A few electrical questions

On 13/11/2010 20:28, dennis@home wrote:

A 4 ring hob would be cheaper... although 2.4kW is quite a sensible size to make them, in that at 10A each there is a reasonable chance a double socket would survive with two plugged in at once!
--
Cheers,

John.

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8<

The cheapest one I have seen is about £300 before fitting (you did notice that it was an induction ring?).
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On 15/11/2010 13:06, dennis@home wrote:

I can't see someone wanting an induction hob being satisfied with a pile of free standing ones. Still, nothing to stop you provisioning a circuit appropriate for four of them if that is what takes your fancy.
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Cheers,

John.

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I bought one, then discovered the pans were non-magnetic so it was useless without new pans. I bought a £1.99 wok from asda and that worked really well.. until I tried full power and it got so hot in a couple of seconds the oil caught fire.
I decided I wanted gas, its just better than electric for hobs.
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ROFLMAO
So you are calling the pans useless when it is in fact that it is you that is useless.

You are Frank Spencer AICMFP.
--
Adam



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Pitiful, isn't it?
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Today is Prickle-Prickle, the 27th day of The Aftermath in the YOLD 3176
"Always mount a scratch monkey."
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I suppose you can pick up a stainless steel pan with a cored bottom and know if it works on an induction hob from sight? And they predated induction hobs by a decade or two so there are no markings on them to indicate what they work on unlike newer pans. I chose the easy way, try them, how would you do it?
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wrote:

Induction hobs are described in Rankin Kennedy's 1909 'Electrical Installations' book
http://commons.wikimedia.org/wiki/File:Early_induction_hob_cooker_%28Rankin_Kennedy,_Electrical_Installations,_Vol_II,_1909%29.jpg
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They might be but how many have you seen prior to 1980? That's how old the pans are.
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So give me a example of how you use all these at the same time in domestic use.
Do you allow diversity for the time taken for you to put on your skirt and make up on
http://eil.com/Gallery/469098b.jpg
before you plug all these appliance in?
Diversity applies to normal people not freaks like you.
--
Adam



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Denise is a woman who can multitask
--
geoff

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On Sat, 13 Nov 2010 22:10:47 -0000, "ARWadsworth"

Indeed. I have a separate 40A radial circuit to feed a double fan oven and a ceramic hob. The washer/dryer, kettle, microwave (certainly not 2kW!) are all on a normal downstairs ring with a 32A MCB. Even when I'm using both ovens (rarely), and couple of hob rings, (as well as a bit of tumble drying) I've never tripped an MCB, or even the incoming fuse when occasionally boiling the kettle (which is a very rare occurence in my household).
What's a "plug in fish fryer", BTW? I'm a vegetarian.
--
Frank Erskine

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Frank Erskine wrote:

Sunday lunch: Oven with 13A plug doing the roast (eg 2kW). Hob with 13A plug doing pan of spuds, pan of misc veg (eg 2kW). Washing machine doing the Sunday laundry (eg 1kW rising to 2kW).
Already coming up to 6kW and the fridge hasn't even kicked on yet.
JGH
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Well a 32A MCB should never trip with loads upto 8.3kW. So sticking another 100W on for the fridge will not make any difference even if there is already a 6kW load and some inrush current from the motor.
It will also supply 10.6kW for an hour before tripping. The oven and hob spend more time using no electricity than using electricity when in use (they cycle on and off once they have reached cooking temperature). The washing maching is probably using electricity most of the time due to the motor but that is not a big load.
Cheers
--
Adam



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On 14/11/2010 14:29, jgharston wrote:

The important point to keep in mind is that is the maximum power, not the average. It will draw 2kW for a few mins when warming up, but after that will cycle on and off to maintain temperature. The result will be a significantly lower average load.

Hobs tend to be on dedicated circuits...

Again a couple of kW for heating purposes - but probably only for 10 15 min bursts as it does a fill for a hot wash. The motor will be a significantly lower load.

Nowhere close to even 6kW in a form that counts, and a fridge is a fairly small load.
Consider the example of a 15kW cooker given in the OSG. That is a peak load of over 65A. However the recommended circuit to supply is it a 32A radial.
One would assess the actual real world current demand as 10A + 30% of the remainder. So 10 + 55 x 0.3 = 26.5A
Look at the trip response of a 32A MCB:
http://wiki.diyfaq.org.uk/images/d/d4/Curve-MCBTypeB.png
Even if you flip all the knobs round to "full" on the oven and hob, and manage to draw 65A, the MCB is not going to trip on its magnetic response (you need north of 96A for that, and possibly as much as 160A). The thermal part of the trip will tolerate that load for at least couple of minuets. By which time the stats on the rings will already be reducing the demand dramatically.
The point I am trying to make is not that you can't overload a circuit and cause it to trip - obviously you can if you try hard enough, or design it badly enough. However what matters is the sustained average load, and for many domestic appliances this is often significantly less than the peak load. Circuits will also safely supply power at well over their nominal maximum for short durations. So a 32A circuit may supply a constant average load of 30A, but that may represent a peak load of significantly more if you go round adding up the numbers on each appliances spec plate.
--
Cheers,

John.

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On 12/11/2010 08:56, A.Lee wrote:

You surprise me - I've fitted precisely three new (ie single, built-in) ovens in the past 5 years, and all of them did have a 13A plug prefitted.
David
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Why not?
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On 11/11/2010 21:56, snipped-for-privacy@gglz.com wrote:

Hmm. I fitted a roller shutter garage door a few years ago. The destructions specified plug and socket. When I queried this I was told I could of course use a FCU for isolation but most electricians preferred plug and socket.
I have a FCU for boiler isolation but it is by the programmer, not the boiler. Is this now deprecated?
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On Nov 11, 9:41 pm, "John" wrote:

An *unswitched* socket is acceptable. A switched one isn't, as some are only single-pole switched and someone might switch off but not pull out the plug.
A spur box with dp switch is what has been suggested.
Owain
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Let me guess - they will send you a quote to do the work?
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