Cannon double oven blows fuse

[bigGman]

I have a cannon double oven cooker, it has fan oven, standard oven and separate grill, gas top. I was using both ovens and when I turned on the grill it blew the fuse.
The cooker has 32 amp cable from the back going into a 13 amp fused spur that then goes to a cooker switch.
From past posts I feel it is never safe to assume anything but I will any way......
Can I assume that it shouldnt run into a 13 amp fused spur but should wire directly into a junction box that goes directly into the Cooke switch?

 

[PrenticeBoyofDerry]

The information needed is what does it say in the manufacturers instruction which came with the appliance?
Do you have these?
If not do you know what the output power of the appliance is or the make and model of it?
Was it the MCB/Fuse that tripped or was it an RCD?
32A cable no such thing!

 

[bigGman]

Is 6 mm cable not 32 amp?

 

[bigGman]

The cable from the cooker goes to a 13 amp fused spare, it was the fuse in the spare that blew, no manufactures book, had it for 6 years.......

 

[PrenticeBoyofDerry]

Is 6 mm cable not 32 amp?

No!
6.00mm is a CSA (cross sectional area) of the cable, the cable will have a maximum current it can safely carry depending on the method it is installed and any de-rating factors of that method and voltage drop.
6.00mm T&E can carry a maximum of 47A given the right conditions, such as clipped direct with no de-rating factors.
When designing a circuit, the current required for the load is calculated, this will then lead to a suitable sized protective device to be selected for the load.
Once that is done the cable can then be chosen talking route, distance and method of installation in to consideration. Which can lead to in certain circumstances a 32A MCB protecting a 10mm cable.
So you can not define a cable at a certain amp rating.
Calculation must be made and not assumed.

 

[PrenticeBoyofDerry]

The cable from the cooker goes to a 13 amp fused spare, it was the fuse in the spare that blew, no manufactures book, had it for 6 years.......

I guess this has been sound for six years then?
Just replace the 13A fuse, see what happens!
It could be possible that a supply for a higher rated appliance was installed originally and that your appliance only needs a 13A supply but without having MIs or output values would be guessing!

 

[bigGman]

2nd time which is leading me to think something is amiss.....
So I need to find output of cooker, check mcb rating and measure distance from consumer unit to cooker....

 

[bigGman]

What are de-rating circumstances?

 

[PrenticeBoyofDerry]

2nd time which is leading me to think something is amiss.....
So I need to find output of cooker, check mcb rating and measure distance from consumer unit to cooker....

You need to calculate the output of appliance divide that by supply voltage, that will give you the design current, then select a device that is either equal to or slightly higher.
Then make calculations regarding method of installation and distance for voltage drop, then chose a cable size that is compliant with these calculations.

What are de-rating circumstances?

Thermal Insulation
Ambient Temperature
Cable Grouping

Fuse Type
Voltage Drop
Also when run in conduit/trunking.
Useful link
http://www.tlc-direct.co.uk/Technical/Charts/VoltageDrop.html

 

[bigGman]

Cheers will get back to you.
Why would there ba a fused spare to attach the cooker to? Any ideas?

 

[PrenticeBoyofDerry]

Cheers will get back to you.
Why would there ba a fused spare to attach the cooker to? Any ideas?

It can be done that way using a 13A fused spur (FCU) much the same as using a socket outlet with a 13A plug, other than the plug can be removed but the 13A FCU is hardwired.
It could quite possibly be that is what the MIs stated and was followed accordingly or maybe not?
As mentioned previously if the MIs are not available, the next best thing is design calculations, we can also put in to our design calculation diversity.
Which will take in to account that not all the function of the cooking appliance will be used at the same time, this gives us a little tolerance in the size of device and cable required.
In a domestic installation a 15kW oven/cooker can be protected by a 32A device, meaning the cable used could be 4.00mm T&E as this can carry a maximum of 37A, this is providing erection methods used and route of cable allow.

 

[ban-all-sheds]

What are de-rating circumstances?

Have a read of 4.3.1 - 4.3.11.