Installing a new electric cooktop details
I believe the simplest way to put it is, it needs to be on a dedicated 40 amp double pole breaker.

With a 240 volt appliances there are 2 "hot" lines, usually a red insulated wire and black insulated wire. A neutral, usually a white insulated wire, and a ground wire can be bare wire or sometimes insulated in a green covering.

The 4 wire connection is the accepted code compliant connection, the 3 wire has been phased out, but still does exist in older connections.

I hope this gets the idea across. There are a few well versed electrical guys on SE that really know the ropes well when it comes to electrical issues. They may be able to fill you in a little more.