Cable Size

[wee jock]

A customer has bought a Rangemaster cooker 14.8kw, Rangemaster state the FLC is 55amps, cable wiring ref method is 100.............what cable breaker size should I use. This is for a domestic property?

 

[telectrix]

start by applying diversity. this should give you around 25A as a ccc for the cable.

 

[Guest123]

You need to factor in diversity here as it's a cooking appliance and will never get anywhere near the manufacturers rating.

 

[wee jock]

Done diversity using the Kws / v, I'm really looking for someone to confirm what I have in my head or if I'm just mad!

 

[telectrix]

6mm cable on a 32A MCB, unless you want to got to 10mm on a 50A. it's your call. client's brass.

 

[Guest123]

Done diversity using the Kws / v, I'm really looking for someone to confirm what I have in my head or if I'm just mad! 

You tell us whats in your head and we'll give our honest views.:book:

 

[wee jock]

In theory the cooker amps would be 14.8kw / 230v this gives 64.5amps, I've seen on another forum it's full load operating current is 55amps measured at the cooker. So if any of you nice guys out there who do a bit of design I'd greatly appreciate it.

 

[wee jock]

Everything I'm looking at is pointing to 16mm using online cable calculators & iPhone apps. Can't see a 6mm cable taking 55amps! Just saying, that's why I'm asking

 

[johnboy6083]

what the lad are trying to say is that in reality the cooker will never take 55A. all of ther heating elements are controlled by thermostats, and because of that, they will be turning on and off as required. The max Kw rating will be calculated from ading the rating of all of the elements and fans together. This will rarely if ever happen.
read the OSG, page 109 onwards

 

[wee jock]

Johnboy, I understand that and I believe that's why the cooker takes 55 amps and not 65 amps as 14.9kw / 230. Calculate diversity on the 65amps gives you 26.5amps. When I put all the above info into cable calcs, FLC 55, design current 26.5amps, install method 100 keeps telling me 16mm!

 

[wee jock]

Missed out that it's an induction hob, the hob itself is 7.8kw!

 

[telectrix]

why 16mm for 26.5A?

 

[wee jock]

Need to ask the computer that.
Been told you can't apply diversity for induction hobs as the manufacturer has already applied this!
By applying diversity to give you 26.5 amp this is the design current?

 

[Guest55]

Johnboy, I understand that and I believe that's why the cooker takes 55 amps and not 65 amps as 14.9kw / 230. Calculate diversity on the 65amps gives you 26.5amps. When I put all the above info into cable calcs, FLC 55, design current 26.5amps, install method 100 keeps telling me 16mm! 

well either your sums or your software calcs are going wrong somewhere.
i calculate the load to be 28amps after diversity and without a socket in the cooker switch.
so , In => Ib thus your mcb will be 32A.

 

[wee jock]

The hob takes 33amps itself diversity applied, the ovens & grill take 16 amps diversity applied. So total current is 49 amps!