Multiple cooking appliances.

[Soulsurfer]

Hi all,
Just looking into a kitchen refit where the customer has gone a bit excitable with the cooking side of things !

Have done lots of installs with two appliances on the one circuit but anyone know of any issue with feeding three rather than run a new circuit for say the new hob alone ?

I have an existing 32A rcbo on a 6mm twin for built in oven now and hob but new kit is an oven at 3.45kW
Combi oven / micro at 3.6kW

and finally an induction hob at 5.6kW
24.3A fuse rating on spec sheet so they haven't allowed any diversity.
Anyone fitted them with a diversity applied ? as I haven't fitted any induction before.

I'm making it a shade under 27A for the oven and combi together,

and if allowed on induction 18.7A approximately but I'm thinking likely run a new circuit from cu at the full load rating the manufacturer of the hob has given.

 

[Wilko]

Looking at OSG Appendix A and noting coffee not kicked in yet so hopefully I've understood correctly ...
10+13.5+5(say)=28.5A for domestic and
24.3+12.5+9=45.8A for small shop.
Translation : if the customer likely to go nuts with new kit (ask them?) try to sell them on the idea of a new supply

 

[Midwest]

When I've calculated diversity for domestic ovens, I've applied diversity to each appliance individually, not the total load added together.

I'm not sure if that is the right interpretation, but my thinking is the end user can operate each appliance as they choose to, as opposed a singular appliance preventing them from using all heating elements, if you get my drift. Like a single oven, where you can't use the grill & main oven simultaneously.

 

[Richard Burns]

It would probably be OK on the standard arrangement (subject to Wilko's caveats) but if you have the option to run a new supply for the hob then this means you are very safely covered.
The customer will need to be informed that they are using a lot of power and be sensible!
If you turn everything on and then jump in your 10.5kW electric shower you could get the main 60A fuse to go!

 

[Octopus]

2 appliances - OK, adding a 3rd may push it............ I would probably recommend a 2nd supply OR changing the induction hob for one with a 13A plug!

 

[Wilko]

When I've calculated diversity for domestic ovens, I've applied diversity to each appliance individually, not the total load added together.

I'm not sure if that is the right interpretation, but my thinking is the end user can operate each appliance as they choose to, as opposed a singular appliance preventing them from using all heating elements, if you get my drift. Like a single oven, where you can't use the grill & main oven simultaneously.

It would be interesting to compare the two methods, hopefully it would have the same outcome

 

[buzzlightyear]

and if allowed on induction 18.7A approximately but I'm thinking likely run a new circuit from cu at the full load rating the manufacturer of the hob has given.

looking at that loading you have given .I makes more sense.reg 433.1.103 (111)connecting cookers hobs
exceeding 2kw on own dedicated r/circuit.
how many times we have been around the houses with hobs &cookers on this forum!

 

[buzzlightyear]

I forgot soulsurfer in channel islands .by the time the bong drums start banging. he would be able to hear it!

 

[hightower]

I makes more sense.reg 433.1.103 (111)connecting cookers hobs
exceeding 2kw on own dedicated r/circuit.

My understanding is, using a dedicated radial circuit means not connecting it among other appliances such as on the RFC etc. It doesn't mean a radial for each appliance over 2kW.

You can have a dedicated radial for all three appliances, just so long as that circuit meets design requirements. It's still a dedicated circuit for those appliances.

 

[buzzlightyear]

when I do installs cookers hobs ,on the own dedicated circuit. but that's for me only.
with this day and age you will never know .

 

[Phil Thompson]

After being caught out a few times by being given incorrect (smaller) kw ratings of induction hobs, I now just pull in a seperate feed for them than the oven when I hear induction hob mentioned.

Last time was given a similar rating to the OP, however on day of fitting it was actually 7.8Kw.

I see more and more folks on my Facebook feed doing batch cooking at weekends due to work commitments during the week. So they are using all rings and ovens to be doing as much as they are doing, no longer just a Christmas dinner thing anymore for some households to be using full ratings of cooking appliances as it used to be.

 

[Midwest]

It would be interesting to compare the two methods, hopefully it would have the same outcome

Don't think your following what I'm suggesting Wiko.

For the three appliances of 3450w, 3600w & 5600w, using Table A1 (applying diversity separately) I get a figure of 37.5amps (no sockets).

Or have I got my maths wrong?

 

[telectrix]

all 3 in use are never going to pull >45A, so a single 45A isolator, fed 6mm on a 40A breaker if method C. 10mm cable id insulation correction required.

 

[Soulsurfer]

I forgot soulsurfer in channel islands .by the time the bong drums start banging. he would be able to hear it!

What's the bong drums dare I ask !

 

[buzzlightyear]

What's the bong drums dare I ask !

their you go soul train!

 

[Midwest]

when I do installs cookers hobs ,on the own dedicated circuit. but that's for me only.
with this day and age you will never know .

buzz are you sparksburntout's twin or doppelganger or even his alter ego, as he never seems to bring you to task about your atrocious spelling and grammar

 

[Soulsurfer]

Ha ha loads of them today ! Battle of Flowers on. Bongo bongo time lol, only the other Bong thing you'll find down where I surf but that's nothing to do with electrics

 

[Soulsurfer]

Ha ha loads of them today ! Battle of Flowers on. Bongo bongo time lol, only the other Bong thing you'll find down where I surf but that's nothing to do with electrics

 

[buzzlightyear]

buzz are you sparksburntout's twin or doppelganger or even his alter ego, as he never seems to bring you to task about your atrocious spelling and grammar

sorry sir !

 

[Wilko]

Don't think your following what I'm suggesting Wiko.
For the three appliances of 3450w, 3600w & 5600w, using Table A1 (applying diversity separately) I get a figure of 37.5amps (no sockets).
Or have I got my maths wrong?

You're right, but I've got it now. Your maths are correct, or I make the same mistake
The answer is quite different using Table A1 method, as its got 3 lots of 10A, vs only one lot when using Table A2. I think A2 is the one to use for this, just going by its name (?).