double oven

[Runner251]

Hi Guys,
Please can any sparks give me advice, I`am going to replace my gas oven with a electric double oven but the cooker switch is in the oven housing, so I will need to take it outside of the housing. The cooker circuit has never been used so switch gear, fuse and cable have never carried any current. The house is 1974/75 with the old imperial cable which I have measure at 4mm dia can you see any problems. also will it be ok to connect up the oven with 6mm from the load side of cooker switch.

many thanks hope some one can help CHEERS

 

[ericmark]

I wonder where you are measuring if it's the copper cores then 12.5mm sq if the copper plus insulation then looking at cable today 10mm sq and since old insulation was a little thicker then around the 6mm sq but if outer sheave then 1mm sq so since unlikely to be 12.5mm sq we really have no idea of what cable you have.

If so old there may be problems with the cable it would need testing to ensure it's OK.

Very likely it is all OK but that is not something which can be done on a forum it needs testing and the equipment costs so much the only real way is to get an electrician to test.

 

[Taylortwocities]

I need two vital bit of information.
Your new cooker. What is the maximum current or power rating as quoted by the manufacturer.?
Also
This cooker circuit. What value is the fuse or MCB on this circuit?

 

[Stoday]

In the 1970's cooker circuits were normally wired with 7/036 cable.

7/036 = 4.6mm²
7/044 = 6.9mm²

 

[Runner251]

Hi Guys,

Sorry in delay in getting intouch wih you all again but been away on some R/R.
First I would thank you all for taking a interest in my question. In reply to your question,

I measured the dia of the the copper core which consists ot 7 strands, which measured 4.2 mm but I presume that this could vary on how tight the core was wound.

On the porcelain fuse holder it`s embossed with 30 amps also the fuse wire is 30 amp.

As to the current used by the oven I cannot help as it`s to be delivered this week,the only thing I tell you it use`s .79KWH.

Hope this will help.

Cheers Guys.

 

[Taylortwocities]

As to the current used by the oven I cannot help as it`s to be delivered this week,the only thing I tell you it use`s .79KWH.


Cheers Guys.

KWh is not what we are after. That is a figure of power consumption over time (and see below for more about that!).

The figure we need is the instantaneous maximum current or power. This will be several kilowatts. [/rant]I do not understand why oven manufacturers do not publish this stuff on their web spec information. Its needed to design a circuit and that has to be done usually a long time before the appliance has been delivered.

[/rant]

Now, that 0.79KWh figure appears on a number of makers sites. Why is this?

Its all about EC directives and energy ratings (surprise surprise).

I believe this is the EN 50304, also incorporated in BS standards.


after a bit of Googling I found reference to an article published in the Journal of Mechanical Engineering. Already in the introduction the four authors, from Slovenia, describe the measurement method.
A special test brick is heated in the oven from 5 to 55 degrees C. The total electrical energy consumption should be below 800 Wh to fulfill Class A criteria. Which helps to explain this razor-sharp 0,79Kwh which is now quoted by many manufacturers.

The World has gone mad. Where's my Merlot, give it to me NOW!!!

 

[EFLImpudence]

The World has gone mad.

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[Stoday]

5° to 55°C?

Is that supposed to be the typical operating temperature range in the oven?

Whatever. The 0.79kWh rating is per use.