Abstract: A switching unit for connecting a load to a mains as a function of a demand for a consumption current by the load comprises a mains port for electrically connecting the switching unit to the mains, a load port for electrically connecting the switching unit to the load, a switching element for producing a substantially conductive electrical connection between the mains port and the load port in its closed state and substantially breaking the said electrical connection in its open state. Furthermore, the switching unit comprises current measuring means for measuring a consumption current consumed by the load, and the control means, which are connected to the switching element, are designed to bring the switching element into the open and closed states on the basis of a consumption current measured by means of the current measuring means in an at least temporarily closed state of the switching element.

Abstract: A method for determining the degree of hardening of a hardenable material determines the complex electrical permittivity. The .di-elect cons."(t=0)/.di-elect cons."(t) ratio, where .di-elect cons."(t) is the imaginary part of the complex electrical permittivity .di-elect cons.'(t)-j.di-elect cons."(t), is determined as a measure of the strength of the material at an instant in time t. The .di-elect cons.'max/.di-elect cons.'(t) ratio of the real part of the complex permittivity can also be determined as a measure of the strength. These ratios are similar in shape to the curve of the strengths of the hardenable material with time.