New Oven & Hob wiring

[Andr'e]

Hi Folks
Any help please:
Just bought a BOSCH Electric double oven & Electric Hob

The instalation intructions for both are appauling.I have a brand new consumer unit with 32A circuit breaker installed together with an isolation switch near by the hob area & power outlet box.

Not much spec with the two units but the oven gives no current rating but does specify 4.4kW .

The electric Hob just specifies:
Total electrical connected load 6.6 kW
Max. current draw 29A

Both the hob & oven specify lead Type H05 VV-F or higher.

The question please is whats the best way to wire them both into the same outlet & will my 30A circuit breaker be sufficient & what guage cable is the H05 VV-F?

Would it be a good idea to run a dedicated cable from each appliance into the power outlet on the wall?

Many thanks
Andr'e

 

[mst]

Grey area this one!

Should be 2x 6mm cables on there own circuit supplying each 45amp switch then on to the termination.

coming from non qualified person .

 

[Andr'e]

Grey area this one!

Should be 2x 6mm cables on there own circuit supplying each 45amp switch then on to the termination.

coming from non qualified person .

What i need another power outlet installing & running to another circuit beaker in the box both 45A?

Andr'e

 

[mst]

yeap

But i guess 2x 30-32 amp breakers should be ok.

But do read my signature below

 

[Andr'e]

yeap

But i guess 2x 30-32 amp breakers should be ok.

But do read my signature below

O dear i may be best selling them as i've just had the place re-wired & decorated.No chance of running a fresh line to the box without damage

Andr'e

 

[mst]

before we go any further it might be best to hear from one of the regulars who know more about it than me.

But there is alot of loading there to go on 1x 6mm cable.

I can only tell someone the way i think is the right way.

Anyone else have any comments?

 

[Andr'e]

before we go any further it might be best to hear from one of the regulars who know more about it than me.

But there is alot of loading there to go on 1x 6mm cable.

I can only tell someone the way i think is the right way.

Anyone else have any comments?

Thanks mst.just wondered if there was some kind of seperator or something i could fit near the oven housing without going to the extreme of wrecking my wifes nice decor laying new line .The breaker is a 32A sorry not a 30A.

Andr'e

 

[mst]

I know what ya mean mate

 

[ltheb]

This is a bit cart before the horse, but you may be in luck.

The power rating of your hob is 6.6Kw, therefore load is 29amps.
The oven is 4.4Kw, therefore 19amps (formula is power divided by volts, eg 4400 div by 230 = 19.1amps)

Fortunately when calculating design current we apply 'diversity' which in simple terms means not every appliance draws a full load all of the time.

The formula for cooking appliances is the first 10 amps of the load, then 30% of the rest so for the hob:-

10 + (19 x 0.3 = 5.7) = 15.7 amps

For the oven:-

10 + (9 x.03 = 2.7) = 12.7 amps

Total load for the two appliances will be 28.4 amps.

If the cooker switch also has a 13amp socket you must add 5 amps, this would give you a total of 33.4 amps. If 'yes', this is too high and will trip the circuit breaker. You could change this for a 'cooker switch' only.

Incidentally, you say 'new consumer unit with 30amp breaker.' If so it will be a 32 amp breaker.

Please also ensure that the cable is 6.0mm, any smaller would be unsafe.

Hope this helps

 

[ltheb]

Sorry, I should have added that the calculation assumes no other de-rating factors apply to the cable. Typically, cable surrounded by insulation has to be substantially de-rated. Hopefully this is not the case.

Basic rule for any circuit is design current must be less than or equal to nominal fuse/breaker capacity which must in turn be less than or equal to the cable current carrying capacity, eg. -

28amp load - 32 amp breaker - 6mm cable (40amps approx)

 

[miajanjua]

This is a bit cart before the horse, but you may be in luck.

The power rating of your hob is 6.6Kw, therefore load is 29amps.
The oven is 4.4Kw, therefore 19amps (formula is power divided by volts, eg 4400 div by 230 = 19.1amps)

Fortunately when calculating design current we apply 'diversity' which in simple terms means not every appliance draws a full load all of the time.

The formula for cooking appliances is the first 10 amps of the load, then 30% of the rest so for the hob:-

10 + (19 x 0.3 = 5.7) = 15.7 amps

For the oven:-

10 + (9 x.03 = 2.7) = 12.7 amps

Total load for the two appliances will be 28.4 amps.

If the cooker switch also has a 13amp socket you must add 5 amps, this would give you a total of 33.4 amps. If 'yes', this is too high and will trip the circuit breaker. You could change this for a 'cooker switch' only.

Incidentally, you say 'new consumer unit with 30amp breaker.' If so it will be a 32 amp breaker.

Please also ensure that the cable is 6.0mm, any smaller would be unsafe.

Hope this helps

The Hob load Before diversity is :-
6600/230=28.7A

After Diversity:-
10+1/3*18.7=16.3A

The double oven load before diversity is:-
4400/230=19.1A

After diversity:-
10+1/3*9.1=13.0A

Total load is 16.3+13.0=29.3A
So your breaker is rated correctly at 32A.

Idealy you require two circuits from the CU 4mm2 with 32A and 2.5mm2
with 20A breakers, with two local 45A cooker switches and two cooker
outlets.

With the current setup

All you have to ensure is that you connect the hob to the cooker outlet.

Connect the double oven to a 13A plug and plug it in to the nearest socket.

 

[ltheb]

Yep, I'll go with that too except that if there is a 13amp socket on the cooker switch don't use that one for the oven.

 

[securespark]

Incidentally, you say 'new consumer unit with 30amp breaker.' If so it will be a 32 amp breaker.

Nope. It could be a Type 1 or Type 2 30A breaker. How new is "new"?

 

[Pensdown]

You two have lost me. The poster has a 32amp CCU and he wants to connect a hob & oven to it.

The connected load with diversity is within the MCB rating so assuming the cable has been correctly sized why can't he use the CCU to feed both the oven & the hob via a JB on the load side?

 

[Andr'e]

Incidentally, you say 'new consumer unit with 30amp breaker.' If so it will be a 32 amp breaker.

Nope. It could be a Type 1 or Type 2 30A breaker. How new is "new"?

Brand Spanking new consumer unit.It's a 32A breaker sorry Crabtree (61/B32 MCB).

Andr'e