Here is a bit of tutorial.

First, do not pay as much attention to total power requirement. Instead, look at the power of the largest most powerful hob. I suggest finding something that is around 3,500 watts or better. Unfortunately, I find the stats at the induction site incorrect in some cases so you may have to contact the manufacturer to get the correct data.

The total power requirement has to do with all the hobs running together. But there is a bit of complexity in that some (most) of the units cannot handle the full power. So they allow combination of hobs being on until the max is reached at which point, you lose power as you turn things on.

Fortunately, I supsect few of us will ever attempt to use all the hobs at once so the max power consumption of the unit is of little consequence in my opinion.

Now a bit of math :): Watts = voltage x current.

The watts you already know like the 3,500 watts above (same as 3.5 Kw with "k" meaning kilo or 1000). Voltage is 240. So a 3,500 watt hob uses 3500/24 = 14.5 amps (unit of current). Induction units are about 90% efficient so you have to multiple this number by 1.1 to get its full power consumption, arriving at 16 amps.

Put another way, that single 3,500 watt hob uses 16 amps. If your unit is rates at 40 amps, you can have 2 units of that power and one of lower power. Or some other combination like that.

The noted comment I think talks about the fact that a 40 amp circuit may exist in a home from another electric cooktop that might have already been there. But to the extent you are rewiring your kitchen, it is not consequential that one unit uses 40 amps vs 50 amps (in grand scheme of things).

Hope this makes things more clear. If not, go ahead and ask.

I agree with amirm, except I'm not sure I'd worry too much about maximum power unless you're doing wok cooking.

We have 2500W units and that's about the equivalent of a 22000 BTU gas burner depending on the size of the pan (gas units are more efficient on larger diameter pans). We only use the top power for boiling water and preheating a pan. With 2500W, to boil water for tea takes about the same time as getting out the mugs and tea bags. We never walk away from a pan with oil heating on high power, getting to smoke temp is less than a minute with Sitram pans, Allclad is somewhat faster.

I'd suggest looking more at how low it will go and how many steps there are between the lowest setting and about 2/3 power. At least the way we cook, that's much more important.

On our Cooktek units we don't need to use a double boiler, even for melting chocolate. Generally when frying an egg, once the pan is hot I cook at about 8 - 10 out of 20. Sauteing carrots or asparagus I use about 12 and am very careful. Having near instantaneous response and fine steps makes it easier to control.

Actually I think a real cook would be less concerned about this because because they know better how food responds. When you see commercial kitchens, they're pretty much blasting away at high flame all the time.

arnim is correct in essence. However, I don't believe that you need the 1.1 multiplier.

A 3500 Watt unit uses 3500/240 or 14.58 Amps of power.

The '90% efficient' means that 90% of the heat produced by the 14.48 Amps of power is utilized in heating the food. Gas by comparison is 30-35% efficient, meaning more of the heat produced by the gas is used to heat the air in the room, not the food.

One reason for the difference between the 40 and 50 Amp units is probably a marketing decision. By limiting the unit to 40 Amps of power (a software change only, in all likely hood) they have created a market for themselves that DIva cannot sell to. They can now sell Fagor units into older houses where 40 Amp wiring exists, or houses where just the cooktop is being replaced, or houses where the remodeling budget does not permit a long run of new wire.

Actually pretty smart, when you think of it that way.

A 50 amp cooktop would likely have to do less sharing of power when multiple burners are in use, as it has more available amperage. Fagor/Brandt makes a lot of burnersfor their own stable of companies and for others. It is quite possible thatDiva De Provence has had input in the power and power sharing abilities of the induction burners as they have been in the induction business for quite a while and might have slightly different specs for Fagor/Brandt.

Greg

On 1.1 factor, it is true that we don't really know if they are rating the power consumption or generation. The former would not need the multiplier but the latter would. Cooktek rates their 3,500 watt unit at 16 amps. The only way I can make the math work is to account for efficiency.

Anyway, 10% is not much to worry about one way or the other.

As to not needing more than 2,500 watts, keep in mind that you are talking to a male :). "Mo power" is better :D. Seriously, we want to have something bette than the 22K gas burner which we also plan to get and hence, 3,500. But I have read elsewhere that higher settings may not be needed most of the time.