I have a single large electric cooktop- it uses a 60amp circuit. I was looking to replace it with a 30" 40 amp cooktop and a 15" 20 amp cooktop- can I wire these two together (they would both connect to the wiring beneath the cooktop, then travel along a single 60 amp wire to a single 60 amp breaker)?? Is that ok?

 

No. You are proposing to overprotect both appliances. In theory, you could have a serious fault in either appliance and never trip the 60 amp breaker. That being said, I have seen it done before, but it isn't a good idea.

 

Curious....why two cooktops? Is this a commercial application?

 

I'm curious too, but I doubt it's commercial.. My thoughts are more along the lines of entertaining/dinner party needs.

 

Ah so the wire should be able to support the load I assume, but their isn't proper device protection. Could I run the 60amp wiring to some sort of junction box under the cooktop which is fuse protected with a 20 and 40 amp fuse and then run the 2 cooktops off of that-essentially creating 2 seperate circuits? By fuse I mean circuit breaker I think.

I have a large 46" electric resistance cooktop. I hate electric resistance cooktops- I cook alot and it takes forever to boil water. This is set in granite. Running gas (or electric) would be very very difficult since it has a second story above it, among other complications. So I was eyeing an induction cooktop. Well unfortunately no one makes 46" wide induction cooktops- so I was looking at getting a wolf 30" wide induction cooktop with another 15" wolf cooktop (maybe electric resistance) and put them together- they are designed to be modular like that- but looks like per wolf's instructions they do require their own seperate circuit- just now seeing that. I would love to just get a 36" wide induciton cooktop, but the hole in the granite would be 10" too wide- the granite can't really be patched since it's natural/unique.

 

The only legal way to do it using the existing feeder would be to install a 60A subpanel with 40A and 20A breakers. However, said subpanel can NOT be installed in a cabinet under the counter. It needs to be on open wall with 36" clear space floor-to-ceiling in front of it.

Is this on an exterior wall by chance? And what is below? Finished basement or slab?

 

the kitchen is in the middle of the house- second story above it, slab beneath it. There is no exterior wall adjacent to it- I've had a plumber look at running gas and told me 'I suppose I could do it' followed by a nasty explanation of how difficult it would be...

 

Yeah he's right, in that situation there's just no pretty solution. Well that blows what I was going to suggest out of the sky.. Wish I could tell you something better..

 

Pros how is this idea. Put a false back in a cabinet only one or two inches back from the door at the front of the cabinet and then flush mount the subpanel there. Assuming your 30">x36"^ when the door is open would that satisfy code?

 

Ray, I don't see why that wouldn't satisfy the code requirement. Since the OP is asking about cook tops and saying I'm imagining having it on the upper shelf of the lower cabinet. Provided, of course, that the splice to extend the existing circuit can be kept accessible and the extended wiring and subpanel can be made, and kept, secure.

 

so I'm confused- I was trying to read more (and drinking a beer) and seems like at least some people were saying NEC allowed for a cooktop and an oven to be on the same circuit? Just curious how 1 oven and 1 cooktop on the same circuit are ok, but 2 cooktops aren't?

Here is an example:
Can You Install a Cooktop and Wall Oven on the Same Circuit? - One Project Closer

 

I think what Casualjoe mentioned her is what is the governing factor. A standard wall oven and a four burner cooktop have a similar wattage requirement and could thus be protected by a single breaker of the size required for the oven. In your case however, the very large wattage differences between the two cooktops would make a suitable size breaker impossible. If you put a breaker large enough to protect the 40A cooktop, your 20A cooktop loses it's protection. If you protect the 20A cooktop with a 20 A breaker, you will protect both units, but will always be popping the breaker from overload. The sub panel is the correct choice here with a 20A & 40A breaker.