220v. 230v, 240v, 250v?

[John-SJW]

I saw an oven that was rated at 3,100 watts. Now most would say that cannot be fitted on final ring circuit as rule of thumb. But:
3,100 watts draws amps of:
14.09 amps @ 220v
13.47 amps @ 230v
12.91 amps @ 240v
12.4 amps @ 250v

If the installation is 240v or 250v then it safely inside the 13 amp of a final ring circuit.

The question is, and the regs aficionados can help here, what is the voltage that should be used to assess, as maybe the voltage will vary in an installation over the years.

 

[Julie.]

.....I would have thought provision would have been made by the manufacturer to have such a heater in constant use.

It depends on the instruction manual with the device, they almost all give instructions "suitable for a normal room up to 6m^2" or something similar.

This isn't just buff, it's limiting the use to a place where it can maintain the typical temperature whilst remaining within the duty cycle it's designed for!

If you want a device that may be operated continuously, then you need to buy a suitable device.

 

[ipf]

It depends on the instruction manual with the device, they almost all give instructions "suitable for a normal room up to 6m^2" or something similar.

This isn't just buff, it's limiting the use to a place where it can maintain the typical temperature whilst remaining within the duty cycle it's designed for!

If you want a device that may be operated continuously, then you need to buy a suitable device.

Of course.....but tell that to a cold bunch of old codgers in the room, including 'acting caretakers'.?

 

[ipf]

I think a lot of the problem is some of the cheap plugs that are around these days. Bring back the old MK ones with proper knuckled terminal screws with built in washers. Lovely!

What do you mean, they were a nightmare..................with T+E.

 

[DPG]

Thanks for correcting my post mods!

 

[John-SJW]

Had a lady two weeks ago with gas hob and electric oven all controlled with normal cooker point, she wanted to change the hob to electric, no problem, she buys new Bosch induction hob, and I go there with a click dual outlet cooker outlet and some 4.0mm flex to connect it all up.
When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug

That seems very light. Mine is 7,200 watts.

 

[DPG]

That seems very light. Mine is 7,200 watts.

I think that's more of a 'normal' figure, but they do lower power induction hobs that will run from a 13A plug.

 

[John-SJW]

Had a lady two weeks ago with gas hob and electric oven all controlled with normal cooker point, she wanted to change the hob to electric, no problem, she buys new Bosch induction hob, and I go there with a click dual outlet cooker outlet and some 4.0mm flex to connect it all up.
When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.
Did not seem the right thing to do but to date have had no call backs, I do have to go there to do some other work shortly and will check it out and see how it is performing.

Many instruction have a get out clause (for them) of see a competent electrician. In short, he does what he thinks is fit. I would never have connected a hob to 13A plug, irrespective of what the manufacturer sent it with. It is a matter of doing it safely, not covering your rear end - or believing them (some dodgy, and vague, instructions out there from many makers).

 

[nicebutdim]

My "Morphy Richards" kettle is 3kw.It has a lead that is max 3x1.5mm (but probably 1mm. Moulded plugtop so can't check) .Before energy saving appliances came on the scene it was normal to have washing machines, driers etc up to 3.5 kw, all connected with 13amp plugs and usually 1.5 flex. A 1.5mm flex can comfortably handle a continuous current of 13 amp (and above). The key difference between appliances of the same wattage is whether they are designed to be used intermittently (kettle) or in a more sustained way (space heater). A sustained load should really have its own circuit.

Some interesting examples following this post.

My parent's utility room used to be served by a single spur (rubber cable roughly equivalent to 2.5, on 30A circuit), to which someone had fitted a 4 gang unswitched socket that had been lopped off an extension lead. Oddly enough this never caused any issues, although that was likely due to my mother having the good sense to only use one appliance at a time, alongside the freezer.

I still break out in a cold sweat when I think of what passed for wiring in that house.

 

[telectrix]

Some interesting examples following this post.

My parent's utility room used to be served by a single spur (rubber cable roughly equivalent to 2.5, on 30A circuit), to which someone had fitted a 4 gang unswitched socket that had been lopped off an extension lead. Oddly enough this never caused any issues, although that was likely due to my mother having the good sense to only use one appliance at a time, alongside the freezer.

I still break out in a cold sweat when I think of what passed for wiring in that house.

that's nothing.my mam used to have an iron that plugged into the kitchen light via an adapter. that's once she'd learnt not to stand it on the fire iron.

 

[littlespark]

This is starting to sound like a Python sketch again......

 

[telectrix]

This is starting to sound like a Python sketch again......

it's only a flesh wound.

 

[ipf]

Thanks for correcting my post mods!

wondering what a knuckle screw was ?

 

[ipf]

This is starting to sound like a Python sketch again......

Flowery Tw*ts in 10 mins on BBC1.
Manuel with his pet 'hamster'.

 

[Julie.]

This is starting to sound like a Python sketch again......

Oh no it isn't.

 

[Dave OCD]

I think a lot of the problem is some of the cheap plugs that are around these days. Bring back the old MK ones with proper knurled terminal screws with built in washers. Lovely!

As a young apprentice with the local Health Authority I fitted dozens of these, lovely plugs and it brings back memories. Nobody ever questioned why my gran's twin tub had 'Hospital Property' embossed on the lid of the plug,or should that be plug top. ?

 

[westward10]

MK would brand plugs for people on a raised circular part on the cover I had loads with BBC on them.

 

[John-SJW]

Had a lady two weeks ago with gas hob and electric oven all controlled with normal cooker point, she wanted to change the hob to electric, no problem, she buys new Bosch induction hob, and I go there with a click dual outlet cooker outlet and some 4.0mm flex to connect it all up.
When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.
Did not seem the right thing to do but to date have had no call backs, I do have to go there to do some other work shortly and will check it out and see how it is performing.

This is playing on my mind as the appliance is capable of drawing over 13 amps. If the appliance came with no 13A plug, an electrician would not fit one on this appliance, as it is capable of drawing over 13 amps. Or fit it on a final ring circuit. It is obvious the makers have taken diversity into account, as the load is split between four current drawers, the rings, which will be cutting in and out via thermostats.

This makes me think that the combination oven (microwave and oven in one) example I mentioned at the beginning of this thread at 3,100 watts is suitable for 13A plug and final ring circuit. The instructions do not mention anything about amperage, I posted them, only that a DP isolator needs to be fitted. A 13A sockets have DP isolation. A spur off a ring with 20A DP isolator switch, or a 13A FCU, feeding a 13A socket behind the oven would conform to that.

Yes, I know it is best the oven has its own dedicated supply to be sure, that is not the point. Many would like to fit an oven like this, marginally over the 13 amp cut off point, as it would save ripping a finished kitchen to pieces.

 

[LastManOnline]

Had a lady two weeks ago with gas hob and electric oven all controlled with normal cooker point, she wanted to change the hob to electric, no problem, she buys new Bosch induction hob, and I go there with a click dual outlet cooker outlet and some 4.0mm flex to connect it all up.
When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.
Did not seem the right thing to do but to date have had no call backs, I do have to go there to do some other work shortly and will check it out and see how it is performing.

How many rings did that hob have?

 

[Lucien Nunes]

When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.

3700W requires a 16A supply. The hob probably has internal power management setttings to allow the total load to be limited to 16, 13 or 10A which should be set during commissioning. The rating given on the box is 3700W because that is what the hob is physically capable of delivering.

If you scroll down to the 'installation' tab on this link, Bosch have shown the 3700W limit as corresponding to the 13A plug version. I suspect that is a copy-and-paste mistake from the 16A Schuko-plug version and that they do not intend a 13A plug to supply 3700W.

PUE611BF1B Induction hob | Bosch GB

PUE611BF1B Induction hob | Bosch GB

www.bosch-home.co.uk

 

[John-SJW]

NEFF T36FB41X0G
BOSCH PUE611BF1B
SIEMENS EU631BEF1B

All four ring 13A induction hobs.

 

[John-SJW]

3700W requires a 16A supply. The hob probably has internal power management setttings to allow the total load to be limited to 16, 13 or 10A which should be set during commissioning. The rating given on the box is 3700W because that is what the hob is physically capable of delivering.

If you scroll down to the 'installation' tab on this link, Bosch have shown the 3700W limit as corresponding to the 13A plug version. I suspect that is a copy-and-paste mistake from the 16A Schuko-plug version and that they do not intend a 13A plug to supply 3700W.

PUE611BF1B Induction hob | Bosch GB

PUE611BF1B Induction hob | Bosch GB

www.bosch-home.co.uk

It says:

This hob is equipped with a UK 3 pin plug for an easy plug & play installation. The plug limits the maximum power output to 3.7 KW. For higher power output, please select a hob without plug and ensure installation is carried out by a qualified electrician

The 13A UK plug limits the maximum to below 3.7 kW - I think a mistake here in the writing.

 

[DPG]

It says:

This hob is equipped with a UK 3 pin plug for an easy plug & play installation. The plug limits the maximum power output to 3.7 KW. For higher power output, please select a hob without plug and ensure installation is carried out by a qualified electrician

The 13A UK plug limits the maximum to below 3.7 kW - I think a mistake here in the writing.

Agree, it seems like badly worded English.

 

[John-SJW]

Agree, it seems like badly worded English.

That is why I say use your judgement, not always going by the makers instructions.

 

[Lucien Nunes]

The 13A UK plug limits the maximum to below 3.7 kW - I think a mistake here in the writing.

Indeed, as I pointed out in post #59.

NEFF T36FB41X0G
BOSCH PUE611BF1B
SIEMENS EU631BEF1B

All four ring 13A induction hobs.

Bosch, Neff and Siemens are different brands of the same company, so I would expect to find those three hobs to be internally the same core product.

 

[DPG]

That is why I say use your judgement, not always going by the makers instructions.

Yes, but you can see the intention of what they mean.

 

[John-SJW]

My Smeg can be single or three phase.

 

[John-SJW]

Yes, but you can see the intention of what they mean.

That still needs judgement.

 

[John-SJW]

This 3,700 watt hob on a 13A plug, I am certain was a power adjustable version, with the makers not going by diversity. An assumption by me - the UK version with a plug would be factory set to 13A max.

 

[LastManOnline]

It says:

This hob is equipped with a UK 3 pin plug for an easy plug & play installation. The plug limits the maximum power output to 3.7 KW.

Interesting comment from the manufacturer, bearing in mind the 13amp fuse is installed primarily to protect the CABLE supplying the hob.

The 13A UK plug limits the maximum to below 3.7 kW - I think a mistake here in the writing.

13amp plug limit maximum? Unlikely. A 13 amp plug may well carry a few amps above its rating for a significant period

 

[John-SJW]

Interesting comment from the manufacturer, bearing in mind the 13amp fuse is installed primarily to protect the CABLE supplying the hob.


13amp plug limit maximum? Unlikely. A 13 amp plug may well carry a few amps above its rating for a significant period

Yes, fuses blow at above 13A, and only when sustained over-current is being drawn. It is a bad design that relies on the fuse not blowing.

 

[John-SJW]

Had a lady two weeks ago with gas hob and electric oven all controlled with normal cooker point, she wanted to change the hob to electric, no problem, she buys new Bosch induction hob, and I go there with a click dual outlet cooker outlet and some 4.0mm flex to connect it all up.
When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.
Did not seem the right thing to do but to date have had no call backs, I do have to go there to do some other work shortly and will check it out and see how it is performing.

Was this to a cooker radial 6mm cable? On on a final ring circuit? If on cooker radial, the plug could have been removed with the hob set to 3.7 kW drawing 16A.

 

[Lucien Nunes]

Interesting comment from the manufacturer,

But I think we have a concensus that this is a mistake.

Agree, it seems like badly worded English.

Achtung!
The Kookerhob is greatpowerneeding and the elektrische Kabels have to be placed bei the Skilledtechnician. In Europe is to make 16A Kuppling with a Schukostecker allowed. In Grossbritannien, because the dumme Plugtoppen the Weakcontacts and Stupidlittlefuses which like Heatelements often the Outburning or Downmelting are the cause of are required to have, is max. 13A permitted. Offchoppen von Plugtoppen is ABSOLUT NICHT GESTATTET!

 

[John-SJW]

But I think we have a concensus that this is a mistake.

By Bosch as well.

 

[littlespark]

But I think we have a concensus that this is a mistake.


Achtung!
The Kookerhob is greatpowerneeding and the elektrische Kabels have to be placed bei the Skilledtechnician. In Europe is to make 16A Kuppling with a Schukostecker allowed. In Grossbritannien, because the dumme Plugtoppen the Weakcontacts and Stupidlittlefuses which like Heatelements often the Outburning or Downmelting are the cause of are required to have, is max. 13A permitted. Offchoppen von Plugtoppen is ABSOLUT NICHT GESTATTET!

Thanks, Buzz... that makes perfect sense...


Oh.. it wasn't Buzz??

 

[telectrix]

But I think we have a concensus that this is a mistake.


Achtung!
The Kookerhob is greatpowerneeding and the elektrische Kabels have to be placed bei the Skilledtechnician. In Europe is to make 16A Kuppling with a Schukostecker allowed. In Grossbritannien, because the dumme Plugtoppen the Weakcontacts and Stupidlittlefuses which like Heatelements often the Outburning or Downmelting are the cause of are required to have, is max. 13A permitted. Offchoppen von Plugtoppen is ABSOLUT NICHT GESTATTET!

in myold house, back in the 70's the fuse box ( wylex with 3036's) was labelled "Achtung. Gerfingerpoken Verboten".

 

[Sparky Pat]

How many rings did that hob have?

4

 

[ipf]

But I think we have a concensus that this is a mistake.


Achtung!
The Kookerhob is greatpowerneeding and the elektrische Kabels have to be placed bei the Skilledtechnician. In Europe is to make 16A Kuppling with a Schukostecker allowed. In Grossbritannien, because the dumme Plugtoppen the Weakcontacts and Stupidlittlefuses which like Heatelements often the Outburning or Downmelting are the cause of are required to have, is max. 13A permitted. Offchoppen von Plugtoppen is ABSOLUT NICHT GESTATTET!

Are you Stanley Unwin in disguise?

 

[Julie.]

in myold house, back in the 70's the fuse box ( wylex with 3036's) was labelled "Achtung. Gerfingerpoken Verboten".

I prefer a label like this:

 

[LastManOnline]

When we take it out of the box it is rated at 3700 watts and is factory fitted with a lead and 13 amp plug so as we are told to follow manufacturers instructions I then duly fitted a single socket to the cooker outlet circuit and plugged the Hob in.

Remember the terms "close excess protection" and "coarse excess protection" (not sure if they are used much any more). But manufacturers would be aware that most fuses are pretty crude devices. A 13 amp fuse will happily carry 15,16 amps for more than enough time than it takes to cook your chicken in an ovan or have fry your chop and boil your spud

 

[LastManOnline]

I would never have connected a hob to 13A plug, irrespective of what the manufacturer sent it with. It is a matter of doing it safely, not covering your rear end - or believing them (some dodgy, and vague, instructions out there from many makers).

"Manufacturers instructions". Well that deserves a thread all of its own. The intent is correct. Who knows an appliance better than its maker.? But like everything, it's open to abuse. The solution in my view is proper scrutiny. Instructions without explanations is always a bad idea. Some manufacturers clearly see it as a blank cheque.