Opinions on the load of this cooker circuit???

[Joe S]

I have been to look at a job tonight for a new oven to be installed. The circuit is a 6mm T&E with 32a MCB. The appliance end of the circuit has the Electric hob (5.7kw) wired into a Cooker connection point and it also has a spur in 2.5mm for the old oven which has been binned. They have bought a 3.5kw Oven as a replacement but according to the diversity calc the total Load is 35.2A. They are talking of a Gas hob in the future. Would you run another circuit to accomodate the oven or get them to buy a gas hob now???

Thanks alot.

 

[Guest55]

what diversity ?
show us your maths
;-)

 

[rattlehead85]

Well give them the choice! If you have done the calcs and proved the existing circuitry is insufficient you explain this and give them the options. If they refuse new circuitry or decide against fitting the gas option then you turn around and walk away. Let some other mug put his name on the line if they want an incorrect job.

 

[MDJ]

Have to agree haha, diversity you say?

 

[Joe S]

First 10A of the load, 30% of the remainder then add 5A if a CCU with single socket. I have no single socket above w/top.

 

[MDJ]

I have had a hard day, however My calculation is a lot less than that.

 

[Joe S]

My fault, my day was obviously harder than I thought, lol! I make it 31A which is fine. I thought my original sounded wrong which is why I jumped on here. Sorry fellas

 

[telectrix]

dump the 2.5mm. fit a dual CCU on the 6mm from the isolator, cable to each in 6mm or 4mm. sorted. allowing for diversity , your current demand is 20A, or 25A if the isolator has a socket outlet.

 

[Rampantchilli]

i must be wrong then, i worked it out to 19A with out a socket.
5700 + 3500=9200
9200/230= 40
10A+
30%of (40A -10A)=
19A

mind you, my kitchen fitter always said i had a magic calculator

 

[telectrix]

give you that. i did it in me 'ed and used 1/3 of the 30A to make it an easier calculation.

 

[Guest55]

My fault, my day was obviously harder than I thought, lol! I make it 31A which is fine. I thought my original sounded wrong which is why I jumped on here. Sorry fellas

too late !!! the customer has already fitted gas instead lol.

 

[MDJ]

good point about the socket outlet Tel, I actually forgot that, I worked it out at around 19 amps, but it could be 24, either way not 35 haha

 

[telectrix]

if E54 was reading this he'd say a 32A fed 6mm is good for 15kW cooker and has been since he left school 60 years ago.

 

[Joe S]

i must be wrong then, i worked it out to 19A with out a socket.
5700 + 3500=9200
9200/230= 40
10A+
30%of (40A -10A)=
19A

mind you, my kitchen fitter always said i had a magic calculator

Is that how the calc should be done?? My old boss taught me the other way which is how I came up with 31A

 

[telectrix]

that's spot on. but i ( for some reason known only to my psychiatrist ) use 33%, not 30%.