This paper discusses an automated method to build scan chains at the register-transfer level (RTL) for powerconstrained at-speed testing. By analyzing a circuit at the RTL, where design complexity is lower than at the gate netlist level, one can divide a circuit into multiple partitions, which can be tested independently in order to reduce test power. Despite activating one partition at a time, we show how through conscious construction of scan chains, high transition fault coverage can be achieved, while reducing test time of the circuit when employing third party test generation tools. Furthermore, as shown in experimental results, by constructing scan chains for the partitioned circuit at the RTL, area and performance penalty of the design-for-test hardware may be reduced.