Max demand for double oven and hob

[Ray Pooley]

Just some clarification please.

Max demand for cooking devices.

OSG says 10A + 30% of "connected cooking appliances in excess of 10A + 5A" if a socket is available in the isolator. The oven and hob are two devices. Does the 15A apply to both of them or just the first one?

eg: Oven 4.8 kW Hob 5.5 kW. With a socket available.

15A + (((0.3 x 4.8) + (0.3 x 5.5))/230) = 28.4A

or

15A + ((0.3 x 4.8)/230) + 15A + ((0.3 x 5.5)/230) = 43.43A

Thanks in advance

 

[Ray Pooley]

I only recently got to grips with BODMAS...that's why my biomass boiler is 18x bigger than I needed.
Induction hobs...there is no finer way to cook...IMHO. Especially if you have no gas supply.

Perhaps. But I just checked. They're twice the price and I'm not sure my man pan is compatible. They reckon they are but I'll keep it old school. Might get a second hand one even. See how it goes.

 

[Pretty Mouth]

As for diversity, I would treat them separately. It doesn't make sense to me to treat them as one item as they are not. If one item is on full there is no limiting device to make sure the other is not.

It does make sense to treat 2 (or more) cooking appliances as one when applying diversity. After all, diversity relies on there being several 'elements', with not all of them being on full simultaneously. The more parts there are, the more valid diversity becomes.

You make a very good point about the internal power management of some cooking appliances though. In these instances, I believe it is correct to use the 'sum of the parts' and apply diversity to that, rather than applying it to the appliance rating.

For example, supposing the OP's hob was a 4 zone induction hob, each zone rated at 3.2kW, but internal power management limits it to 5.5kW. The sum of all the zones is 4 X 3.2 = 12.8kW, this is the figure we would use to calculate diversity, not 5.5kW.

 

[pc1966]

Brackets are a great way to get around BODMAS. Makes life easier. For me at least.

Better to have redundant brackets in an expression than the wrong answer from not remembering precedence-order perfectly!

 

[Ray Pooley]

It does make sense to treat 2 (or more) cooking appliances as one when applying diversity. After all, diversity relies on there being several 'elements', with not all of them being on full simultaneously. The more parts there are, the more valid diversity becomes.

You make a very good point about the internal power management of some cooking appliances though. In these instances, I believe it is correct to use the 'sum of the parts' and apply diversity to that, rather than applying it to the appliance rating.

For example, supposing the OP's hob was a 4 zone induction hob, each zone rated at 3.2kW, but internal power management limits it to 5.5kW. The sum of all the zones is 4 X 3.2 = 12.8kW, this is the figure we would use to calculate diversity, not 5.5kW.

Just watched the JW video you posted. It's a pretty recent one. He produces great vids. I have watched loads of them. That's the way to go.
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Better to have redundant brackets in an expression than the wrong answer from not remembering precedence-order perfectly!

I'm a retired computer programmer. Thirty years in the biz. Brackets in formulae are essential when writing code.