we have an electric double hob with one small 1kw and one larger 1.5kw hob. On 16A sites we can use both at the same time but on sites with lower can only use one at a time (not sure on using the 1.5kw hob on 6A sites either as tend to go for 10A and above), this isn't too big a problem as they retain heat so can simmer with no power for a while.