A hob includes at least one heating zone having several heating elements, a user interface for setting a heating capacity of the heating zone, and a control unit for operating the heating elements and for distributing the heating capacity among the heating elements according to a heating capacity distribution. The network interface device is configurable to reroute one or more of the internal connections onto the external interface to allow testing of the blocks of the device. The rack unit includes a top, a bottom, and an intermediate portion extending therebetween.