Oven and hob again

[tank]

hello all, i would be grateful for some advice or pointing in the right direction from someone more knowledgeable and experienced than my not long out of college self.

on a new build, before i had knew what the kitchen appliance specs were, i installed a 10mm cable from board, through cooker switch, to outlet plate and also a single socket off kitchen ring in adjacent cupboard for oven.

the appliances,

siemens 4 ring induction hob - the instructions give the power draw of the rings when on boost, these add up to 7200w. the rating plate on the hob however states I=20a so i'm assuming the hob has an internal limiter. it has an integral 2.5mm flex.

siemens oven -HB13AB550B the instructions say I=16a and this appliance must not be connected with 13a plug, the rating plate on the oven says electrical connection rating 2900w. ( could this be siemens attempt at diversity? ). it has an integral 1.5mm flex.

i want to put both flexes into the outlet plate and protect with an 40amp breaker ( possibly a 32a but they're are moving in just before christmas dinner so maybe not) but the 1.5mm oven flex is making me nervous. i know the flexes are ok for overload protection but i'm not sure how to prove they would be ok under other fault conditions ie short circuit and earth fault.

any thoughts or advice would be appreciated

 

[Engineer54]

Put both the appliances on a dual Cooker Connection Unit supplied by the 45A cooker switch, and go away sleeping comfortably of a night. You can use either a 40A or 32A breaker, you didn't even need to install a 10mm cable to the cooker switch either, a 32A breaker will comfortably look after any cooking load up to 15KW on a 6mm cable....

Shame you didn't read the multitude of Threads here on exactly the same subject, might even have saved yourself a few bob on materials into the bargain....

 

[telectrix]

eggsackly what he said ^^^^^^.

 

[tank]

engineer54, thank you for your response. i have used dual connection units before but only when i could fit a cable to the appliances myself. these appliances have integral flexes that i cannot change. 2.5mm and 1.5mm. if i connected both flexes to the outlet plate and protected by a 40amp breaker, would this be ok? how could i prove that the 1.5mm flex in particular would be ok under fault conditions when protected by such such a large mcb?

 

[telectrix]

fixed load so overload protection not required.

 

[Octopus]

What you need is a dual outlet plate - Google is your friend

 

[Guest77]

What you need is access to the DIY forum.

 

[telectrix]

or fit 2 single sockets on a dual back box. plug each appliance in.

 

[tank]

fixed load so overload protection not required.

i know, that's not what i was getting at. i wanted to know what consideration if any should be given to the 1.5mm flexes ability to withstand short circuit current when on a 40amp breaker.

 

[telectrix]

adiabatic equation tells me that the minimum size would be 0.55 sq.mm. using a fault current of 200A disconnecting in 0.1 sec.

 

[Simonslimline]

i know, that's not what i was getting at. i wanted to know what consideration if any should be given to the 1.5mm flexes ability to withstand short circuit current when on a 40amp breaker.

Surely you were taught about thermal constraint and shown the Adiabatic equation in College?

 

[Guest77]

Surely you were taught about thermal constraint and shown the Adiabatic equation in College?

Hmm LOL, if he went to college.

 

[tank]

adiabatic equation tells me that the minimum size would be 0.55 sq.mm. using a fault current of 200A disconnecting in 0.1 sec.

thankyou telectrix for the point in the right direction. i think i need to hit the books and have a bit of a recap.

 

[tank]

Hmm LOL, if he went to college.

PROUD TO BE A MENTOR IN THE TRAINEE SECTION.

there are some mentors a trainee can do without. you know what happens when you ridicule someone for asking a question? they stop asking questions.

not me though. i'm too old to give a ****.

 

[sparksburnout]

What you need is access to the DIY forum.

useful as ever