!  A bit different to a historical situation that was overlooked.

https://www.directline.com/assets/pdf/dl-home-insurance-policy-document.pdf

Specifically page 7 - policy conditions - this policy doesn't cover:

• Faulty workmanship, faulty design or the use of faulty materials.

After a little more digging, there is no requirement that I can find for fixed appliances over 2KW to have their own dedicated circuit.

Part P doesn't appear to mention it.

There's guidance in Appendix 15 of BS 7671 that anything over 2KW should have a dedicated circuit, but it's not a requirement.

This, is I expect why appliances that are fixed over 2kw don't have a plug as they don't want to be encouraging customers to do something not recommended by BS.

So the 2.2KW unit would appear to be within the regs if on a 13a plug.

Don't try to wriggle out of it, someone has to be randomly blamed, it's how all forums work 🤣

Just clicked the link in your original post and read this:

"ELECTRICAL INSTALLATION: This product requires professional installation to a dedicated circuit by a qualified installer, such as one of our Tech experts. Our expert installers may be able to install to a dedicated cooker circuit (identified by a big red cooker switch) if you do not have a 16 Amp supply in your home."

If you plug it into a socket with a 13amp fused plug you're on your own with your house insurer if there is any kind of electrical fault that causes a fire in your house!

Wow betide anybody who ignores guidance in standards!

a general rule of thumb is ‘if it comes with a cable and a plug fitted, then it’s ok to plug it in’. My guess is that if i’d does come with a cable, it’ll be a 1m long tail to go to a terminal box. So that would be a no.

This is such a UKC classic thread 😁😍

my guess is that running a new 16A circuit would cost maybe 1/1000 of the value of an average house.

Not ignoring. Acknowledging and then doing something different.

Understand. Sometimes you just have to bite the bullet and follow the guidance despite it being a  pain. After all in a few years time that guidance will probably change to a requirement anyway. 

I've already said upthread I'm just going to get a gas oven. Too much work involved running the radial.

A, um, 'friend' of mine used this to charge his electric car, via a long extension cord strung across the garden.  Two fried outdoor sockets later [took about 8 months each time, and  one time it welded the plug to the socket], the, uh, friend... learned that the incoming amps could be dropped using the charging app.  So, running it at, say, 6 amps is not frying anything, no more random circuit breaker tripping either. 

Here are some considerations;

• how do you even know that the wiring in your house was done by a competent person?
• what else is on the circuit ? dishwasher, washing machine, boiler?
• how do you know what circuit type it is radial or ring? 
• when was the wiring done for your house? multiple white goods in one location wasn't a thing 20+ years ago plus the standards and building regs have changed a lot. 
• what other cables run in the same space as this circuit? Combined heating effects will add up, this changes resistances which changes trip times. 
• is this circuit protected by an RCD / RCBO how do you know its sized appropriately ?
• adding a socket for an oven requires RCD protection [building regs P]
• ovens less than 2kW can be connected onto a ring [building regs part P] 
• what depth are the cables installed at ? 
• a new circuit is notifiable work 

We had that issue and ran a cable outside the house from the fuse board to the cooker. We even buried the cable

That was a good rule until certain online marketplaces started selling absolute junk with no safety certification that fits a UK socket.  Some off the stuff of them is lethal including sub-standard plugs and sockets (on extension leads) with fake shutters giving no safety etc.

We have a central chimney that the cooker is against so we would need to get it to the middle of the house.

We've tried running cables through the cavity wall before to get to the attic but had to go outside in the end.